Cyclopedia Of Architecture Carpentry & Building Vol Ix

1

MIliiiililMli

ill

J

Cyclopedia of

Architecture, ('arpentry, and Build in^>: ./

ON

.\R(

General Referente

IIITECTlRi:, rAKI'KNTRY, BI'll.DINO,

S1'E(

IKK ATIDNS, HIILUINC. LAW,

Work

SrpKKINTKMJKX(

STAIR-Ul

E,

(

ONTRACTS,

KSTIMATING, MASONRY, RELNKORCEI) rONfRETE, STRlCTfRAL ESGINEERINC, AR( IIITECTIRAL I)KA\VIN(;, SHEET METAL I

LI) ING,

WiiKK, 1IE\TIN(;, VENTILATLSt;,

ETC

PreparfJ hy a Staff of ARCHITECTS, miLDERS, EXCilNEERS, AND EXPERTS OF THE IIKWIEST l'K<

/

with

iFESSIONAL STANUINO

ox<er 'Ihrte

'Ihouiond hnj^nwingt

TKN VOL IMKS

(

ami:ki(\\

lllt:A(io

ri-.ciiM( I'm:

m.

><)c:i:tv

Copyright.

1907. 1909. 1912

BY

AMERICAN SCHOOL OF CORRESPONDEN'CE

Copyright.

1907. 1909. 1912

BV

AMERICAN TECHNICAL SOCIETY

Entered

at Stationers' Hall.

All Rights Reserved

London

Authors and Collaborators JAMES

PLANT

C.

Superintendent of Computintr DivUion. OfUcp of SupcrviHini; Architx-ct. Treaj-ury, Wushintfton. D. C.

WALTER LOULNG WEBB, Con.sultinfT Civil

Author of

J.

K.

C. E.

EnKintvr

"KailruucJ Construction,"

COOLIDGE,

Jr., A.

'Economics of Railroatl Construction,"

etc.

M.

Architect. Boston

President. Iloston Society of Architects

ActinK Director, Mu.scum of Fine Arts, Boston

HOLST, A.

H. V. vo.N

B., S. B.

Architect, Chicago

President, Chicaso Architectural Club

FRED

HODGSON

T.

Architect and Editor Member, Ontario Association of Architects Author of "Modern Carpentry." "Architectural Drawinar, Square," "Modem Estimator." etc.

GLENN

M.

HOBBS.

5>elf -Taught,"

"The

Ph. D.

Secretary. American School of Corresiondcnce

FRANK

O.

DUFOUR,

C. E.

Assistant Professor of Structural EnKineerinit. University of American Society of Civil Ensineers

SIDNEY

T.

STRICKLAND.

Illinoi*

S. B.

Masnachuiietts Institute of Terhnoloiry tkiAa Am Beaux Arts. Paris

WM.

II.

LAWRENCE.

i'rufraxir

iif

S. B.

Arrhltortural Knidnerrini:. Mawiarhuned* Institute of

Twhnolovy

Steel

Authors and Collaborators— Continued

EDWARD NICHOLS Architect, Boston

^«

H.

W. GARDNER,

S. B.

Associate Professor of Architecture, Massachusetts Institute of TechnoloEy

JESSIE M. SHEPHERD, A.

B.

Associate Editor, Textbook Department, American School of Correspondence

GEORGE

C.

SHAAD,

E. E.

Professor of Electrical Engineering, University of Kansas

MORRIS WILLIAMS Writer and Expert on Carpentry and Building

V»

HERBERT

E.

EVERETT

Professor of the History of Art, University of Pennsylvania

V ERNEST

L.

WALLACE,

B. S.

Assistant Examiner, United States Patent Office. Washington. D. C. Formerly Instructor in Electrical Engineering, American School of Correspondence

V OTIS W. RICHARDSON, LL.

B.

Of the Boston Bar

WM.

G.

SNOW,

S.

B.

steam Heating Specialist Author of "Furnace Heating." Joint Author of "Ventilation American Society of Mechanical Engineers

W.

HERBERT GIBSON, Civil

ELIOT

B. S., C. E.

Engineer and Designer of Reinforced Concrete

N.

JONES, LL.

Of the Boston Bar

B.

of Buildings"

Author) and Cullaburuturs— Continued R. T.

MILLER.

A. M., LL. B.

Jr.,

School

I'rt-sident. Aiiu-rican

i>{

Corrmponijenct^

WM. NEU BECKER liMtructor, Sheet Metal

Department of

New York Trade School

WM. BEALL GKAV Sanitary EnKint-er Member, National Asthxriation of Master Plumbers

EDWARD MAURER.

B. C. E.

rroffs.sor of Mechanics, University of Wisconsin

EDWARD

TUCKER,

A.

S. B.

Architectural Enjrineer

Member. American Society of

EDWARD

EnKineers

Civil

WAITE

B.

Head of Instruction Department, American School American Six'iety of Mechanicul EnKineers

of Correspondence

Western Society of EnKineers

ALVAH HORTON

SABIN, M.

S.

New

York Univor«ily Author of "Technoloify of I'liint and Varnish." American Society of Mechanical Engineers Lecturer

GEORGE

R.

in

METCALFE,

American Institute

^Alitor,

etc,

M. E. cif

Electrical Enifim-i-rs

Formerly Hcud. Technical i'ublication Departtiient. WestinKhousa Electric turlHK Co.

HENRY

M.

Editor

CHAS.

L.

"

HYDE Technical World Magazine"

HL'BBARD,

Conniilllnir Knirineer

Kormrrly with

.S.

S.

B..

on lleatinu.

Homer

M. E. Vi'ntllntlnff. I.lithtinii.

Wmaltirlilun Co.

ami I'owrr

& Manufac-

Authors and Collaborators— Continued

FRANK CHOUTEAU BROWN Architect, Boston " Letters and Lettering'

Author of

DAVID

GREGG

A.

Teacher and Lecturer

CHAS.

B.

in

Pen and Ink Rendering, Massachusetts Institute of Technology

BALL

Chief Sanitary Inspector, City of Chicago American Society of Civil Engineers

ERVIN KENISON,

S. B.

Assistant Professor of Mechanical Drawing, Massachusetts Institute of Technology

CHAS.

E.

KNOX,

E. E.

Consulting Electrical Engineer

American Institute of

JOHN

H.

Electrical Engineers

JALLINGS

Mechanical Engineer

FRANK

A.

BOURNE,

S. M.,

A. A.

I.

A.

Architect, Boston Special Librarian,

ALFRED

Department of Fine Arts, Public Library Boston

JOHNSON,

S.

Ph. D.

Formerly Editor "Technical World Magazine"

GILBERT TOWNSEND, With Ross

HARRIS

C.

&

S. B.

McFarlane, Montreal

TROW,

S. B.,

Managing Editor

Editor-in-Chief, Textbook Department.

American School of Correspondence

Authorities Consulted

of

editors have freely consulted the standard technical literature America and Europe in the preparation of these volumes. They

THE

desire to exjjress their indebtedness

jjarticularly

to

the

eminent authorities whose well-known works should be everyone connected with buildinjr.

in

the library of

f(j|lowing

Grateful acknowledgment is here made also for the invaluable cooperation of the foremost architects, engineers, and builders in making these volumes thoroughly re|)resentative of the very best and latest practice the design and construction of buildings; also for the valuable

m

drawings and data, suggestions, criticisms, and other courtesies.

J.

JOHNSON,

B.

C. E.

Formerly Dean, CoIIckc of Mechanics and Enfrineerinir. University of Wisconsin Author of "Enirinoorintr Contracts and Siiecifications," "Materials of Construction," Joint Author of "Theory and Practice ;in the Desitrnini? of Modern Framed Structures"

V»

JOHN CASSAN WAIT,

M, C,

E.,

LL. B.

Counselor-at-Law iind ConsultinR Entrinecr: Formerly Assistant Professor of Enicineerinjt at Harvanl University Author of "EnKinecrinK and Architectural Jurisprudence"

T.

CLARK

M.

FVIlow of the American Institute of Architects Author of "Buildinir Superintendence." "Architect. Builder, ami

Owner

before the

Law"

FRANK

E,

KIDDER.

Consultinic Architect

C, E.. Ph.

I).

and Structural Knicincer; Kellow of the American Institute of

Architocta

Author of "Architects' and Builders' Pocket- Pook " "Ruildinir Construction and Superintendence: Part I. Masons' Wtirk Part II. CariH-ntem' Work: Part 111. Truued lUxjfs and Koof Trunscs; " "Churches and Chapeln" :

:

V*

AUSTIN

T.

BYRNE,

C. K.

Civil Knsinii'r

Author of "Inspection of MaU'rIals and Workmanship Employed "Ilitfhway Construrtlon"

"y VV.

R.

WARE Form«'rly PriifiM««or of Arrhltrvture, Columbia University Author of "Mieclivo"

In

Conslruclkm."

Authorities Consulted

CLARENCE

A.

— Continued

MARTIN

Professor of Architecture at Cornell University Author of "Details of Building Construction"

FRANK

SNYDER

N.

Architect

Author of "Building Details"

^*

CHARLES

H.

SNOW

Author of "The Principal Species of Wood, Their Characteristic Properties" *>*

OWEN

MAGINNIS

B.

Author

of

"How

to

Frame a House,

or

House and Roof Framing

'

^•

HALBERT

P.

GILLETTE,

C. E.

Author of "Handbook of Cost Data for Contractors and Engineers"

^«

OLIVER COLEMAN Author of "Successful Houses"

^«

CHAS.

E.

GREENE,

A. M., C. E.

Formerly Professor of Civil Engineering, University of Michigan Author of "Structural Mechanics"

LOUIS

de C.

BERG

Author of "Safe Building"

^*

GAETANO LANZA,

S. B., C.

&

M. E.

Professor of Theoretical and Applied Mechanics. Massachusetts Institute of Technology

Author of "Applied Mechanics"

IRA

0.

BAKER

Professor of Civil Engineering, University of Illinois Author of "A Treatise on Masonry Construction"

GEORGE

P.

MERRILL

Author of "Stones for Building and Decoration"

FREDERICK W.TAYLOR, M. E., andSANFORD E.THOMPSON, S. B., C.E. Joint Authors of

"A

Treatise on Concrete, Plain and Reinforced"

Authorities Consulted— Continued

A. W.

BUEL

and C. "

Joint Authoni of

1111. L

S.

Reinforced Concrete"

NEWTON HARRISON, Author of

E. E.

Klectric Wirinir.

DiaKrama anJ Switchboard*"

•V

FRANCIS

B.

CROCKER.

E. M.. Ph. D.

of Department of Electrical Enuinecrinir. Columbia Univemity; American Institute of Klectrical Eni?ineer8 Author of "Electric LiRhtini?"

Head

i

i

.idem.

V J. K.

CKAVATH

LANSINGH

and V. K.

Joint Authors of

"

Practical Illumination"

JOSEPH KENDALL FREITAG. Authom of

WILLIAM

"

BIRKMIRE,

11.

B.

S.. "

Architectural Enitincorink'."

C. E. Fireproofinif of Steel BuildinKs"

C. E.

"

Author of IManninj: and Construction of Hiith Office BuildinRs." "Architeotural Iron and Steel, and Ita Application in the Construction of Buildings." "Compound Riveted Girders," "Skeleton Structures." etc.

EVERETT

CROSBY

U.

Joint Authors of

"

and

HENRY

A.

Handbook of Fire Protection

FISKE for

Improved Risk"

CARNEGIE STEEL COMPANY Author* of "Pocket Companion. ContaininK Useful Information and Tables AppertainInK to the

J. C.

lIiMS

of Steel"

TKAUTWINE,

C. E.

Author of "Civil Kniclncer'a Pockct-Hook"

"y

ALPHA

PlKia'E .lAMLSON, M.

Aiiolitunt PrufesHor Autliiir of

..f

K.

Mi-ctmnliiil Driiwrnn.

"Advnnoi-d Merlmnlcnl Drawinit"

V»

FRANK CHOUTEAU Arrlillrct Aiithiir of

BliOVVN

ikinlnn

" t.<>ttrr
nnM

l.«'lt<'rintt"

Purdue

l'nlver»ltjr

Authorities Consulted

— Continued

HENRY McGOODWIN Author

of "Architectural Shades

and Shadows"

^«

VIGNOLA Author of "The Five Orders of Architecture," American Edition by Prof. Ware

CHAS.

D.

MAGINNIS

Author of "Pen Drawing, An

FRANZ

S.

Illustrated Treatise"

MEYER

Professor in the School of Industrial Art. Karlsruhe " Author of Handbook of Ornament," American Edition

RUSSELL STURGIS "A

Author of

Dictionary of Architecture and Building,"' and

"How

tecture"

A. D. F.

HAMLIN,

A. M.

Professor of Architecture at Columbia University Author of "A Textbook of the History of Architecture

RALPH ADAMS CRAM Architect

Author

C. H.

of

"Church Building'

MOORE Author of

ROLLA

C.

"

Development and Character of Gothic Architecture"

CARPENTER,

C. E.,

M. M. E.

Professor of Experimental Engineering, Cornell University Author of "Heating and Ventilating Buildings"

WILLIAM PAUL GERHARD Author of "A Guide to Sanitary House Inspection"

^» I.

J.

COSGROVE Author of "Principles and Practice of Plumbing"

to

Judge Archi-

DRAWIHa

COriSTRUCTION

snov/iriG.

aHUET i^ETAL mUTi. AND VEMTILATOR. VEriTILATIOM WORK.

'Bz.sndJ

Iron Br>a-C€> <

—

IN

M^

-^

r^

JL Vent.

',Wood'^ -iboir

Jomt befwcen Vent.

Secfton&Jl view s'ho\A/l"n^ ventilaJtion pipes conrjcclfed To drum in aJlic e>s.lso sTea^m coils in drum To crcavte sucTion.

a«.rjd.

Foreword HF^

nii)i(l

.\t':iis.

'^

^f 1^^'

^'"'

'^'"^

~

I'volutiuii

constructive methods in recent

(if

as illustrated in tlif use of steel size

i'l^-'i't-'Ji^wl

and complexity of

has created the necessity

foi'

corrt'lated

Carpentry, and

Tin'

lines.

to

lill

practice along a of

Architecture,

this

acknowledged

Cyclope(lia

designed

is

Huildiiiir

buildinjfs,

an antliority wliiih shall

embody accumulated experience and ai)proved variety of

and concrete,

need.

C,

There

close

for

no

is

interdeiwndence of

as the Contractor

and. in fact,

will enter into tlie

C.

Neither

pro.sent

pains

work

the

is

The

Steel

iilace

Architect,

Concrete con-

oi-

on

work

important

who

intelligent estimato,s, or

right-;

the

and responsibilities.

A

s«»nn'thing of Nhisoiuy, FJeeliie Wiring,

tiue


employed all

in

the erection of a

the craftsmen

l)uild-

whose handiwork

completed structure. noi-

expen-^e have lieen

spared

to

make

the

most eimipreliensive and authoritative on the

Hul)ject of Building and

not

legal

othei' trades

same

ing; and the

hi-^

now know

all

of

who cannot make

understands nothing of carpenter must

out

of

in

Building

subsidiaiy trades.

its

today a> niurh

is

with

coinpares

who knows nothing

example,

struction

(hut

indiiNirv

merel\- to create a

its

allied

industries.

work which

will

The aim has

a|>peal

lo

llie

Immmi.

trained

commend

expert, but one that will

itself also

man by

and the self-taught, practical

to

the

beginner

giving him a working

knowledge of the principles and methods, not only of particular trade, but of

for

home

all

The various

try as well.

own

other branches of the Building Indussections have been prepared especially

by an acknowledged authority on

study, each written

the subject.

his

The arrangement

of matter

student forward by easy stages.

is

such as to carry the

Series of review questions are

inserted in each volume, enabling the reader to test his knowl-

edge and make

it

a

permanent possession.

The

been selected with unusual care to elucidate the C, The work will be found to cover

which

little

illustrations

many important

and Reinforced Concrete Construction

on

;

is

Steel, Concrete,

Building Superintendence

;

and methods of awarding and executing Government con-

ples

tracts;

and Building Law.

€, The Cyclopedia

is

a compilation of

able Instruction Papers of the

method adopted

ence, and the

many

of the most valu-

American School of Correspond-

in its preparation is that

School has developed and employed so successfully for This method tests

is

— that of

which

this

many years.

not an experiment, but has stood the severest of

practical use

— which

has demonstrated

best yet devised for the education of the busy

work would have been

without whose impossible.

it

all

to be the

working man.

In conclusion, grateful acknowledgment

authors and collaborators, this

This

Contracts and Specifications, including the princi-

Estimating;

C

topics on

information has heretofore been available.

especially apparent in such sections as those

have

text.

is

due the

hearty

staff of

co-operation

Tabic of Contents Vttl.rMK IX

..

Electric Wiring

By Charles

.

E.

Knoxf

Pa^e •!!

Knob and Tube Wirinit — Wire* Exposed Wired Run in Conduitu: in MoMinit — Armort-d Cable— Fibroun on In»ulator« — Mi-lal Conduit — Armored Conduit SizeH of Comluctom — FormulajJ Tubing — Two- Win- and Thrco-Win- .SyHti-ma — In.sUillation — Location of Outlets — Chaac* for CalcuUitini; I-oiw. Current, etc. Ix>cation of Cutout Cabinets and Distributint: Centers for Feeders and Mains Testintr -Alternatinir-Currcnt Circuita-Drop in A. C. Line*— Wirinsr an Ofllce

—

— Outlet-Boxes— nuBhintc« — FuRC-Boxcs— Cutout Panels Buildintt —Cartridge Fuse.s— Electric Bell Wiring

Electric LightiN(;

.

.

B>j G. r.

.

.

Fuse-Links

Shaad

Page 95

— Manufacture — Carbon Filament— Selection — Distribution of Light — Voltage and Candlepower — Efficiency — Tungsten Lamp— Osmium Lamp Metallic-Filament Ijimps — Tantalum Lamp — Helion Lamp — Nernst Lamp — Mercur>'-Vapor Lamp — Moore-Tube LightArc Lamps — Arc-Lamp Mechanisms — Flaming-Arc Lamp — Power Distribution Illumination — Residence Lighting — Lighting of Public Halls and Offices — Table of Lighting Data Historical Sketch

—

Incandescent

Skylights, Roofing, Cornice

Lamps

Work By — .

William Neubecker

Page

163

—

Weight of Glass— Reinforcing Strips Skylight Bars — Condensation Gutters Single-Pitch and Double-Pitch Skylights— Hip Monitor Skylight— Ventilation— Roof Mensuration — Corrugate
— Miter Cutting — Development of Blanks for Curved Moldings

Plastering

.

...

By Frank Chouteau Brown

Interior Plaatering— Lathing— Plaster Materials- Slaking

MorUr— Rough Cracks

Plaster Finish

— Patent

Plasters

Plastering

—

Plaster

Plastering

By

Painting

and Working Lime—

— Back

— Drying PlasU'r — Plaster Molding — Exterior

Page 297

.\.

H. Sabiu

I'ajro

;!2'.>

Finish — Linseetl Oil —

Data of Ctmi — Crcoaoting — Priming Coat — Paintii— Oil Mixing and Grinding— Thinners and Dryers— White Ix?ad— White Zinc— Adulternls—Tinting Colors Brushes — Fillers — House Painting — Painting Plastered

—

Walls- Repainting — R.">f Painting — Painting Structural Metal — VarnishDamar - Enamel Paints - Floor Finishing -Glaxing Shellac -

....

Index

• »

For page numlicrs. "«> foot of

Page 363

pau<.

For profesaional standing of authors. front of volume.

«'

li'-l

of Aiilhiirs

ami Collaborator*

at

ELECTRICAL KITCHEN IN EDISON BUILDING, CHICAGO

ELECTRIC WIRING .mi:th()I)s oi

T\\v

i^fiienil lieails,

Firt-

an- ikav

may

In-

aj>pn>\(.*(l l»y tlie

tlassiliwi uiultT four

WiHEs Run' Concealed in Conduits. WiuES Run in Moulding. Concealed Knou a.nd Tube Wikino. Wires Run Exposed on Insulators.

1.

3. 4.

WIRHS Under

\\iriii<; wliicli

I'mk'nvriters,

as follows:

2.

I-JIN

CONCnALED

IN

CONDIITS

this general heail, will Ik- included tiie following:

(6)

Wires run Wires run

(r)

Armoreil cable.

(o)

Wires Run use
of

(litlVn-iit iiiftlKMls

National Hoanl of

wikiNO

almost

in

in rigid conduits. in flexible metal conduits.

Rigid Conduit.

The form of

rigid

metal conduit

now

of plain iron gasj)ij)e the interior surj)rej)are
t-xcliisix i-ly, (•oii>i>i>

face of which has

Ik-cii

ing the irregidarities, and which is then coatee is given a thin coat (»f enamel in some eases,

and,

in

cases,

is

o

t

h c

r

galvan-

ized. Fig. shows one make

1

,

Ot

11/

'

enamele«l (Un-

lined

I

'•

KIkI'I Hiiainrlr.l I'lMiilult. riiHif

Co.,

PUtttmrg,

l\t.

conduit.

.\iiother duit,

'^-^

CourU$y of American Conduit Mfg.

form of

rigid

conduit

which consists of iron

jiijM-

is

that

known

as the armortd con-

with an interior lining of pajHT

impregnate*! with asphaltum or ..imilar compound. 'This latter form to the uidinctl l»ilH* is now rapiillv going out of us*-, owing

of conduit

iK-ingclu-aprr ami la^icr to install, and owing also to imj)nive«l mellxNls of pn)tccting the iron pipe frnm corrosion, and to the intniduclion of additioiuil hniid on tin- lonductors, which |«irtly <-om|H'n.sates ft>r the

11

ELECTRIC WIRING

—

Trie introduction of improved devices such as outlet insulators, for protecting the conductors from the sharp edges of also decreases the necesthe pipe, at outlets, cui-out cabinets, etc. pipe being unlined.

—

sity

of the additional protection afforded by the interior paper lining. from one-half inch to Rigid Conduits are made in gaspipe sizes,

three inches in diameter. relating to rigid,

The

following table gives the various data

enameled (unlined) conduit:

TABLE Rigid,

I

Enameled Conduit— Sizes, Dimensions, Etc.

ELECTHIC WIUIN'G TABLi: III in Une Conduit

Two Wires Sizr.

WiHK. U

&.

8 U.

ELECTRIC WIRING that the sizes of conductors which using these tables, for the reason of conduit depend, of course, upon run be safely installed in any

may

and the number of bends in the run. The tables are based on average conditions where the run does not exceed 90 to 100 in the case of the smaller feet, without more than three or four bends, and where the run does not of size for a wires of sizes conduit; given the length of

exceed 40 to 50

feet,

with not more than one or two bends, in the case

of the larger sizes of wires, for the

same

sizes of conduit.

Unlined conduit can be bent without injury to the conduit, if the conduit is properly made and if proper means are used in making the bends. Care should be exercised to avoid flattening the tube as a result the bend over a sharp curve or angle. In installing iron conduits, the conduits should cross sleepers or beams at right angles, so as to reduce the amount of cutting of the

of

making

beams or sleepers to a minimum. Where a number of conduits originate

at a center of distribution,

they should be run at right angles for a distance of two or three feet from the cut-out box, in order to obtain a symmetrical and workmanlike

arrangement of the conduits, and so as

cabinet in a neat manner.

"\\Tiile it is

to

have them enter the

usual to use red or white lead

at the joints of conduits in order to make them water-tight, this frequently unnecessary in the case of enameled conduit, as there

often sufficient

When cement,

enamel on the thread

iron conduits are

or, in general,

make a

water-tight joint.

ash concrete, in

in

where they are subject

action, they should be coated with tive paint to

to

installed

is

is

in

Keene

to corrosive

any way asphaltum or other similar protec-

prevent such action.

While the cost of

circuit

work run

in

greater than any other method of wiring,

iron conduits

is usually the most permanent where the first cost is not

it

is

is strongly recommended the sole consideration. This method of wiring should always be used in fireproof buildings, and also in the better class of frame build-

and durable, and

It is also to

ings. is

be recommended for exposed work where the work mechanical damage.

liable to disturbance or

Wires Run

shown

in Flexible

Metal Conduit.

This form of conduit,

by the manufacturers as a conduit composed of "concave and convex metal strips wound spirally upon each other in such a manner as to interlock several concave surfaces and in Fig. 2, is described

14

ELKCTHIC

W111IN(]

convex surfaces, lx)th exterior aiui interior, thereby a smooth and cijniparatively frictionless surface inside and securing their

prtvstMit

out.

The Owing

fur thr iim-

fielil

cases where rigid

i.l"

form of conduit

this

to its llexil)ility, coiKhiit df this fy|M'

<;iii

is

rapidly increasing.

Ik- ns«il in

nuniemus

the

conduit

could not possi1) y be e

m

1

Its

ployed. is

to

use

be recom-

Fig.

mendeil al)Ove

Vourtt*!/

2.

Flexible Sl.'clC.udult.

of Sterling Electric

Co., Trot/. X. V-

all the other forms of wiring, except that installe
Ix'cause not so water-tight;

and

it is

ver}' difliciilt,

if

not impossible,

tool)tain as workmanlike a condu't system with tiie flexible as with the For completed or old frame luiildings, liowever, rigid type of conduit.

the use of the flexible conduit

Tal)le duit,

is sujoerior to all other forms of wiring. the inside diameter of various sizes of flexible cx)n-

V gives

and the lengths of

conduit for the

is

inside diameter of this

coils.

that of the rigid conduit; and the table given sizes of conductors which may l)e installiHl in the

maximum

various sizes of conduits,

except that a

tandard

same as

the

little

maybe

usetl also for flexible steel conduits,

more margin should

Ix;

allowe
conduits than for the rigid conduits, as the stiffness of the latter makes it

jK>ssil)le

to pull in slightly larger sized contluctors.

TABLE V Orcenfield I-Icxiblc Steel Conduit

Is.HIL'l.

ELECTRIC WIRING

6

This conduit should, of course, be ductors, in the

same manner as

first

installed without the con-

the rigid conduit.

to the

Owing

of this conduit, however, it is absolutely essential to fasten flexibility it securely at all elbows, bends, or offsets; for, if this is not done, con-

siderable difficulty will be experienced in drawing the con-

ductors in the conduit.

The

rules governing the in-

stallation of this conduit are

the

same as those covering

rigid conduits. Fig.

3.

Use

Elbow Clamp

for Fastening FlexIble Conduit in Place.

of

Double-braided

Conductors are required, and ,, •, iii the conduit should be grounded i

i

i

i

As already stated, the conduit should as required by the Code Rules. be securely fastened (in not less than three places) at all elbows; or else the special

.should

elbow clamp made for

this purpose,

shown

in

Fig. 3,

be used.

In order to cut flexible steel conduit properly, a fine hack saw should be employed. Outlet-boxes are required at as bushing and wires to rigid Fig. 4 shows

coil

of flexible steel conduit

Figs.

conduit.

all outlets,

as well

5, 6, and 7 show, respectively, an outlet box and cover, outlet

plate,

and bushing used

for this

conduit.

are

Armored Cable. many cases where

possible

to

install

There it is

im-

a conduit

system. In such cases, probbably the next best results may

be obtained by the use of steel Fig. 4. A 100-Foot Coll of Flexible Steel Conduit. Courtesy of Sprague Electric Co., New Tork,N.Y. armored cable. The rules governing the installation of annored cable are given in the Natimial Electric Code,

under Section 24-A, and Section 48; also

shown in Fig. 8. Steel armored cable

cable

in

24-S.

This

is

the insulated conductors.

is

made by winding formed steel The steel strips are similar to

strips over

those used

ELECTRIC WIRING for the steel eoiuliiit.

cnishinj; or ahraiilinij

Fig.

strips are fnl

5.

(are tlie

ft.

Box

Outlet

taken

in forming tlie euljle, tu avoid on the eoiuliictors as the steel

for Flexible Slei-1

and formed over the same.

ture, the spools of steel

FIk'.

is

insnlation

In tlie process of mannfaeribbon are of irregnlar length, and when a

outlet IM.itf for Flexible Stt«l Co III u 1 1. I

s|>ool is emj)ty, tin-

machine

is

Flpr

stojipi-d,

;iiid

the ne.xt sj)ooI, the process being eontinutxl.

^ V PlR.

SnrYork, S.Y.

the rililum

There

is

is

no

slarletl

rea.son

on

whv

y*

ft.

Floxlbln

AnnonM

Cable.

Courlny of Spragu* KUttrie

Co.,

Twin PonduotonL Krw York, A". 1*.

In- mndc of any length; but their aetnul made are dctcrmiiuHl by eonvciiien e in haiulling. Ariuoa\]

the conduit cai>lcs could not

lengths as

7.

Courtftynf Spriujut 1

17

ELECTRIC WIRING

8

cable

is

made

in single conductors

from No.

No. 10 B. & S. G.; G.; and three-conducTable VI gives various

1 to

&

twin conductors, from No. 6 to No. 14 B. tor cable, from No. 10 to No. 14 B. & S. G.

in

S.

data relating to armored conductors:

TABLE

VI

Armored Conductors — Types, Dimensions, Size

Etc.

KLKCTHIC WlUIXr, aniioml

tors) art'

HM

(twill

(sinfi;le),

coiuluctors)

HXI.

a
HXL

and

(twin),

damp

:{

('i

armor

lead-encase
for Dniiiian' iiuli>ur work.

caljlf a«la|>tttl is

9

for

marine

conductors)

outside,

Tvjk*

DL

Tvih-s the conductors

wiriiij;.

haw

and an-

e.s[)ecially

adapted

as l)reweries, staljles, and similar places. places, sucli for tlexihUword j)cndants, and is suitable for use«l H is

Tvpe

EM

show windows, and other

similar jjlaees. Tj'pe is reinforcwl, and is suitconl flexihle hut the is the .siime as Type K; use in for marine able for work, damj) places, and in all ca.ses where it factories, mills,

U" subject to ver}' rouf^h handling;;. While this form of wirinj^ has not the advantage of the conduit svstem namely, that the wires can U' withdrawn and new wires will

—

—

any way whatever yet it has many of the advantages of the flexible steel conduit, and it has some additional advantages of its own. For example, in a building mserte
alreadv erected, this cable can be lished between the

where partition walls, conduit or flexible

would

it

steel

walls to an extent that

l)e

tlinirs antl in

the

impossible to install either rigiil

conduit without disturbing the floors or

wouUl be objectionable.

Annore
to outlet,

without Iw'ing spliced and installed on the loop .system. Outlet Utxes should be installwl at all outlets, although, where this is imi)o.s.sible, outlet plates may be used under certain conditions. Clamps should l.r

j)ri.\

iilnl at all outlets,

the cable in place,

and also

switch-boxes, junction-lK).xes, etc.. (o hold to .ser\-e as a means of grounding the steel

sheathing. le.ss expensive than the rigid conduit or the but more expensive than cleat wiring or knob and tube wiring, and is strongly reconunenditl in preference to the

Armored cable

is

flexible steel conduit,

latt.T.

\\II^!:S

Moulding

is ver}'

RIN

IN

MOI IDINCi

extensively used

f<pr

electric circuit

work,

in

buildings which have already U-en wiriNl, and extending also in wiring buildings which were not pmvidetl with ele<-lric cin'uit Work at the time of their erection. 'The n-ason for the |M)pularity «)f circuits in

niouMing

is

that

ruiuvav fur the

it

furnishes a convenient and fairly giKHl-Kniking

wiri's,

und protects ihem fnmi mechanical

II)

injur.'.

ELECTRIC WIRING

10

It in

seems almost unwise to place conductors carrying electric current, wood casing; but this method is still permitted by the National it is

Electric Code, although

not allowed in

where

>

"^

—

%,

sj

T

damp there

places or in places is liability to

damp-

ness, such as on brick walls,

I

in cellars, etc.

The

dangers from the use of

moulding are that if the wood becomes soaked with water, Fig.

9.

Two-Wire Wood MouldiuiJ

there will be a liability to leak-

run in the grooves of the age of current between the conductors

mould-

may not be immediately disthe conductors are Overloaded, and conse-

ing,and to fire being thereby started, which covered.

Furthermore,

if

charred and finally igquently overheated, the wood is likely to become nited. Moreover, the moulding itself is always a temptation as affording a good "round strip" in which to drive nails, hooks, etc. However, the convenience and popularity of moulding cannot be denied; and until

some Rules,

better substitute it

is

will continue to

found, or until

be used

circuits outside of the walls

its

use

is

forbidden by the

to a very great extent for

and on the

running

ceilings of existing buildings.

and 12 show two- and three-wire moulding respectively; and Table VII gives complete data as to sizes of the moulding required Figs. 9, 10, 11,

for various sizes of conductors.

While the Rules recommend the use of hardwood moulding, as a matter of fact probably 90 per cent of the moulding used is of whitewood or other similar cheap, soft wood Georgia pine or oak ordinarily .

S o

— Ac-

-Ab-

-Aa-

Ab-

-Ac-* CD

d GO

Fig.

costs about twice as

work,

be

if

appearance

10.

much is

Two- Wire Wood Moulding.

as the soft wood.

of importance, the

laid out so as to afford

In designing moulding moulding circuits shoulJ

a symmetrical and complete design.

20

For

KI.KCTKK" WIUING

11

is U> In- locatnl in the center of the ceiling, exampli', if an initlct Iw continued from wall to wall, the [Mjrtion l>ey(jn«l the inoiiltlinj,' shouM

the outlet, of course, having

no conductors inside of

tiie

moulding.

If four outlets are to Ih' placetl <jn the <eiling, the r-ctangle of

should

1h'

mi the fourth

coinijlctJ-^l

Kl^,'. 11.

ductors nee«l

Ik-

])lace
increases the cost l»ut

Moulding

is

tubing.

In

many

tors are to run in

portion of the moulding.

I)«ting thi.s

adds greatly to the appeanmce. use
armored cable, instances,

U^ams or studs nmning

.Mi.uMuik

aiul

fre(|nently

of wiring, including

Wood

Thn-i- \Vlr«'

in this

little

moulding no (.tm-

side, altliouj^'h, of coiirM*.

it

is

flexible steel tubing,

po.ssible to fish

in a certain direction;

another direction or

but

and fibrous

tubing U'tween

when

the conduc-

at right angles to the lK>ams or

In such ca.se.s, a junction-lM)x or studs, exj)osed work is nece.s.sary. outlet-box nuist be placed at the point of comiection l)etweeii the moulding and the armored cable or steel tubing.

Where

circuits are

nm

in

moulding, and pass through the

additional protection must be provi(h'
GO

—Ac

Aa— - Ab-*— Aa --^Ab

Ab-

-

floor,

('(xlc liu}«\s,

Agio

«1

m

riK.

12.

Tlir.'c'Wli-r

WimmI

MuuUlliifc'.

As a nilc. it is belter to use C4>nduit for all protect the moulding. of within six feet of the flo«)r, .S4) as to avoid tlumoulding {Mirtions til

|)ossibilitv

of injurv to the «iriuits.

When-

a

combination of in»n

conduit or flexible steel tubing is us«'»l with moulding, it is well t
ELECTRIC WIRING

12

TABLE

Vll

Sizes of Mouldings Required for Various Sizes of Conductors

ol

Z u.

FT-ErrUIC WIRING onlinan' conditions, of the cost of annore
iiietlKxl

other of

wiritii:

tliese

Fig. 13

Ik-

used

l»e

in

tlie Litter

einplovwj, one or tne

preference to moulding,

Device for Maklng"Tap" In

Fig. H.

Fuseless Cord

RDseltf. of Croute- Trinrlt Co., Syraaue, X. 1'.

Where

c-ahle.

or the conthiit .system can

two methods should

13

Mollldlug. 11.

Vourttny of

Courtfity

T. Patttt Ci.,

r/iil>nl
IM.

not only more .suhstantial, but also siifer. Various forms of metal mouldin<j; have been intHMJuced, Init up tt) the present time have not met with the success which they deserve. ns the

work

is

CONCIIALHI) This metlKHJ Cfxlf, althou;;h

of wirini'

many

KNOB ANDTl

is still

HP:

W

IRIN(i

allowed hv the Xaliimal KUctric

vigorous attempts have l)een ma
it

Each of these attempts lias met with the strongest from contractors and central stations, particularly in small opposition towns and villages, the argument for this metluHl InMiig, that it is the chca|)est metluHl of wiring, and that if it were forbidden, many j)laivs nlH)lishe
which are

wire«l

and the use of entirely

ever,

is

according to this

electricity

done away with,

iiielluHl

would therefore

in

would not nuich

Ik.'

such conununities.

winil at

all,

ri'strictetl, if

not

1k>

This argument, lu)W-

onlv a temponirv makeshift obstruction in the

wav

of inevitable

pntgress, and in a fi-w years, mwloubtnlly, the con<-eale«l knob tuU- mcthixl will Ik- forbidden by the Xaiinnnl EUciricCixlc.

The

cost of wiring at-conling to this metluMl

of the cost of circuits

nm

in rigid coniluit,

cost of circuit.s run in armori-tl cable.

88

and

The

is

and

aUuit one-lhinl

alniut one-half of the

latter metluxl of wiring

ELECTRIC WIRING

14

knob and tube wiring, and justly so, wherever rapidly replacing the additional price for the latter method of wiring can be obtained. As the name indicates, this method of wiring employs -porcelain knohs

is

Fig.

and

15.

Knob and Tube Wiring.

work being run concealed between the floor beams The knobs are used when the circuits building. floor beams; and the porcelain tubes are used when

tubes, the circuit

and studs of a frame run parallel to the

the circuits are run at right angles to the floor beams. Fig. 15 shows an example of knob and tube wiring.

In concealed

knob and tube

wiring, the wires must be separated at least ten inches from one another, and at least one inch from the surface wired over, that

is,

tened.

good

knob

from the beams, Fig. 16 shows a

flooring, etc., to

which the insulator

is

fas-

type of porcelain for this class of

wiring.

For knob and

tube wiring, it will be noted that, owing to the fact that the wiring is concealed, the conductors

Fig.

must be kept further apart than on

insulators, where, except in

cleats or

16.

Porcelain Knob.

in the case of

damp

exposed or open wiring may be run on

places, the wires

on insulators only one-half inch from the surface wired ovei.

24

WIRING

EI.F.rruiC Tibrous lubiiiK.

and

tiil)e

Rule 24,

I'iWroiis tuliiug is fre<|ueiitly

and the

wirinj;,

Se<'tion S, of thi"

einj)loy

knobs

an«l

bi'twceii the wires

Xatiunal KUctric Code.

i

tuU-s,

not DVt-r

is

.^.

used with knob

re^julations governiiifj its use are

state*! in this Ituli,u\uy Ik- useil

to

15

where

it is

volts,

in

irn[MJSsilileanle

the difTerenj-e

pmvided ."iOO

pven

This tuhing, as

and

if

in

]x>tential

the wires are not sul>-

Flexible Tubing. "Flexauct" Type.

...

Courttry of Xational iletal Molding Co., IHltgburg, Pa,

ject to moisture.

The

cost of wirinj; in flexible

fil)roiis

tul)ing

is

appn)xiniately about the same as the cost of knob and tul)e wiring. Duplex conductors, or two wires together are not alloweti in fibrous tubing.

Fibrous tubing cable

is

not use
Ritle.i, it

is

outlets refjuire
in

;

must extend back from the

beyond the

outlet.

where conduit or annore
knob and tube wiring) and, as

Fig. 17

shows one make of fibrous

by the one inch

reciuirol

last j)orcelain suj)port to

tubinij.

Table VIII gives the maximum sizes of conductors (doublebraide<J) which may l)e installe
VIII

Sizes of Conductors in I'lbrous Conduit

()

1

ELECTRIC WIRING

16

WIRES RUN EXPOSED ON INSULATORS This method of wiring has the advantages of cheapness, durabiUty,

and

accessibihty.

Cheapness. The relative cost of this method of wiring as comconduit system, is about fifty per cent pared with that of the concealed of the latter if rubber-covered conductors are used, and about forty

per cent of the latter if weatherproof slow-burning conductors are used. As the Rules of the Fire Underwriters allow the use of weatherproof slow-burning conductors in dry places, considerable saving may be effected

by

this

method

Fig.

Is.

of wiring, provided there

is

no objection

to

it

Large l<\eders Run Expose* on Insulators.

from the standpoint of appearance, and also provided that

it is

not

mechanical injury or disarrangement. It Is a well-known fact that rubber insulation has a Durability.

liable to

relatively short

tion does not

life.

Inasmuch as

depend upon

in this method of wiring, the insulathe insulation of the conductors, but on

the insulators themselves, which are of glass or porcelain, this system is much more desirable than any of the other methods. Of course, if the conductors are mechanically injured, or the insulators broken, the insulation of the system is reduced ; but there is no gradual deterioration as there is in the case of other methods of wiring, where

IKHip" SiriH't Substation

li.iini

stri-ft suliHt.til.iii

SUBSTATIONS OF THK CLEVELAND ELECTRIC ILLUMINATING COMPANY. CLEVELAND. OHIO \Vuii<-rii..ii

,l£

.SchllrliliT. Arililli'iln, Clrvplniol.

Ohla.

WIRING

KI.KCTItIC nihlxT

(ItjHMuK'il ujMiii for insulation.

is

olatt's, particiihirly whi're thr

This

tfinperature

17

is

tnie in hot

e.s|K-tially

aUne.

120° V. or

is

For

the wt'atht'rj)r(M)f slow-hum in;; coiuUn-tors on |)orceliun or glass insulators arc esjH*cially reconuntMulc*!.

such

cast's,

'V\w comluctors lu-ing run exjK)se«l, thev niav

Accessibility.

readily repaired or reniove«l, or connections

may lx> made This

inethtjd is

wiring

for

mills, factories,

Fig. 19.

or long conductors.

IS shows

aujples of

T\vo-\Vlre Cleat.

large

ductors, installetl in the

Vork

Gauge

each,

or three

porcelain

conductors,

provided

may

V)e use
the

tlistance

FlK-

Fig. 2a

tors

is

at

con-

fee
New York

cleats

Onc-WJro aoal.

least

21

to

e.\-

e.\jK»sf«l

Life In.surance Huilding, For small conductors, up to say No. B.

City.

and

large

feeder

FJg.

of

esjx'cially

reconunended for

Ije

sime.

to the

New

&

S.

support one, two,

between the conduc-

-I'

r<>ri'<'litiii

hisuUtor fur

Lartcu Couiluctorn.

in
two-wire

.system,

and

2'

inches

a thnv-win* .system where the over '.HM.) volts. The |)otential U'tween the outsi
U'tween the two outside conductors

the cleat

is

fastene«l;

and

in

damp

in

places the win* must

least «)ne inch fr«>m the .surface wireil over.

27

'For

IjirgiT

l>e

helil at

conductors,

ELECTRIC WIRING

18

from No. 6 cleats

to

No.

or knobs.

4/ OB. &

S.

Gauge,

it is

usual to use single porcelain

show a good form of two-wire

Figs. 19 and 20

m

m

m

Fig. 22. Iron Rack and Insulators for Large Conductors. Courtesy of General Electric Co., Schenectady, iV. Y.

and single-wire cleat, respectively. For large feeder or main conductors from No. 4/0 B. & S. Gauge upward, a more substantial form of porcelain insu-

cleat

lator should

be used, such as shown

These

21.

Fig.

insulators are

The

latter

in

form of rack

oo

^ n^t>

in

held in

iron racks or angle-iron frames, of

two forms are shown

-Q^

which

Figs. 22 and 23. is

particularly de-

heavy conductors and where a of conductors are run together.

sirable for

number

In this form of rack, any length of con-

ductor can be removed without disturbing the other conductors. As a rule, the porcelain insulators

should be placed not more than 4h feet apart; and if the wires are liable to be disturbed, the distance between supports should be shortened, particularly for small

conductors.

If

the

beams are

so

far

apart that supports cannot be obtained 42- feet, it is necessaiy to provide a running board as shown in Fig. 24, to which the porcelain cleats and knobs can be fastened. Figs. 25 and 26 show

every

two methods of supporting small conFcr conductors of No. 8 B. & S.

ductors,

28

23. Elevation and Plan of Insulators Held in AngleIron Frames.

Fig.

ELECTRIC WliaXC

19

Juuge, or over, it is not nect'ssjirv to hrt-ak iin»uiul the ln*ain.s, pmviiletl they an* not Hahle to Ik- e«l but the siij)j>ort.s may Ik* plaeed on

(

;

each

iH'aiii.

Wliere the disthe

tance l>et\veen

supp)rts, however, 4\ is greater than is

it

feet,

usually

necessiiry to provide

Ulterniediate |K)rtS,

as

SUJ)-

shown

p 1^,34

insulators Moutnod on Running B
in

Fig. 27, or else to provide a ninning-lMiard.

may

lie

used,

where heains are

25.

Another

which

nietho
than 4\ feet

ajKirt,

is

to

M~

TT^-j-

Fig.

furtlier

Beams.

Method of Supporting Small Conductors. :i

F-^ -ct> Flg.

Intcrmcdlatu SupiK>n for Conductor Ix'twcvu WlJc-Spaccd

27.

Uoam.->.

nin a main along the wall at right angles to the iH'ains, and to have the individual circuits run lietween and parallel t») the U'ams.

FIk-

2<J.

.Mil

li'

"I

of SupiH.!

luK

.1

.s

until

Flu-

In low-<'eiliiig rooms, it is

of

where the conductors are

Usually rei|uirnl that a wtHxIeii

tlic

cdiidiictors, as .shown in Kig.

Where

the conductors

Condiiciort I*rotH nu l.ow (Vllluj:.

2H.

Conductor.

pa.s.s

guard

slri]>

Ik*

liable

plac«'d

f(»

injurA*.

on each side

'2S.

through partitions or walls, they must

20

ELECTRIC WIRING

20

be protected by porcelain tubes,

or,

if

the conductors be of rubber, by

means

of fibrous tubing placed inside of iron conduits. All conductors on the walls for a height of not less than six feet

from the ground, either should be boxed in,or,if they be rubber-covered, should (preferably) be run in iron conduits; and in conductors having single braid only, additional protection should be provided inside of the iron conduit. flexible tubing

bymeans

of

placed

Where conductors cross each other, or where they cross iron pipes, they should be protected by means of porcelain tubes fastened with tape or in some other substantial manner that will prevent the tubes from slipping out of place.

TW0=W1RE AND THREE=WIRE SYSTEMS As both

the two-wire and the three-wire system are extensively it will be well to give some consideration to the

used in electric wiring,

advantages and disadvantages of each system, and

somewhat

to explain

them

in detail.

Relative Advantages.

The

choice of either a two-wire or a three-

wire system depends largely upon the source of supply. If, for example, the source of supply will always probably be a 120-volt, twowire system, there w^ould be no object in installing a three-wire system for the wiring. If, on the other hand, the source of supply is a 120240-volt system, the wiring should, of course, be made three-wire. Furthermore, if at the outset the supply were two-wire, but with a posthree-wire system being provided later, it would be well sibility of a

adapt the electric wiring for the three-wire system, making the neutral conductor twice as large as either of the outside conductors, and combining the two outside conductors to make a single conductor to

until

such time as the three-wire service

is installed.

Of course,

there

would be no saving of copper in this last-mentioned three-wire system, and in fact it would be slightly more expensive than a two-wire system, as will be shortly explained.

The

of the three-wire

is

to reduce the

system — object — copper and consequently the cost of wiring necessary

amount

of

to transmit

a

given amount

of electric power. As a rule, the proposition is usually one of lighting and not of power, for the reason that by means of the

three-wire system

turrent

is

we

are able to increase the potential at which the same time to take advantage of the

transmitted, and at the

30

ELE( TUH: WIHIN'G

j,'rt'atiT

rdiciency of the Idwit

21

If ciirrt'iit

v()haf,'e lain[).

fi»r

|Hj\Vfr

woiihl U* a siinplf muttiT {motors, to wind the motors, etr., for a hij^her voUafje, ami therel»y retluee the vtv.)

of

weight

only werr

crease

it

copjK'r.

however, we

If,

to Ik- tninsinittitl,

the

in-

voltajLje

of lamps, we find that they are not so ellitient, life

nor

their

is

With

so long ^'

t'lK-

iS*-

Thrt-e-Wlrc Syst'-m. wiih N<-iitr;il I'uiiducUir btLWi-i-u the Two outsldo C'ouJuftors.

thestandanl carbon

lamp, life,

has been found that the

it

retpiires

about 10

to

24()-volt

12 ])er cent

lamp, with the siime

more current than the

lamp, has been foimd impracticable, if not iuijxisthem for pressures alxive 120 volts. For this reason

Tunj^sten lamj), sible, to

make

cor-

more

Furthermore, in the case of the resjM)ndin<; 120-volt lamp. eflicient lamps recently intr(Hluce
it

the three-wire system is employed, for by tiiis metluKl we can use 210 volts across the t)utside conductors, and bv the use of a neutral con-

ductor obtain 120 volts between the neutral and the outside con«luctor, enaljUnl to use 12()-volt lamps. Furtherniori', if a that was as economion the market should ever be 210-volt lamp j)lace
and thereby

l)e

svstem would be introduce*!, and 210-volt lamps use«l. As ii . . matter of fact, this

volt

A.

A. I

I

30.

I.Hnips

I

Island.

I

it

is

.si>

Third or N«"Utral Couduftor.

.sjjtisfacton'

as reganis

life,

in

As a nde,

lamp has

120-

Urn

clli«iencv, etc., that

nrarlv alwavs <MUi)loveil.

The whatever

The will

much more

in

Rhode

llOWCNCr, the volt

found

trietl

I'rovidence,

.\rr;iiiK''iI III l':ilr-. Ill SiTl«'-i. I)Ui>.Ml.-.liik' wltli

Necoii.Hliy for

l)een

particularly

O

2 KIg.

has

sevend cities— and

now

two-wire system is

re(|uirnl

is .so

concerning

extremely simple that no explanation if.

three-wire systiMu, howeve.', Iv consideretl.

.31

is

somewhat confusing, ano

ELECTRIC WIRING

22

Details of Three-Wire System. The three-wire system may be considered as a two-wire system with a third or neutral conductor placed between the two outside conductors, as shown in Fig. 29.

This neutral conductor would not be required

if

we

could always have

shown in Fig. 30. In this case, the two lamps would bum in series, and we could transmit the current at double the usual voltage, and thereby supply twice the number of lamps with one-quarter the weight of copper, allowing the same loss the lamps arranged in pairs, as

lamps. The reason for this is, that, having the in series of pairs, we reduce the current to one-half, arranged lamps and, as the pressure at which the current is transmitted is doubled, we can again reduce the copper one-half without increasing the loss in pressure in the

We therefore

in lamps.

see that

we have

a double saving, as the cur-

reduced one-half, which reduces the weight of copper one-half, and we can again reduce the copper one-half by doubling the loss in rent

is

For example, if in one two-wire a case we had straight system transmitting current to 100 of 100 and this system were replaced a volts, lamps at potential by one in which the lamps were placed in series of pairs, as shown in Fig. 30,

volts without increasing the percentage loss.

and the potential increased

200 volts

— 100 lamps

—

being used current carrj'ing really for only 50 lamps, as we would require only the same amount of current for two lamps now that we required for one lamp before. Fur-

we should

to

find, in the latter case, that

still

we were

thermore, as the potential would now be 200 instead of 100 volts, we could allow twice as much loss as in the first case, because the loss would now be figured as a percentage of 200 volts instead of a percentage of 100 volts. From this, it will readily be seen that in the second case mentioned, we would require only one-quarter the weight of

copper that would be required in the first case. It will readily be seen, however, tliat a system such as that outlined in the second scheme having two lamps, would be impracticable for ordinary purposes, for the reason that

lamps

to

be burned

third or neutral it

will

in pairs.

conductor

is

Now,

required

no longer be necessary

to

it is

;

it

would always require the

for this very reason that the

and,

if

this

burn the lamps

conductor be added,

in pairs.

This, then, the object of the three-wire system to enable us to reduce the amount of copper required for transmitting current, without increasing the electric pressure employed for the lamps.

—

is

32

ELECTRIC WIRING

23

With re^anl to the size of the iieiitnil C(iii(luctor, one im[xjrtant must l>e Ixjnie in iniiul; ami that is, that the Rules of the J^ ational

{Mjiiit

Electric

Code

coiKluctor in all interior re(|uire the neutral

nia«le at least as lar;;e as either of the

reasons for this from a

wiring to

staiuljx^int are obvious, bec-jiuse,

fire

Ik?

The

two outside eonduetors.

if

for

unv reason either of the outside eonduetors l)eeame diseonnected, the mi^ht In- re<|uintl to earrv the siime eurrent as the outside eonduetors, ami therefore it should In- of the same eapaeity. ( )f iieutRil wire

course, the chaiiees of such an event haj)j>ening are slight; hut, as the fire haziird is all-important, this rule nuist Ik- complied with for

where there would he a

interior wiring or in all cases

jirohahility of

For outside or umh-rground work, however, where the fire hazjinl would l)e relatively unimportant, the neutral conductor might fire.

lie re»lucetl

in size;

and, as a matter of

fact,

made

it is

smaller than

the outside conductors.

The to use the

so that

it

system.

three-wire system

is

.sometimes

where

installeil

it is

desired

system as a two-wire, 125-volt .system, or to have it arninged mav he use
course, in onler to

)f

do

it is

this,

nece.ssiirv to

make

the

neutral conductor ef[ual to the combined capacity of the outside conductors, the latter being then connected together to form one conductor, the neutral ln-ing the return conductor. This .system is not

reeonnnended except Lsolated plant of

12.')

such instances, for example, as where an is installed, and where there is a |>ossibility

in

volts

of changing over at .some future time

system.

the three-wire,

t«)

In such a ca.se as this, however,

would be

it

12.")-2.")()-volt

where

U-tter.

to design the i.solated plant for a three-wire, 1 2.")-2.")<>-volt po.ssible, system originally, and thru to make the ncutr.il ondiictor the siime <

size as

each of the two

'I'he

oiilsid*'

coMdiictors.

weight of copper re(|uired in a three-wire .system where the is the s;ime size as either of the two outside eon«luct-

neutral conductor ors, is 3 "f

'!'•'•

rei|uini| for a

the s;ime voltage of lamps.*

•V"Tr

eorresjMinding two-win* .system using

obvious that

is

fhf wo-wln> nvHU-m. wi< n'prrwnt

In

If.

It

t

>f

i|ii<

rnrhor

H«

I

I

of ru|i|HT nHjulnnl

J

If

,;

In iw>i k-

i

»

,,

1.1

I

of

f

»in

t

..li.lm lor wen- iimili' 4 of iiiK III iiiiilt'r«rouinl work.

'

'

iIi)<

Haiiiv |M
'

?3

ron-

•

>«

uf Ionh mhI

'

"x. '«»

1

hat n^iiiln^l In the rom»ii>..i,...i,K

wo

»t

.

III

1

1

,-,

oni-li

.o

u 11 mK iwiHwIru nyitli'in IuivImk

p.,

of

lhn'<> loiidiiildi

if

M

lln< wi'lulif

In- iiiiin1iIi< riiiniti'

Ih'

liiiil

this is true, lHM-au.st»,

......

.,

.i.

-..

^

ELECTRIC WIRING

24

as the discussion proved concerning the arrangement shown in Fig. 30, where the lamps were placed in series of pairs, we found that the

weight of copper for the two conductors was one-quarter the weight It is then of course true, that, if we of the regular two-wire system. size as each of the outside conductof the same had another conductor

we

increase theweight of copper one-half, or one-quarter plus one-half of one-quarter that is, three-eighths. ors,

—

In the three-wire system frequently used in isolated plants in which the two outside conductors are joined together and the neutral conductor made equal to their combined capacity, there is no saving of copper, for the reason that the same voltage of transmission is used, and, consequently,

we have

neither reduced the current nor increased

Furthermore, though the weight of copper is the same, potential. is now divided into three conductors, instead of two, and naturally

tlie it it

costs relatively

more

to insulate

and manufacture three conductors

than to insulate and manufacture two conductors having the same As a matter of fact, the three-wire system, total weight of copper.

having the neutral conductor equal to the combined capacity of the two outside ones, the latter being joined together, is about 8 to 10 per cent more expensive than the corresponding straight two-wire system.

In interior wiring, as a for the

mains and

rule,

where the three-wire system

feeders, the two-wire system

is

is

nearly always

used

em-

ployed for the branch circuits. Of course, the two-wire branch circuits are then balanced on each side of the three-wire system, so as to obtain as far as possible at all times an equal balance on the two sides This is done so as to have the neutral conductor carry of the system.

From what has already been said, it is a perfect balance, the lamps are virtually in series of pairs, and the neutral conductor does not carry any current. Where there is an unbalanced condition, the neutral conductor carries

as

little

current as possible.

obvious that in case there

is

the difference between the current on one side and the current on the

For example, if we had five lamps on one other side of the system. side of the system and ten lamps on the other, the neutral conductor would carry the current corresponding

to five lamps. In calculating the three-wire system, the neutral conductor is disregarded, the outer wires being treated as a two-wire circuit, and

the calculation

is

for one-half the total

34

number

of lamps, the per-

KLKCTHIC Wild NT, mi the

c-entage of loss l)eing hasttl

25

across the two outside

[X)teiitial

roiitlia-tors.

The

three-wire system

is

ver}'

generally ernployeil in altenuitiiig-

eurreiit secoiuhiry wiring, as nearly all transformers are built with

three-wire c-oniieetions.

While unhalancing coniluet«jrs, yet

the system

it

will nut alVect the total Idss in

tloes atfeet the loss in the

the outsiile

lamps, for the reason that

usually calculated on the basis of a perfect balance, and

is

divided e<)Ually between the two lamps (the latter Ix'ing consideretl in series of pairs). If, however, there is ur.ljalaiicing to the loss

is

a great degree, the loss in lamps will be increase-*!; and if the entire load is thrown over on one side, the loss in the lamps will lie doubled

on the remaining in

side,

because the

total loss in voltage will

these lamps, whereas, in the case of j)crfect balance,

e(jually divided between

tlie

it

now

(M-cur

would

l>e

two groups of lamps.

CALCULATION OF SIZES OF CONDUCTORS The formula

for calculating the sizes of conductors for direct

currents, where the length, load, and

lows

loss in volts are given, is as fol-

:

The

size of

eondurtor

the curn^rit mullifflicd

(in circular mils) is eciual to

by the distance (.one way), niulliplud hy 21.0, duidid by

tiie

^^^^ rxDx2i.r. in

= D —

which C

V

The

=

eter

^(^

Current, in amperes; Distance or length of the circuit (one way, in feet); Loss in volts between the licginnini^ and end of tiie circuit.

constant (21.0) of this fornnda

of a mil foot of wire of 77''

los^ in vuils; or,

FahR-nheit.

The

and one

foot

named.

Wf

\)S

per

<eiit

resistance

long,

is

is

derivc«l

fn»m the resistjmee

or conductivity a conductor of
t)f

lO.S at the

ti-mperatiire

and eondi)<>

as the length of a tivity by circuit is usually given as the distance one way, and in onler t»» obtain the resistance of lM)th conductors in a two-wire circuit, we must nndtiply this figure (10. S)

'J,

multiply by 2. The formida as alM)ve given, therefore, is for a tw«>wire circuit; and in calculating the si/e of conductors in a thri'e-win* .system, the calcidatioti

plained

shouM be made on

lieri'iiiaflcr.

36

u (wo-wire Im.sis, as ex-

ELECTRIC WIRING

26

Formula

1

can be transformed so as to obtain the loss current which

in a given

may be

carried a given distance with a stated loss, or to obtain the distance when the other factors are given,

circuit, or the

in the following

Formula

manner:

for Calculating

Loss

in Circuit rr

^

Formula

when

_ CX ~

Size, Current,

DX

and Distance are Given

21.6

/^x

CM

y-^)

which may be Carried by a Qiven Circuit of Specified Length, and with a Specified Loss

(or Calculating Current

^^ DX

21.6

of Circuit

when

Formula for Calculating Length

V''; Size, Loss,

and Current to be Carried

are Given

XV ^= CM ex 21.6

X

.X

(4)

Formulae are frequently given for calculating sizes of conductors, etc., where the load, instead of being given in amperes, is stated in lamps or in horse-power. It is usually advisable, however, to reduce the load to amperes, as the efficiency of lamps and motors is a variable quantity, and the current varies correspondingly. It is in

sometimes convenient, however, to make the calculation It will readily be seen that we can obtain a formula

terms of watts.

expressed in watts from Formula I. To do this, it is advisable to express the loss in volts in percentage, instead of actual volts lost. It

must be remembered

above formulse,

that, in the

V

represents the

volts lost in the circuit, or, in other words, the difference in potential

between the beginning and the end of the applied E.

M. F.

The

and

circuit,

loss in percentage, in

any

is

circuit, is

not

the

equal to

the actual loss expressed in volts, divided by the line voltage, multiplied

by 100;

or,

P= From

this equation,

^X

100.

we have:

y^ PE 100

example, the calculation is to be made on a loss of 5 per cent, with an applied voltage of 250, using this last equation, we would have: If, for

— = ,„.

„ 5X250 -— V = Substituting the equation

V= PE ^

36

in

,^ 12.5 volts.

Formula

1

,

we haver

KLECrUIC WUtlNG r

C X Dx

\t

27

21.0

100

C X D X

X

21.6

100

PE C X D X PE This

he reinemherwl,

.should

it

W|iiati()ii

Now,

ajiplieil vollaiijf.

2.100

the

.since

in

pjwer

i.s

= EC),

voltage mtiltipliid by the current (M'

tenn.s of

in

oMprt'.ssttl

watts

the applied follows that is

it

etjual

tt>

E

C

\\\ sul)stiiutint; this value of

xD

C' C'xD

X iMOUv l-MO Uv I

p-= PE

.

,

,

fornuila

tlie

in the e([uation .

,

given above

.

is

)

r

,

(

C

M

•

..

, expresseti \n terms of watts instead ,

I

of current, thus:

^ir which

in

II'

= Power

J)

=

of tlio ciriuit (one

way)

—

conductor; Figure rei)rf.scnting the percentage

P= E*=

Ai)j)lie(l

.-X

2.160

watts transmitted;

in

I.cngtii

_ W'x D X

tliat

is,

the length of one

loss;

voltage.

All the al)ove forniuhe are for calculaticjiis of two-wire cirtiiits.

In

making calculations

for three-wire circuits,

it is

usual to

calculation on the hasis of the two outside conductors;

wire calculations, the alnne formula' can cation, as will

l)e

In-

and

make

the

in three

used with a slight miHliii-

.shown.

In a three-wire circuit,

it

is

usually a.ssuine«l in making the cidon the two sides i)f the

culatinii, that the load is e<|Ually l>alance«l

neutral conductor; and, as the |>otential acnt.ss the outside conductors douhle that of the corresponding poti-ntial acrt>.ss a two-wire circuit,

is it

is

evident that for the siixuv

U-

con
si/.*- <»f

lo.ss in

volts

douMnl

witiiout increasing the jM-rcentage of loss in lamps. I'urtlu'rmore, as the load on one side of the neutral c
coulil

the sy^lcin

is

halaix cd,

is

(iirreiil

rei|iiired

*NoTr..

K

In Knrtntiln 8

l.y

;dl

llie

llinnoiiitM
n'prtwiKM

tlii<

I'

in

virliially

thini side, the curreiu in am|)eres

is

lam|»s. In Ki>riiiuln>

appili')! vnliiiKo,

37

.series

with the load on the

usually one-half the If (' l>e

1

still

sum

of the

taken as the total

lo 4 rf>|imM'iiiii tlu< voliii Uat, liui tli»l

ELECTRIC WIRING

28

current in amperes (that

is,

the

sum

of the current required by all of

we shall have

to divide this current by 2, the lamps) in Formula 1, two outside conductors for a the to use the formula for calculating have to multiply the shall we three-wire system. Furthermore, the to obtain in the voltage lost in the two outlamps by 2, voltage lost the that the reason for side conductors, potential of the outside com the double is ductors required by the lamps themselves.

potential

In other words, Formula

1

will

become

:

21.6 ^^J^CXDX 2 X FX2 - CXDX 21.6 4.' in

which C

= Sum

of current required

D=

the neutral conductor; Length of circuit that

V=

Loss allowed

—

lamps, two outside conductors.

In the same manner,

making

is,

in the

all

by

all

e.,

lamps on both

sides of

of the three conductors;

any one

of i.

(6)

•

of the

one-half the total loss in the

may be adapted for Of course the calcula-

of the other formulae

calculations for three-wire systems.

tion of a three-wire system could be

made

as

if

it

were a two-wire

number of lamps supplied, at system, by taking one-half the total one-half the voltage between the outside conductors. It is

understood, of course, that the size of the conductor in is the size of each of the two outs de ones; but, inasmuch

Formula 6

as the Rules of the National Electric Code require that for interior wiring the neutral conductor shall be at least equal in size to the outside

conductors,

it

conductor.

It

is

not necessarv' to calculate the size of the neutral

must be remembered, however,

that, in a three-wire

system where the neutral conductor is made equal in capacity to the combined size of the two outside conductors, and where the two outside conductors are joined together, we have virtually a two-wire system arranged so that it can be converted into a three-wire system In this case the calculation is exactly the same as in the case later. of the two-wire circuits, except that one of the two conductors is split This is frequently done into two smaller wires of the same capacity. and where are the where isolated plants installed, generators are wound for 125 volts

and

it

may

be desired at times to take current from an

outside three-wire 125-250-volt system.

38

ELE(jriUC WIRING

MliTMOI) Tlif ln>i

wirinj;

it)

>iij)

PLANMNd

A INSIAI.LAIION

Ol-

and

These data

tin-

W

IkMNO

planiiinj; a wiring iiistallati<»n,

wiiirii will allVct fillu-r dirfctly

llif (lata

29

maiiiiiT in wliicli

Kind

will iiulude:

tjic

or

to ^'atlier all

is

iiidiri-ctly

tlu'

.system of

coiKluctors are to

U*

installed.

of l)uildin
(jf

Wuilding;

space available for conductors; s«jurce and systenj (jf electric-current supply; and all details wlii'li will determine the method of wiring to Ir' employetl.

These

last

items materially

all'ej-t

the cost of the

work, and are usually deterniini'd hy the character of the huilding and i)y commercial considerations. jMcthod of Wiring. In a mo
system of wiring

are installed in rigid conduits; although, even

in

such

ca.ses,

it

mav be

and economy may Ije effected thereby, to install the larger and main conductors e.\jK).se
desirable, feetler

slow-burning wire.

This

method should be

latter

however,

u.sc
only where there is a convenient runway for the conductors, so that they will not be crowde
many bends

should be consultitl before

For

.Mso, the local inspection authorithis metluxl.

usiiij;,

mills, factories, etc., wires e.\jK)seil

on cleats or insulators

are usually to be recommende
finishe
buililings,

and

for

extensions of existing

i»utlets,

where the wiring could not readilv or cniivenientlv be concealetl. moulding is generally u.se«|, particularly where cleat wiring or other ex|»osed

methixls of wiring would be objectionable. However, as shoidd not Ih' .said, moulding emplovnl when* therv

has alri-ady Iwen is

any

liability to

dampness.

In finished buildings, particidarly where they are of frame coiistniction, flexible steel conduits or arinore
mende
While

when* the

(|uestioii of first cost is of jirinic ini|M)rtance.

cable will cost approximatciv

.'id

(o |(M(

30

\Vhilearmonil

per cent mon." than

knob and

ELECTRIC WIRING

30

tube wiring, the former method so

much

safer that

it is

so

is

much more permanent and

strongly recommended.

is

— —

Systems of Wiring. The system of wiring that is, whether is usually deterthe two-wire or the three-wire system shall be used If the source of supply is an isolated the source of supply. mined

by

two-wire generators, and with little possibility plant, with simple of current being taken from the outside at some future time, the

be laid out on the two-wire system. If, wiring in the building should isolated plant is three-wire (having three-wire

on the other hand, the

with balancer sets), or if the curgenerators, or two-wire generators rent is taken from an outside source, the wiring in the building should

be laid out on a three-wire system. It very seldom happens that current supply from a central station is arranged with other than the three-wire system inside of buildings, the outside supply is alternating current, the transformers are usually adapted for a three-wire system. For small buildings,

because,

if

on the other hand, where there are only a few lights and where there would be only one feeder, the two-wire system is used. As a rule, however, when the current is taken from an outside source, it is best to consult the engineer of the central station

supplymg the current,

As a matter

of fact, this should be

and to conform with his wishes.

order to ascertain the proper voltage for the done in any for the motors, and also to ascertain whether the central lamps and event, in

station will supply transformers, meters,

and lamps

—

for,

if

these

are not thus supplied, they should be included in the contract for the

wirmg. Location of Outlets.

It is

not within the scope of this treatise

to discuss the matter of illumination, but

it is

desirable, at this point,

method of procedure. including elevation and details,

to outline briefly the

A

if set of plans, any, and showing decorative treatment of the various rooms, should be obtained careful study should then be made by the from the Architect.

A

Owner, and the Engineer, or some other person qualified make recommendations as to illumination. The location of the

Architect, the to

depend: First, upon the decorative treatment of the room, which determines the aesthetic and architectural effects; second^ the type and general form of fixtures to be used, which shoula outlets will

upon

be previously decided on;

third,

40

upon the

tastes of the

owners or

FLECTUic wiiiixn occupiUits

ill

to illiiitiiiiatiuti

rt'ijaril

tastes van* widciv in rf^anl to ainoiiiit

The at eaih.

location of the outlets,

having

in

:n

jjcntTal, us

and

ami the

it

is

fouiul that

kiiul of illiiiiiiiiation.

iiuiiiImt

(»f

li^'hts re<|uire«i

iH^en (leteniiinnl. iht- outlets shuultl Ik*

marked on

the j)laMs.

The

Architect should then

Im.-

consulted as to the hx-ation of

tiie

centers of distriliution, the available jM)ints for the risers or fettlers, ami the available space for the branch circuit coinluctors.

In re<;ard to the rising fMint.s for the ftcdrr.t and mahut, the

fol-

lowing precautions shoidd Ik- useil in selecting chases: 1. The space sliould be amply large to acfomriodate all (lie feeders and mains lik«ly to rise at that j;ivcn f)oint. This seems trite and unii' but it is the most usual trouble with tha-ses for risers. Foniierly a; ...; and builders paiil little attention to the refiuirements for chjuses for electrical work; but in these later days of 2-incii and 2i-inch conduit, they realize that these pipes are not so invisible and mysterious jis the force they serve to distribute, particularly when twenty or more such conduits must be stowed away in a buihliiiR where no special provision hits been made for them. .s

If

2.

possible,

the space should be devoted solely to electric wiring.

objectionable on account of their tem|)erature; and these and all other i)ipes are objectionable in the same space occupied by the electrical conduits, for if the sjjace i)roves too small, the electric conduits are the first to

Steam

Ik*

pi|)es are

crowded out.

The chase, if possible, should be continuous from the cellar to the roof, This i.s neces.sary in ortler to avoid unnecessary bends or or as far as needed. elbows, which are objectionable for

many

reasons.

In .similar manner, the location of

c(//-<
cabintfs or ditlrihuling

centers .shoidd fulfil the following re(|iiirements: 1. They shoukl be jicce.ssible at all times. 2. They should be |)laced sufTicienily do.se together to prevent the circuits from being too long. 3. Do not place them in too prominent a position, as that is obje<*tionable from the .Architect's point of view.

4.

They should be

placeil as near

a.s

po.s.sible

to the

risking

ch.'uses. in

order to shorten the feeders and mains supplying them.

Having determiiHMl the .system and meth(Hl of wiring, the l(H-ation and distributing centers, the next step is to lay out the liranch

of outlets

cirruil.H sup|)lyiiig tlu'

Heforc starling

various outlets.

out the branch ciniiits, a drawing sh«»wing and showing the space In'tween the top of the

to lay

the floor construction,

JM-ams and ginlersand the flooring, should Im* obtitineil fmiii the Architect. In f -proof buildings of iron or sl«'el constnK'tion. it is almost the invariable jmicticc, where the W(»rk

41

is

to Ik* co^lX'all^l, to

nin


ELECTRIC WIRING

32

conduits ove^ the beams, under the rough flooring, carrying them between the sleepers when running parallel to the sleepers, and notch-

when

the conduits run across them (see Fig. 31). In buildings, the conduits run parallel to the beams and to the furring (see Fig. 32); they are also sometimes run below the

ing the latter

wooden frame

Finished Floor^ Kii^mmm^ss^i^^xm.'iiii'i^j^sMfZ'mss&mssms^^^mim!^^^^

JRoia.gh Flooring/

Fig.

31.

Running Conductors Concealed under Floor

in Fireproof Building:.

beams. In the latter case the beams have to be notched, and this is allowable only in certain places, usually near the points where the beams are supported. The Architect's drawing is therefore necessary in order that the location

and course of the conduits may be indicated

on the plans.

The number

first

consideration in laying out the branch circuit

of outlets

The

circuit.

"no

and number

Rules of

is

the

be wired on any one branch the National Electric Code (Rule 21-D) require of lights to

lamps requiring more than GGO watts, whether grouped on one fixture or on several fixtures or pendants, will be dependent on one cut-out." While it would be possible to that

set of incandescent

circuits supplying more than 660 watts, by placing various cut-outs at different points along the route of the branch circuit, so as to subdivide it into small sections to comply with the rule, this

have branch

method

is

not recommended, except in certain cases, for exposed wiring As a rule, the proper method is to have the

in factories or mills.

cut-outs located at the center of distribution, and to limit each branch

660 watts, which corresponds to twelve or thirteen 50-watt twelve lamps, being the usual limit. Attention is called to the fact that the inspectors usually allow 50 watts for each socket connected circuit to

to a branch circuit; and although 8-candle-power lamps may be placed at some of the outlets, the inspectors hold that the standard lamp is approximately 50 watts, and for that reason tb*?"? is always

the likelihood of a

lamp

of that capacity being used,

42

and

their inspec-

KLECrUIC WIHIXG tion

is

Imstil

rt*<|uirfnR'iits,

mi that assumption. Tlierefore, to t-omply with the an allowance of not more than twelve himps j>er hranch

circuit .shoultl Ix"

still

33

made.

In onlinarA- practice, howcscr, it is best to reduce this number fur'licr, so as to make allowance for future extensions or to increase

For this the nuniher of lamjjs that may he j)lacetl at any outlet. it is wise to keep the numljer of the outlets on a circuit at the

rea.son,

It has iK-en lowest p)int consistent with econ(»mical wiriniij. pmven that the best results are obtaine«l by limitinj; the actual practice, by

nunil>er to five or six outlets on a branch circuit. all

the outlets have a .single

rea.sons of

some

to increase

economy,

ca.ses,

each,

it

is

miml)cr

tiiis

Of

course, where

fre(|uently nece.ss5ir\", for ti»

ei<jht,

ten, and, in

twelve outlets.

Wv have already This

lijjht

(|uestion

is

referred to the location

f;enerally settlwl

tion of the building'.

by the

It is nece.s.sarj'

laving out the circuit work, as

it

to

ot"

the wires or conduits.

peculiarities of the constnic-

know

this,

however,

In'fore

frecjuently determines the course of

a circuit.

Now, as

is

it

as to the course of the circuit work,

little nee
Im?

.said,

largely influenced by the relative position of the outlets, cut-

Nv-

Ksi.£r-'

tr.-,-

i

.f-

Wooden stud or

—

-

BecAii.

•ing

Furring Strips

Wall

:bel

Lathing

I'l^;. s-s

Jtfr

^

lUiuuluf Comluclors ConoeaUM undor Floor In WotHlcu

Hetwfi'U the cut-out box and the

outs, switches, etc.

iH'tween the outlets,

the circuits

.shall

it

will

havi- to

l)e

Framo

first

Uuiiaiiit;,

outlet,

diiidiil, however,

and

whether

nin at right angles to the walls of the buiKling or .shall run direct from one point t(» another,

HKnn, or whether they irn"s|K'ctive cours<',

what

ill

less

of the angle they

make

to the sli-eiwrs or U-am.s.

advantages are that the cost is numlK-r of cIIkiws and Ik-iuIs is nxlucetl.

Of

the

latter case, the

.s
and

(In-

If the

43

ELECTRIC WIRING

34

tubes are bent, however, instead of using elbows, the difference in cost is usually very slight, and probably does not compensate for the

disadvantages that would result from running the tubes diagonally. As to the number of bends, if branch circuit work is properly laid out and installed, and a proper size of tube used, it rarely happens is any difference in "pulling" the branch circuit wires. in the event of a very long run or one having a large happen, may number of bends, that it might be advisable to adopt a short and

that there

It

most

direct route.

Up made

to this time, the location of the distribution centers has

been

solely with reference to architectural considerations; but they

must now be considered It frequently

on the plans, we distribution

groups

may

in

happens

conjunction with the branch circuit work. that, after

running the branch circuits

find, in certain cases, that the position of centers of

may be changed to advantage, or sometimes certain be dispensed with entirely and the circuits run to other

We now

wisdom

of ascertaining

from the Architect

where cut-out groups may be located, rather than

selecting particular

points.

see the

points for their location.

As a branch

rule,

wherever possible, it is wise to limit the length of each 100 feet; and the number and location of the dis-

circuit to

tributing centers should be determined accordingly. It may be found that it is sometimes necessary and even desirable to increase the limit of length.

One

instance of this

hall or corridor lights in large buildings. in

may

be found in

It is generally desirable,

such cases, to control the hall lights from one point; and, as the of lights at each outlet is generally small, it would not be

number

economical to run mains for sub-centers of distribution.

Hence,

nms will

frequently exceed In the great majority of cases, however, the best the limit named. results are obtained by limiting the runs to 90 or 100 feet.

in instances of this character, the length of

There are several good reasons for placing such a limit on the length of a branch circuit. To begin with, assuming that we are going to place a limit on the loss in voltage (drop) from the switchboard to the lamp,

it

may be

easily

more economical centers and shorter branch limit

it

longer

is

circuits.

proven that up to a certain reasonable have a larger number of distributing

to

circuits,

than to have fewer centers and

It is usual, in the better class of

44

work, to limit the

ELECTRIC WIRING loss in

V()lta>,'»'

in

anv Ijianth

<

ircuit to a|)|)rit\iinat('ly

suniinf^ this limit (one volt loss),

nuinl)er of

lijjhts

at

one

outlet

circuit 1(X) feet long (using ca.se of outlets

on the

necte
35

it

can

rtMilily

which may

NO.

having a single

i^

1

I

t.^

l»e

nnr

A.v

volt.

calcnlati-il (hat the

l»c'

on a hrancli

conne<-te(|

S. wire), is four;

light each, five outlets

or

may

in the

l»e

con-

circuit, the first In-ing tlO feet frcrn the cut-<jut, the others

U'ing 10 feet apart.

These

e.xaniples are selecteil sini[)ly to

show

that

if

much

longer than KM) feet, the loss must one to more than volt, or else the numl)er of lights that

circuits are

must

the hninch

l)e

increa.si-*!

may

Ih*

con-

a verj' small ijuantity, pnjlie reduced nectcil to one circuit of wire the .sjime. of the size the remains videil, course, to

Either of these alternatives

is

objectionable

— the

first,

on the

and the second, from an economical standp>int. in a branch circuit with all the lights tunie
score of regulation;

numlKT lamp

This, of course, will cau.se the

burn below candle-power when all the lamps are turne
or else it is

of lights burning at a time.

to

the only

lamp burning on

the branch circuits

is

the circuit.

Then,

if

too,

the

drop

in

increa.scd, the sizes of the feeders and the mains

must be correspondingly increased

(if

the total loss remains the .sjune),

thereliy increasing their cost. If the

to go
)f

mimber

of lights on the circuit

is

decreasc
we do

not

u.se

available carrA'iiig capacity of the wire. advantage cour.se, one solution «(f the problem would Ik* to increase the th»'

branch circuits, thus n'ducing the »lrop. This, however, would not be desind)le, except in certain cases where there were a few long cin nils, >u( li as for corridor lights or other six^-ial

size of the wire for the

ontrol circuits.

In such instances as these,

it

increase the sizes of the bninch circuit to NO.

H. )f

&

wouM

be U'ttcr to

12 or even No.

10

fiauge condu<'(ors, than to incn-asc the numU'r of «vnters distribution for the sjikc of a few circuits only, in order to rt
the nnmlK-r of lam|)s (or loss) within the limit. The melhiKl iif calcidating the loss in conductors has Ikhmi given ol.sewheir; but it must br lM»rne in mind, in cjdculating the lo.ss of n

branch

circuit

supplying mon- than one outlet, that

•is

.sej^inite calcu-

ELECTRIC WIRING

36

must be made for each portion of the circuit. That is, a calculation must be made for the loss to the first outlet, the length in this case being the distance from the center of distribution to the first lations

outlet, circuit.

and the load being the total number of lamps supplied by the The next step would be to obtain the loss between the first

and second outlet, the length being the distance between the two outlets, and the load, in this case, being the total number of lamps supminus the number supplied by the first outlet; plied by the circuit, and so on.

The

loss for the total circuit

would be the sum of these

losses for the various portions of the circuit.

Feeders and Mains.

On

If the building is

more than one

story,

an

the height and number of stories. this elevation, the various distributing centers should be shown

elevation should be

made showing

diagrammatically; and the current in amperes supplied through each center of distribution, should be indicated at each center. The next step is to lay out a tentative system of feeders and mains, and to ascertain the load in amperes supplied by each feeder and main.

The

estimated length of each feeder and main should then be deter-

mined, and calculation made for the loss from the switchboard to each center of distribution. It may be found that in some cases it will be necessary to change the arrangement of feeders or mains, or even the centers of distribution, in order to keep the total loss from the switchboard to the lamps within the limits previously determined.

As a matter of fact, in important work, it is always best to lay out the work tentatively in a more or less crude fashion, according to the "cut and dried" method, in order to obtain the best results, because

entire

the entire layout

may be Of

has been made.

modified after the

first

course, as one becomes

skilled in these matters, the final layout is often

the

first

preliminaiy layout

more experienced and almost identical with

preliminary arrangement.

TESTING Where

possible,

two

tests of the electric

be made, one after the wiring

itself is entirely

wiring equipment should

completed, and switches,

cut-out panels, etc., are connected; and the second one after the The reason for this is that if a ground fixtures have all been installed. or short circuit

more

easily

is

discovered before the fixtures are installed,

remedied; and secondly, because there

46

is

it

is

no division

oi

KLECrUIC WIUING the

re.sjM)nsil)ility,

after the fixtures

as there might

were

the

lie if

were made only sliows no gnninds or

first test

If the test

installe
37

short c-ireuits l)efore the fixtures are installetl, and one does develop after tliey are installetl, the troulde, of course, is that the short circuit

or i:n)un(l

is

one or more of the

fixtures.

As a matter

of fact,

it is

wise plan always to make a separate test of each fixture after deliverctl at the huilding and l>efore it is installnl.

it

a is

While a magneto is largely used for the pur|)ose of testing, it is and unreliable niethcxl. In the first place, it does not give an indication, even approximately, of the total insulation

at liest a cruile

resistance, but merely indicates circuit, or not. let!

In

some

whether there

to serious errors, for reasons that will

it

may sometimes happen

—

test

magneto

he cxplainetl.

If,

-

has

as

is

an alteniating-current instruparticularly in long cables, and

nearly always the case, the magneto

ment,

a ground or sliort

is

instances, moreover, a

is

—

a lead sheathing on the cable that the magneto will ring, indicating to the uninitiated that there isa gn)unti or short circuit on the cable. This may l)C, and usually is, far fn)m

especially

where there

is

being the case; and the cause of the ringing of the magneto is not a ground or short circuit, but is due to the capacity of the cal)le, which acts as a condenser under certain conditions, since the magneto pnxlucing an alternating current repeatetlly charges and discharges the cable in opjKtsite directions, this changing of the current caiising the magneto Of course, this defect in a magneto could be lemedietl by to ring.

using a commutator and changing it to a dirc(t-
A

portable (jalvanomeicr with a resistance Ih)X and \\heat.stone bridge, is .sometimes employnl; lii;( this nictluxl is objectionable Ix'cau.se it requires a sju^cial instniment which cannot U> useil for

nmnv to

othtT |)uqH).ses.

Furthermore,

it

The advantage

of the voltmeter

more

rc<|uin's

use than the voltmeter meth(Kl, which will

method

now U* is

that

skill

and time

descrilHsl. it

merely other puiixises, and which all engineers or contractors should |k>ss<'ss, together with The v«»lta l)ox of cells having a {K)tential of preferably oxer 'M volts. H dircct-iurrcnt voltmeter,

which can U-

meter shot dd have n scale of not over the scah" 1,()(H)

«»n

whicli the battery

volts) the n*adings

might

47

covers

rtHpiires

many

l.V) volts, for

is u.se»| Ik> .so

ustil for

t
small as to

the reason that

wide a nmge

make

the

te.st

if

(sjiy

inac-

ELECTRIC WIRING

38

A

curate.

two

scales

arrangement would be to have a voltmeter having and one of 600 which would make the

—good one of 60 say,

voltmeter available for

—

all practical potentials

that are likely to be

used inside of a building. If desired, a voltmeter could be obtained with three connections having three scales, the lowest scale of which

would be used for testing insulation

resistances.

Before starting a test, all of the fuses should be inserted and switches turned on, so that the complete test of the entire installation can be made. When this has been done, the voltmeter and battery should be connected, so as to obtain on the lowest scale of the volt-

meter the electromotive force of the entire group of cells. This is shown in Fig. 3.3. Immediately after this has been done, the insulation resistance to be tested

connection

is

placed

in

whether the

circuit,

insulation to be tested

board,

slate

a switch-

is

made

connections are 34.

should

and the leakage Connections of Voltmeter and Battery for Testing Insulation

is

the

and the

shown

as

A

reading again be taken of the Fig.

or

panel-board,

entire wiring installation;

in

then

voltmeter;

in

proportion to the difference between the first

33.

Fig.

Resistance.

and second readings of the meter.

will

show how

this resistance

the resistance in the

first

case

may be

The

calculated

was merely the

meter and the internal resistance of the battery.

:

this will

be done

It Is evident that

resistance of the volt-

As a rub,

resistance of the battery is so small in comparison of the voltmeter and the external resistance, that

neglected, and

volt-

explanation given below

x^^ith

the internal

the resistance

may be

entirely

in the following calculation.

In the

it

second case, however, the total resistance in circuits is the resistance of the voltmeter and the batter}-, plus the entire insulation resistance

on

all

the wues, etc., connected in circuit.

To

put this in mathematical form, the voltage of the cells may be indicated by the letter E; and the reading of the voltmeter when the Insulation resistance

Let R represent

is

connected by the

circuit,

the resistance of the voltmeter and

insulation resistance of the installation

48

by the

Rx

which we wish

letter E'.

represent the to

measure.

Ei.Kr'Tiac wiiiixG It is

a fact

wliicli

the nnuler

uiul(Jiil)te
•'.')

knows, that the K. M.

F. as

hy the voltmeter in Fifj. 3-4 is inversely proportional to the resistance: that is, the greater the resistance, the lower will l>e the indicatetl

reatling

on the voltmeter, as

reading indicates the leakage or cur-

this

rent passing thn>ugh the resistance. Putting this in the shape of a formula, we have from ilie theor}* of proportion: /•:

K'

:

::

li

+ U,

W

:

;

or,

E'

+

li

Transposing, E' lix

K' lix

- E

-

li

R.

-- i:

E'

n=

li

{E-E'),

an
Rx

= R{E-E') E'

expres.sed in wortls, the in.sulation resistance is ecjual to the resist-

Or, ance of

the

volt-

meter 7nultipllcd hy the

(lifTerence

tween the

l->e-

first rea
ing (or the voltage in

the

cells)

and Bu3

the .second reading (or the

reading of

>-Bua

the voltmeter with the

insulation

34.

Fig.

lu.sulatlou

Ut.-!.l.-.t;iuco

I'laceU lu Circuit, l{o;iJy

|.

r

Testing.

re-

sistance in series with the voltmeter), divided by this last reading of the voltmeter.

Example. A.s.sume a resistance of a voltmeter (/?) of 2(1.(HK) ohms, and a voltage of the cells (E) of 30 volts; and suppo.sc that the insulation

rcsistatue test of a wiring installation, including switchlM>ard,

feetlcrs,

hramch

ciniiils, j)ancl-l)oarils, etc.,

is

to

tion resistance U-ing reprcst'iited l>y the letter

he mailc, the insula/i

j.

.

Hy

suhstituting

in the forniiila

R (E -

,,

and

a.vsuining

tiiat

tin-

E')

reading of we have:

tin-

voltmcttr with

tlic

insidation

n'sistjince conne<'te
"

•JO,(KMI

".)

, •

ll

tin

ic.sl .-allows

an

-

l(K),(M)OolilllK.

»

excc'.ssive ainoui>l of h'akag**,

40

or a groinul or

ELECTRIC WIRING

40

may be determined by

short circuit, the location of the trouble

—

the

process of elimination that is, by cutting out the various feeders until the ground or leakage disappears, and, when the feeder on which the trouble exists has been located, by following the same process

with the branch

circuits.

course, the larger the installation and the longer and more numerous the circuits, the greater the leakage will be; and the lower

Of

will

be the insulation resistance, as there is a greater surface exposed The Rules of the National Electric Code give a sliding

for leakage.

scale for the requirements as to insulation resistance,

the

amount

etc.

The

depending upon by the various feeders, branch circuits, of the National Electric Code (No. 66) covering this

of current carried

rule

point, is as follows: in any building must test free from grounds; i. e., the commust have an insulation between conductors and between conductors and the ground (not including attachments, sockets, recepta-

"The wiring

plete installation all

not less than that given in the following table: 5 amperes 4,000,000 " 10 2,000,000 " 25 800,000 " 50 400,000 " 100 200,000 " 200 100,000 " 400 50,000 " " 800 25,000 " " 12,500 1,600

cles, etc.)

Up

to

uhms " " " "

"

" " "

test must be made with all cut-outs and safety devices in place. If sockets, receptacles, electroliers, etc., are also connected, only onehalf of the resistances specified in the table Avill be required."

"The

the

lamp

ALTERNATING-CURRENT CIRCUITS not within the province of this chapter to treat the various alternating-current phenomena, but simply to outline the modifications It is

which should be made wiring, in order to

in designing

and calculating

make proper allowance

electric

light

for these

phenomena. The most marked difference between alternating and direct cur-

rent, so far as

wiring

induction, which

This

is

concerned,

is

the effect produced by self-

characteristic of all alternating-current circuits. self-induction varies greatly with conditions depending is

upon

the arrangement of the circuit, the medium surrounding the circuit, the devices or apparatus supplied by or connected in the circuit, etc.

50

ELErnur WIRING For

exainpli",

tlie

circuit, a current of

a

if

might

a resistant-e of KM)

ohms

iiuludetl in

is

ampere can Ix? passotl through the c-oil KM) of vohs, if direct current is use«l; wliile pressure

with an electric it

ti)il liii\ iiig

41

«)iie

of several luuulretl volts to re<|uire a jK)tential

pass a current

altenuiting-
of «Mie

if

non-magnetic material, etc. It will l)e seen from this example, that greater allowance shouKl be made for self-inducti(»ii in laying out and calculating alteniatingcurrent wiring,

be

if

the conditions arc such that the self-induction will

aj)precial»le. (

accovmt of self-induction, the two wires of an alteniatingIk? installed in separate in»n or stivl con-

)n

current circuit must never duits, for the reason that

such a circuit would

consistini: of a sinirlc tuni of wire

wound on an

l)e

virtually a choLr coil

iron core,

and the

self-

induction would not only reduce the current passing through the cirIt is for this cuit, but also might prinlucc iieating of the iron pijx-*.

reasfm that

National

t\\e

/'^/cc/r/cCw/p rc(|uircs conductors constitut-

ing a given circuit to be placed in the same conduit, if tluit conduit is iron or steel, whenever the said circuit is intended to carrA', or is liable to carry at

some

futur? time, an r.lternating current.

This dmvs

not mean, in the case of a two-phase circuit, that all four conductors nec
should be placed

in the

siime conduit, as .should also

Ik-

the ca.sc in a

( )f cniirM', in a three-wire three-phase system. single-pha.se two- or three-wire .system, the conductors should all be placnl in the .sjune

ti^ndiiit.

In calculating circuits carrAiiig alternating cnrrciit, no alltiwance u.->uallv

should

Ik

made

for s«'lf-induction

when

the conductors of the

.same circuit are place
nm

other, calculation should

In-

made

to

determine

if

the elTects

»)f

.self-

induction are great enough to «ause an apprevend metlnnls of calculating this droj» «lue to .self-induction Ix'

—one bv formula, an
mathematical metluMl which

de.scrilK'd.

61

will

ELECTRIC WIRING

42

Skin efFect in alternating-current circuits

Skin Effect.

by an incorrect distribution of the current

is

caused

in the wire, the current

of the wire, it being a welltending to flow through the outer portion known fact that in alternating currents, the current density decreases

toward the center of the conductor, and that in large wires, the current small. density at the center of the conductoris relatively quite eter,

The

skin effect increases in proportion to the square of the diam-

and

also in direct ratio to the frequency of the alternating current. S. Gauge, and smaller, and for conductors of No. 0000 B.

For

&

or less, the skin effect frequencies of 60 cycles per second, and is less than one-half of one per cent.

is

negligible

For very large cables and

for frequencies above 60 cycles per be may appreciable; and in certain cases, allowin be made should making the calculation. In ordinary

second, the skin effect

ance for

it

practice, however,

it

may be

neglected.

Table IX, taken from

Alter-

nating-Current Wiri7ig and Distribution, by W. R. Emmet, gives the

data necessary for calculating the skin effect. The figures given in the first and third columns are obtained by multiplying the size of the conductor (in circular mils) by the frequency (number of cycles per second); and the figures in the second and fourth columns show the factor to be used in multiplying the ohmic resistance, in order to obtain the combined resistance and skin

TABLE

effect.

IX

Data for Calculating Skin Effect Product of Circular Mils

X Cycles per

Sec.

ELECTRIC WIRIXG

43

nuitual iiitluction takes place. The amount of tliis iiulucetl K. M. F. ill one circuit by a parallel current, is dejH-nilent u|K)n the cur-

set

up

rent, the fre<|uency, the leiij,'ths of the circuits runniiifj; parallel to

other, s;iid

and the

ri-lative

each

positions of the conductors constituting

tlje

circuits.

I iider onlinary conditions, and except for long circuits carrying high jMttentials, the elYect of nuitual induction is .so slight as to be In onlcr negligible, unless the conductors are iinj)ro[)erly arninged.

to

a given prevent nuitual induction, the conductors constituting

circuit should l)e groupeil together.

o o

o o

to 31), inclusive,

.035 Volts,

Alt.

.016 Volts.

35.

16,000 Alt.

.015 Volts.

Alt.

.0065Vo1ts.

16,000

Alt.

.070 Volts.

7200

Alt.

.032 Volts.

le^ooo Alt. 7200 Alt.

.0027 Volts,

7200

o

36.

O Fig.

37.

o Fig.

lepoo

Alt.

7^00 Alt Fig.

arrangements of two two-wire

arrangc
arninged, as

a piil)lication

miiitum,

Volts.

.CSO Volts,

circuits;

(ilvliig

and show how

Vurlous

relatively

of first induction is when the conductors are j)n)iHTly Fig. .'{S, and how relatively large it may Ik- when im-

small the effect

j)ri>perlv

MS

39.

Various Groupings of Conduciors In Two Two-Wlro Circuits, KtlecU of Uiiluotioii.

five

.006 Volts.

38.

o

o

show

l€)00O Att.

7200 Fig.

Fig.

o

.3.j

Tigs.

of

i.ssue
in

Fig.

Mr. Charles by

the

Thcs«' diagrams are taken from

'^*^.

F,

Scott, enfitletl

Westinghou.se

I'lectric

Pohiphasf Traus-

&

Manufacturing

Companv.

The clTc< of capacity is usually negligible, lines where high |M)tcntials art* u.s»\l; no tnmsmi.ssion long except calculations or allowance need Im- made for capat'itv, for ortlinar>' Line Capacity.

t

in

circuit.H

53

ELECTRIC WIRING


Calculation of Alternating=Current Circuits.

In the instruction

paper on "Power Stations and Transmission," a method is given for calculating alternating-current lines by means of formulse, and data are given regarding power factor and the calculation of both single-phase

For short lines, secondary' wiring, etc., howmore convenient to use the chart method devised ever, probably D. Mr. Mershon, described in the American Electrician of Ralph by and June, 1897, partially reproduced as follows:

and polyphase

circuits.

it is

DROP

ALTERNAT1NQ=CURRENT LINES

IN

When alternating currents first came into use, when transmission distances were short and the only loads carried were lamps, the question of dro'p or loss of voltage in the transmitting line was a simple one, and the same methods as error be

employed

alternating

for direct current could without serious

in dealing with

— to-day longer

practice

it.

The

conditions existing in

distances,

polyphase

circuits,

—

and loads made up partly or wholly of induction motors render this question less simple; and direct-current methods applied to it

do not lead

to satisfactory'

results.

if it is

Any

treatment of this or of

to benefit the majority of engineers,

any engineering subject, must not involve groping through long equations or complex diagrams The results, if any, must be in availin search of practical results. In what follows, the endeavor has b?en

able and convenient form.

made if it

to so treat the subject of

drop in alternating-current lines that the reader be grounded in the theor}' the brief space devoted to will suffice; but if he do not comprehend or care to follow the

simple theory involved, he

may

nevertheless turn the results to his

practical advantage. Calculation of Drop.

Most

of the Hiatfer heretofore published

on the subject of drop

treats only of the inter-relation of the E.

M.

F.'s

involved, and, so far as the writer knows, there have not appeared in convenient form the data necessarj' for accurately calculating this c(uantity.

X

Table

(page 47) and the chart (page 46) include, in a

form suitable for the engineer's pocketbook, everj'thing necessary for calculating the

The

chart

is

drop of alternating-current lines. simply an extension of the vector diagram

giving the relations of the E.

M.

F.'s of line, load

54

(Fig. 40).

and generatoi.

In

KI.K("ri:it' \V!i;!\T,

Fif;. -10, A'

is

the gfru-ratur K.

M.

c, that conijM)neiit of /•' (Uie to the impeilance of the Uiic.

the lu;ul

;

1'.;

e,

the E.

45

M.

F, iinpresstil

which overcomes the hack

The

coni|xjnent c is

1*2.

upon

M.

F.

made up of two

components at rijjht aiif^les to eacli other. One is a, tlie comjKJuent overcoming the III or hack !•'. M. 1'. ihic to resistance of the Hue, Tlie other is h, the component overcoming the reactance E. M. F. or hack E. M. F. (hie to the aUernating field set up anjund the wire hy "^I'he the current in the wire. drop is the ilill'crcnce iK-tween K ami It is

e.

is

the ratlial ilistance l)etween two circular arcs, one of which

(/,

drawn with

The as a

The

a radius

ce n

e

t

c,

and the other with a radius E.

maile by striking a succession of circular arcs with

cliart is

v

r.

the

radius of

smallest circle corres|K)nds to e, the E. M. F. of the load,

as

which

100

is

taken cent.

per

The radiiof the succeeding circles increase by 1 per cent of that of the smallest circle;

the

and, as

radius of

the

--d --J

or largest circle is 110 j)er cent last

Fig.

iO.

Vector Diagram.

of that of the smallest, the chart answers for drops uj) to 10 jxr cent of the E. M. V. delivere
The

tenns

ing the back

The

K.

rcsittaiicv rolls, rr.si.stanrr

and uarlancc K. M. 1',.

M.

M.

/•'.,

mirtanci' ivlts,

refer, of course, to ihc voltages for

/•'.,

I'.'s

due

lo resistance

figures given in the table

for Onir .\m[M're, etc." are

and reactance

oven-om-

respectively.

under the heatling "Hesistaiice-Volts

simply

tin*

resistances of 2,0(K)

fe«-t

of the

The

values given under the heading "Kea«tance-\'olts, etc.," are, a part of ihem, calculatnl-fntm tables ]iublished simw time agr) by Messrs. Houston and Keimelly. The remainder various sizes of wire.

were obtained by using Maxwell's fonnula.

The

explanation given

in

the

56

taltle

ai-companying the chart

ELECTRIC WIRING

46

•

T

,8

LOAD POWER FACTORS

O

.9

DROP

IN

lO PERCENT OF

20 E.tt.F.

Chart for Calculating Drop in Alternating-Current Lines.

56

OEUVEREO

30

ELECTRIC WIRING

47

TABLE X Data for Calculating Drop To

be

u-.<xl 111

In Altcrnatinjj-Currcnt

iiiDjumtl.iii Willi I'liart i>u ojjjx.iUt!

i> '••'•' •'tbie, palculat« the /?'»J<..wirtat.i..r ..r 11.. 1...1.1 111'.t tluis K. M. K. h<>rl/...m;illv iiiid

Lines

put;
/.'.i •fjri.

.•

I'.f'i

In the

^.

...o

F

'

•

1.

...

,

M. K. •

.

...

.,,..,

ili'llvi.rfil

lit ilr.ii) •<>

:ii

whlih

It

.

ttu< t-inl

h

lli«

l;k ..

uf ihe line,

(i)>iiiiW.

,

....

fcvery tvniti circto

ELECTRIC WIRING

48

thought to be a sufficient guide to its use, but a few examples may be of value. Power to be delivered, 250 K.W.; E. M. F. to be delivered, Problem. (Table X)

is

2,000 volts; distance of transmission, 10,000 feet; size of wire. No. 0; distance .8; frequency, 7,200 alterna-

between wires, 18 inches; power factor of load, Find the line loss and drop. tions per minute.

Remembering

that the

power

factor

that fraction by which

is

the apparent power of volt-amperes must be multiplied to give the true power, the apparent power to be delivered is

=312.5 apparent ^^^^•^^.o

The

KW.

current, therefore, at 2,000 volts will be

2,000

From

=^ -^6 .25 amperes.

the table of reactances under the heading "18 inches," and wire, is obtained the constant .228. Bearing

corresponding to No.

the instructions of the table in mind, the reactance-volts of this line

156.25 (amperes) X 10 (thousands of feet) X .228 = 356.3 volts, which is 17.8 per cent of the 2,000 volts to be delivered. From the column headed "Resistance-Volts" and corresponding

are,

to

No.

is

wire,

obtained the constant .197.

The

resistance-volts

X

of the line are, therefore, 156.25 (amperes) 10 (thousands of feet) .197=307.8 volts, which is 15.4 per cent of the 2,000 volts to be

X

delivered. Starting, in accordance with the instructions of the table, from the point where the vertical line (which at the bottom of the chart is marked "Load Power Factor" .8) intersects the inner or smallest circle, lay off horizontally

and

to the right the resistance-E.

M.

F.

in.

per cent (15 .4) and jrom the point thus obtained, lay off vertically the reactance-E. M. F. in per cent (17.8). The last point falls at about 23 per cent, as given by the circular arcs. This, then, is the drop, in ;

per cent, of the E. M. F. delivered. tor E. M. F. is, of course,

23

100+23

The drop,

in

per cent, of the genera^

18.7 per cent.

The

percentage loss of power in the line has not, as with direct same value as the percentage drop. This is due to the fact that the line has reactance, and also that the apparent power

current, the

58

< H.

a z < 3

:.

I

J ^ 5 - - ;« s "l •* * > <

1 fi

^ P S > ^ fr-

|4

I

-J

;;

%-

'r

J*

f

X B o o

o: (J

z

a

Ill

to

(IfliviTttl

the Imul

by

IojmI

is

factor

is

(111-

powtT

<

nut

I'UiC

WIRING with

iilctilical

K-ss tliaii unity.

49

tlu*

'I'lie

tnu- |Ki\ver

loss

what amounts

calculatinfi; /• li for tlic llnr, or,

must

l')("..2r)

amperes.

lo.ss

ij

X

307. S

Ls,

Ik- ul)taiia'(i

to the sjime thing,

by muhiplyinj^ the resistance-voUs by the current. The r»'sistanee-vohs in this case are 307. S, an
The

— tlmt

l'j
1

the current

W.

K,

The

losti is

{HTcentagc

48.

1

...

=

Kj.I,

250+4K.1

per cent. '

Therefore, for the j)rol>lem taken, tlie drop is IS. 7 per cent, an
must

it

tlrop,

l)e solvetl l)y trial.

A.ssume a size of wire anil calculate

the (ln)p; the result in coiujection with the table will show the direction an
The

etVect of the line reactance in increasinj; the

If there

note«l.

were no reactance, the drop

drop

.should

the al)ove

in

l)e

example

given by the point obtained in laying off on the chart the resistance-E. M. F. (15.4) only. This point falls at 12.4 per (rnt, and the drop in terms of the generator K. M. F. would be

would

l>e

12 4

=

11 per cent, instead ot IS. 7 percent. * '

112.4

Anvthini: therefore which will reduce reactance

Reactance can be reduced

in

two ways.

The

diminish the distance l)etween wires. Ih'

carrinl

is

desirable.

is

One

of the.se

is

to

extent to which this can

limited, in the case of a pole line, to the

lea.st

di.^tance at

which the wires are snU' from swinging together in the middle of the span; in irisidi* wiring, liy the danger from lire. The other way of into a greater mimU'r t)f is to split the copj)cr up and arrange the.se circuits so that there is no inductive interVnr instance, supjM)se that in the example work«l out alnAe,

reilncing reactance circuits,

arlion.

two No. 3 wires were volts le.ss

would

Im-

in the nitio J

current the No. instead of i.s

al.so

u.setl

pnictically 211 "

X

-

if

in tin'


one No.

No.

The

example given

59

'i'he :vsislaneeIk*

each circuit would U-ar half the

and the constant 0.

wire,

but the reactan<e-v«ilts wotdd

^ .03'), since

circuit ihx's,

L'L'S— that for

shown

in.stead

tlu' .sjim«-,

it

is

for

No. 3 wire

!.>•

.241,

of .suUlividing the eop|H'r desinxl to retime the drop

elT<'cl

ELECTRIC WIRING

50

to No. 0000 will Increasing the copper from No. not produce the required result, for, although the resistance-volts will be reduced one-half, the reactance-volts will be reduced only in the to, say, one-half.

ratio .212^

however, two inductively independent circuits of No.

If,

.228*

wire be used, the resistance- and reactance-volts will both be reduced one-half,

and the drop

will

therefore be diminished the required

amount.

The component

of drop due to reactance is best diminished by sub-

dividing the copper or by bringing the conductors closer together. is little affected by change in size of conductors.

An drop

is

idea of the best gotten

manner

in

which changes of power factor

Assume

by an example.

It

affect

distance of transmission,

M. F., and frequency, the same as in the previous example. Assume the apparent power delivered the same as before, and let it be constant, but let the power factor be given

distance between conductors E.

several different values; the true power will therefore be a variable depending upon the value of the power factor. Let the size of wire be No. 0000. As the apparent power, and hence the current, is the

same as E.

M.

before,

and the

line resistance is one-half, the resistance-

F. will in this case be

—^, or 7

15.4

.

7 per cent of the E.

M.

F. delivered.

Li

Also, the reactance-E.

M.

F. will be

.212X17.8

^

,.

228

Combining these on the chart

for a

^

P^^

'

power factor

of .4,

and deducing

the drop, in per cent, of the generator E. M. F., the value obtained is 15.3 per cent; with a power factor of .8, the drop is 14 per cent;

with a power factor of unity,

it is

8 per cenl.

If in this

example the

true power, instead of the apparent power, had been taken as constant, it is evident that the values of drop w'ould have differed more widely,

the current, and hence the resistance- and reactance-volts, would have increased as the power factor diminished. The condition taken more nearly represents that of practice. since

If the line

had resistance and no reactance, the several values and 8, would be 3.2, 5.7, and 7.2 per

of drop, instead of 15.3, 14,

cent respectively, showing that for a load of lamps the drop will not

60

ELEmUC l>i>

imicli iiKTrasiil l>y reactaiiii-;

tion inoturs, whosi'

powrr factor

WmiN'G

l)iit

is

51

that with a

the rcactaiici' as low as practicahlt*.

taki'ii to kr<'|)

.siuh a.s iiithu--

li»ati,

niw

than miity,

k-.ss

In

U

.should

all casivs

is

it

place conductors as close to<,'ether as gtKxl practice will

ailvisiihle to

permit.

When

there

a transformer in circuit, and

is

the conihine
and

the resistance-

and

line,

it

desire
it

is

is

necessarj' to

reactance-volts of the transformer.

ance-volts of the combination of line the resistance-volts of the line

know

The

resist-

and transfcjnner are the .sum of

and the resistance-volts of the

trans-

Similarly, the reactance-volts of the line and transfonner are the sum of their respective reactance-volts. The resistance- and

fonner.

M.

usually be obtaiiu'*! fn)m The.M^- \htper cent.* M. F.'s the values of the resi.stanceand reactance-E. centages expre-ss when the transformer delivers its normal /«//-/oaJ current; and they

reactance-E.

F.s of transformers

may

and are ordinarily given

the makers,

in

express these values in terms of the normal no-luad E. transformer.

Consider a transformer

l)uilt for

and reactance-E. M.

volts.

volts or

20 and 70 volts according as the

resistance-

V. of the

Wtween

trans-formation

and KK)

tlie

M.

1,(KX)

E.'s given

Suj)pose are 2 per cent and 7 per cent respectively. Then the corresjx)nding voltages when the tninsformer delivers full-load current, are 2 and 7

connecte
is

values, 2

line whose droj) is re«|uireil the low-voltage or high-voltage terminals. These

to

— 7 and 20— 70, hold,

•Whcn

the ro
.McoMurt) tlir

iMf^oHurc*!.

no matter

n^isiunccof

Iwith

1)0 olttaincvl nill.s.

'Ion the

what voltage the trans-

.

III" r<

rnlcuhiutl

Ih<

till'

Ihj

uitachMf

that of thi

Ihenitloof

' '

mra.Hiir<"
i»

.^

i

|o»-M>U.4Kt' ri.il Moil JH 10. ihe ctiulvalent r<'sisian(t> rrfcrrf"! to the li r the hli;h-voltaKe roil, 100 tinieN that of (he jtlut

I:

tri

may

from tho makers, thry

the linoto

If

to th« lilKh-voltaKe tiTniinuls of thu traiisforiiicr, the hieh-viiHaKO roil. ;'/uj th)< rotlHtancc olxaineil l>y !» '

at

•

•

I

•

of It

I

liy the Mkti mi1Iii(;«« current the hlKh-vo|l;i nvUI.Similarly, the aii> ' rfferrol to tlii< low-volluKe ein'iilt In 1.< .ni'c of Iho low-volt.i. .../xjlhal of lhi< hlKh voltak'i' eoll rtducrd in the w|uareof (he ratio uf (raiwformndon It follown. ''•• tw<» rirrulla of i-ourwv fnitn ttilx. (hat the valiH>Hof the r(«U(ane«>-vo|lH referr'-' hear to eaeh other the ratio of (ran.tformatlon volla. itluirtTo obtain the rlrriili oni- roll of thi< tranAfonuer aii'I lhi< other roil ilN normal ciim'nl at i. -.taiice

e'liiU r<

niiiltlplUol

n-frrnxl

si-.';nnf»-volt(i

t

t
<

\

1

'

\

'

tln> n-iii iaiiii>Mi|i
I

.,••

li

M

In il,i-N

iiM... ,r

nauUa

II..

I..

•

T9*\»tar\(t

If

i

rliMx valii-

<<

\

61

(if

a

iiH«

ELECTRIC WIRING

52

the strength of curoperated, since they depend only upon If any other than the normal of the it is frequency. rent, providing full-load current is drawn from the transformer, the reactance- and

former

is

be such a proportion of the values given above as the current flowing is of the full-load current. It may be noted, in the resistance- and reactance-volts of a transpassing, that when

resistance-volts will

former are known,

its

of the chart in the

regulation

may be determined by making

same way as

for

use

a line having resistance and

reactance.

line

As an illustration of the method of and transformer, and also of the use of

calculating the drop in a and chart calculat-

ing low-voltage mains, the following example Problem.

A

motor

single-phase induction

m

table

is

is

given

:

to be supplied with 20

am-

peres at 200 volts; alternations, 7,200 per minute; power factor, .78. The distance from transformer to motor is 150 feet, and the line is No. 5 wire, 6 inches between centers of conductors. The transformer reduces in the ratio

——

,

when

has a capacity of 25 amperes at 200 volts, and,

delivering this

its resi?tance-E. M. F. is 2.5 per cent, its reactanceFind the drop. The reactance of 1,000 feet of circuit consisting of two No. 5 The reactance-volts therefore are wires, 6 inches apart, is .204.

current

and voltage,

E. M. F. 5 per cent.

1

X

.204

The

'lO

Y^ X 20 =

.01 volts.

resistance-volts are

.627

X -i^ X

20

=

1.88 volts.

1,000

At 25 amperes, the resistance-volts of the transformer are 2.5 per 20 of this, or 4 volts. cent of 200, or 5 volts. At 20 amperes, they are

—

the transformer reactance-volts at 25 amperes are 10, and at 20 amperes are 8 volts. The combined reactance-volts of Similarly,

transformer and line are 8 the 200 volts to be delivered.

+4, or

5.88,

Combining the drop

is

which

is

+

.61

=

8.61, w-hich

The combined

is

4.3 per cent of

resistance-volts are 1.88

2.94 per cent of the E.

M.

F. to be delivered.

these quantities on the chart with a power factor of .78, 5 per cent of the delivered E. M. F.,

or of the impressed E.

M.

F.

—= The

4.8 per cent

transformer must be supplied with

62

ELECTRIC >VIRING ^^^^ =

r,3

2,100 volts,

.952 in

onler that 200 volts shall he

X

Tahle answer

for

in direct

(page 47)

is

«h'livere«l to the inot«»r.

made out

for 7,200 alteriuitions,

j)nij)ortion

.

.

Ifi.iMM)

i'lir

will

if

,

for

hut

the values for n-aetanee be changed For instanc-e, to the change in alternations.

any other nun>l)er

alternations,

,

,

multiply the

reactances given

10,000

,

by

^

uiher distances hetween centers of conductors, interpolate the As the reactance values for diliVreiit sizes

values triven in the tahlc.

of wire change by a constant amount, the tahle can, for larger or smaller conductors. rea
The table is M. r.'s. The

basetl

if

desired, be

on the assumption of sine currents and

which practice of to-day produces machines so closely approximate this condition that results obtaine
Ix^st

single-phase circuits only have A simple extension of the metluHls given al)ove Int'ti dealt witii. A four-wire adapts them to the calculation of polyphase circuits.

Polyphase Circuits.

So

far,

quarUr-phase (two-phase) transmission may, so far as loss and regidation are concenietl, be replaced by two single-phase circuits identical (as to size of wire, distance

between wires, current, and E. M. F.)

with the two circuits of the quarter-pha.se transmission, providt^l that Therein lK)th cases there is no inductive interaction Iwtween circuits. fore, to calculate

a four-wire, quarter-phase transmission, compute

the single-phase circuit recpiirt^l to tr.msmit one-half the jM)wer at The <|Uar((T-j)hase transmission will require two the same voltage.

such

circuits.

A

three-wire, thrvc-phasc transmi.ssion, of which the conductors .so far as lo.ss and n-gulation are

are synnnetrically relalnl, may,

concernnl, be replace
Inmsini.ssion, calculate a

one-half the load at the s;iine vnliage. sion will rc(iiiire three wiii-s of the

si/«'

single-phase- circuit

to

caiTj*

The

thn'c-pha.se transmisand distance U-tween centers

as obtaine«l for the singl«--|)hase. .\

three-wire.

iw()-pha.sc

transmi.ssion

03

may

U-

cal«»iIaU\J

ELECTRIC WIRING

54

exactly as regards loss, and approximately as regards drop, in the same way as for three-phase. It is possible to exactly calculate the drop, but this involves a more complicated method than the

approximate one.

The

error

this

by

approximate method

is

gen-

It is possible, also, to get a- somewhat less erally small. drop and loss with the same copper by proportioning the cross-section of

the middle and outside wires of a three-wire, quarter-phase circuit to the currents they carry, instead of using three wires of the same

The

size.

advantage, of course,

is

not great, and

it

be con-

will not

sidered here.

WIRING AN OFFICE BUILDING The is

that of

building selected as a typical sample of a wiring installation office building located in Washington, D. C. The figures

an

shown are reproductions

of the plans actually used in installing the

work.

The

building consists of a basement and ten stories. It is of beams with terra-cotta flat arches.

fireproof construction, having steel

The main

walls are of brick and the partition walls of terra-cotta with plaster. There is a space of approxnnately five finished blocks, inches between the top of the iron beams and the top of the finished floor, of

which space about three inches was available for running

the electric conduits.

mosaic, or

concrete,

The tile

flooring

the

in

is

of

wood

basement,

in the offices, halls,

but of

toilet-rooms,

etc.

The

electric current

supply

is

derived from the mains of the local

illuminating company, the mains being brought into the front of the building and extending to a switchboard located near the center of the

basement.

As the building is a veiy substantial fireproof structure, the only method of wiring considered was that in which the circuits would be installed in iron conduits.

Electric Current Supply.

The

electric current

sapply

is

direct

current, two-wire for power, and three-wire for lighting, having a potential of 236 volts between the outside conductors, and 118 volts,

between the neutral and either outside conductor.

64

SwitcliboarJ.

(

ELECTRIC \VIRL\G

65

.switch hoanl in tlie

hasement are mounted

tlu-

)ii

wuttmottTs, pnividttl by tlie local t-lfctric connmiiy, aiul U»e various switches re(|uire(l for tlic control ami iijHTatioii of the lighting and

power fetnlers. There ari- a total of ten tri[jlc-j)ole switches for lightAn indicating voltmeter and ann)ere ing, and eighteen for power. meter are also placeil

the .switchlxianl.

iti

.\

voltmeter

is

prcjvidtil

with a tlouhle-throw switch, and so arrangeil as to measure the jxjtential acro.ss the two outside conductcjrs, or l>etween the neutnil con-

ductor and

eitlier of

The ampere meter

the outside conduct(jrs.

is

arningetl with two shunts, one being placeil in each outside leg; the shunts are coimected with a double-pole, double-throw switch, so that the

ampere meter can be coimected

measure the current supplied on

The

Character of Load.

paper

office,

to either

shunt and thus

eac-h sitle of the system.

occupie
is

building

and there are several large presses

in atldition to the

linotype machines, trinuners, .shavers, cutters, saws, etc. also electrically-driven e.\hau.st fans, house

The upper

etc.

to

offices renteil

su[)plit-
2,4(M)

portion of the liuilding to outside

was 55; and the

parties.

total

number

pumps, air-compressors, almost

is

The

usual

There are

total

entirt^lv devoteil

mnnU-r

of motors

of outlets, 1,100, sujiplving

incandescent lamps and 4 arc lamps.

Feeders and

iMains.

und mains, the cut-out

The arrangement

of the various fee»lers

which they supplv,

centers, mains, etc.,

.shown diagranunatically in Fig. 41, which also gives sizes of fee
and motor

circuits,

are.

in scluHlule the

and the data relating

to the

cut-out panels.

Although the current su|)ply was to be taken from an outside .source, yet, inasmuch as there was a pn)bal)ility of a j)l;int l)eing instidled in the building itself at

of feetlers to

the

combined

lL'0-volt tlie

and mains was

some

future time, the three-wiresv.stem

designetl. with a

neutnd conductor

capa<'ity of the two outside conductors,

two-wire generators could

b«-

utili/ed

txjual

.so

that

without any change

in

feeder^.

Tlie plan of the l«isemcnt, Fig. 42, shows the branch wiring for the outlets in the Iwi.sement, and the hn-ation of the main switchlnianl. It al.st) .shows the trunk cables for the intir-

r>a.scmcnt.

«

ircuit

cotmection

.sy.stem

.vning

to

provide the

00

nec«'.s.sar}'

wires for lelephone.s.

FCEDCRS

X ALL CONDUCTORS IN ONt CONDUIT. KX SEPARATE CONDUIT FOR EACH CONDUCTOR THIS FEEOEIR IS TO BE DIVIDED INTO FOUR (-*) ~ CONDUCTORS OF»t 2000000 C-M. EACH. - EACH CONDUCTOR IS TO BE INSTALLED IN A SEP* - ABATE 3" (Inside oiam) conduit LS^LIGHTING SUPPLY " P-S.= POWER XKXX SEPARATE s'tTMSIDE DIAK^CONDUiT FOR EACH M X X

CONDUCTOR

••

in

<

KLECTRIC WIUIXG c^/~i-
rt<^

I

u

1

i

^ -a-'

P SWITCH BOA F^C

i

i7

* nn -Q

-6"

57

ELECTRIC WIRING

58

tickers,

messenger

the rooms throughout the building,

calls, etc., in all

as will be described later.

To

avoid confusion, the feeders were not shown on the basement

in detail in the specification, and installed plan, but were described The in accordance with directions issued at the time of installation.

supply enters the building at the front, and a service switch and cut-out are placed on the front wall. From this point, a

electric current

two-wire feeder for power and a three-wire feeder for lighting, are nm to the main switchboard located near the center of the basement.

Owing

to the size of the conduits required for these supply feeders, as

well as the

main feeders extending

to the

upper

floors of the building,

the said conduits are run exposed on substantial hangers suspended

from the basement through the between the

ceiling.

The

First Floor.

first floor. first

rear portion of the building from the basement Fig. 43, and including the mezzanine floor,

and second

floors, at the rear portion of the

building

a press room for several large and heavy, modern only, newspaper presses. The motors and controllers for these presses are A separate feeder for each of these press located on the first floor. is

motors

utilized as

is

troller in

run directly from the main switchboard to the motor conEmpty conduits were provided, extending from

each case.

the controllers to the motor in each case, intended for the various control wires installed by the contractor for the press equipments. One-half of the front portion of the first floor is utilized as a news-

paper office; the remaining half, as a bank. Second Floor. The rear portion of the second

floor. Fig. 44, is

occupied as a composing and linotype room, and is illuminated chiefly by means of drop-cords from outlets located over the linotype machines

and over the compositors'

cases.

Separate ^-horse-power motors

are provided for each linotype machine, the circuits for the run underneath the floor.

Upper Floors.

A

typical plan (Fig. 45)

is

shown

same being

of the upper

respects with the exception of certain not material for the purpose of illuswhich are in changes partitions, floors, as they are similar in

all

tration or for practical example. intelligible from the plan to require

The

circuit

work

is

sufficiently

no further explanation. Interconnection System. Fig. 46 is a diagram of the interconnection system, showing the main interconnection box located in the

68

ELF.CTRIC WIHIN'G

T:^:

C II

„

I

c_j^

j_

NO POINT X ,

L'^'

?i%--^

^-.^V*:

r

59

SCHEDULE. «" CIRCUITS

d z

^

JL-s:

p

._

i^.i..

€

^n-ai-i

fe-^^-^

mJ v%

tr~Tj

^

ELECTRIC

WTRIN'C;

61

r-^uLC

^

r^^r I

^..

'

•

z^^

^ ^

-

Q-.-.-.-.-.j

<

r*

r

—

oFORCurra 1

r-T"

"I 4

*--=•'

?v0'

r OCR

J«;-n

c.-:

A r

mi

-;-i

?-ir^^-

i^l?^v

'"I

Is

.SHI I'-:: ,;

>

rt.-.-.-.-.-.-ri

In

^ V

:-^' I

J 1

Tyj)lral IMiiii of ll»<

11^'.

4.1.

Wlrlnu of

nil

fpiMTFIoorH. Showing cinuli

Scfouil ucn SliuUiir to oiiK Aiiiithcr In

•

(>••'

\s I';..,..

.
..i

t.

t'liliiiiMtruutt LHiiiillMuf I'uriliUmit.

71

mly

All th<< FliHini

nbore

lii(°uiii|>.ira(tv<
—

FIXTURES.—

ELK(n^i{i(: wiRiN'r;

03

lia.sfimiit; .idjuiiiiii;^ tliis inain Imjx is liicatttl tin- ti-riiiiiial Ihjx of llje

A

liwal tflt'jdioiif (-niii|)aiiy. ft»r tilt'

tickt-r systcin,

insiiIatiDii, aii
was

it

as

.si'j>arato sysU'iii

tlii-se

tlioii^lit

of

fit-dc-rs is

pmviiUil

coiKluctDrs nijuire .vjiiiewluit liravier iiiadvisalile to plare them in the same

coiuluits with the telephone wires,

owing to tlie higher potential of intcreonnection cahle nnis to each fl«K)r, separate for telephone anil messenger call pui-jx)ses; and a central Ih)X i.s place
A

ticker circuits.

to several i)<)ints

svmmetricallv

nm

flo<jrs.

From

to the various ofHces ret|uiring

Small pipes are provitled to ser\e as raceavoid cutting partitions. In this

telej)hone or other service.

ways from

on the various

locatetl

these sui)sidiar}' l)oxes, wires can he

ofiice to ofKce, so as to

way, wires can he c|uickly

office in the building withwhatever; and, as provision is way made for a special wooden moukling near the ceiling to accommodate these wires, they can Ix* run around the room without disfiguring the

out

damaging

All the

walls.

proviiletl

for

any

the Iniilding in any

main cables and subsidiary- wires are connected with numbered serially; and a schedule is

special interconnection blocks y)r(tvideil

in

the

main interconnection box

in

the basement, which

enables anv wire originating thereat, to be readilv and convenientlv traced throughout the Iniikling.

All the

main cables and

subsidiarj*

cables are run in iron conduits.

OUTLET=BOXF:S, CUT-OUT PANELS, AND

OTHER ACCESSORIES Outlct-Uoxcs.

lU'fore the intr(xluction of iron conduits, outlet-

unnecess;int', and with a few extrptions were not usiil, the conduits l>eing brought to the outlet and cut olT after the walls and ceilings were plastered. With the intnKluction of iron con-

were considercnl

l)oxes

duits, however, the necessity for outlet-boxes

of the Fire I'nderwri'ers were

was

realizetl;

and the

so as to re<|uin' their use. The Riiltn of the Xatlifiial KUriric CrnU- lutw rt'«|uin' outlet-lx)Xes to Im- ust-d with rigid irmi and flexible steel conduits, and with annontl llulc.s

cables. All

A

of

the p<jrtion interior roiuluitH

nuHlilit>tl

rule reijuiring their use is as follows: iiniion' <>(|uip|M>ii nt every

nml

with !in iipprnvi'M oullot-l)ox nr pinlf. "Oiitlft-pliitcN iiiUHt not l>o uw(l \vlicn>

iijllot

I1UXC8.

73

it

in |)ritcli(-»l>lo

to

itiHtall uiitlet-

ELECTRIC WIRING

64

"In buildings already constructed, where the conditions are such that neither outlet-box nor plate can be installed, these appUancesmay be omitted by special permission of the inspection department having jurisdiction, pro viding the conduit ends are bushed and secured."

shows a t}^ical form of outlet-box for bracket or ceiling the universal ti/pe. \^Tien it is desired to make an opening of outlets Fig. 47

for the conduits, a blow from

of

a

hammer

weakened portion the wall of the outlet-box, as may be re-

will

remove any

of the

This form of outlet-box

quired.

is

fre-

quently referred to as the knock-out type. Other forms of outlet-boxes are made with

WO OPT 47. Universal and Knocl^-Out Type of Outlet Box.

Pig.

the openings cast in the box at

quired

points,

stronger

and

sal tj'pe.

class

this

better

re-

being

usually the univer-

made than

The advantages

the

of the universal

box will serv^e for any ordinary type of outlet-box are that one form of conditions, the openings being made according to the number of conduits and the directions in which they enter the box. form of outlet-box used out of doors, Fig. 48 shows a waterproof or in other places where the conditions require the use of a watertight

and waterproof

It will

be seen

outlet-box.

in this case, that the

box

is

threaded for the con-

T Fig. 48. VVater-Tight Outlet Box. Courtesy of E. Krantz Manufacturing Co., Brooklyn, N. 1

duits,

for

and that the cover

is

.

screwed on tightly and a flange provided

a rubber gasket.

74

•'IT/A.^DONCOUUMNA .

N'DCI XKna

:...•

OOO- IT" 3T-

R^.^

AHOtTTBCXJDC-

WMMUCTOM

-)_4-4-j4''-1'M-'M''t- i^^'*" FIRST-FLOOH PLAN OF HOUSK FOR

tllAS. A. UUUULA.S. tsy..

I'rlni-llnl K""ln'i i;i MnrtllllK K<">lll." I.O' Tliriiwii I >jH'ri. I'rr>vlili'

.11

'

•

(It)

I

Ihr

m

'"

i'li-I

:.f

'i-

I

i;

.

li

;r-

.

r

1*;\'!

'

W AMI INu

^r:l^•^

I

Iv'v.-

I

U.N. t!

LI,

L.

ELFXTUIC WUilNf; Figs. 49

and 50

sh(i\v water-tij;ht llt^»r lx)xes

Ik)X shall l>e \vater-tij,'ht, titrht

outlet

which the extension tl(M)r

In this ejise

stem

et)ver throujjh

in

flat,

form of

the conduit to the desk or table.

not re(|uired, the stem cover blank cover be use
outlet cDiuiection

removed ami a

A

rases for floor coiuieetions. threadeil, as well as the

is

made

is

is

it

in all

l)e use«l

also, the coiuluit ojR'niiif^

the

which are for outlets

not reijnire that the HiH*r outletstron^'ly reetmiinentUil that a water-

N\ hile the nile.s
the Hikjf.

IiKiiteti in

65

is

(jutlet-l)ox useil

on the market,

Klg.

In;

for flexible steel cables an«l steel ar-

mored cable, has already l>een shown (see Fi^. o). There is hardly any limit to the numlx'r and variety outlet-lK>xes

hen

^^

may

ada|)te«l

f<jr

onlinary and for

makes of

of

sjH'cial

con-

FlK. 50.

4».

Types of Floor Outlet- Boxes.

ditions; l)ut the t^-pes illustrate
and

typical forms.

The

lUishiuKS.

Rules of the Xatitmal Electric Cixlc re«juire that

conduits entering jimction-lM)xes, outlet-lK)xes, or cut-out cabinets., fitttil to .shall be j)n»tect the wire provide«l with apj)ruvcd hu.shing.f,

from abnisittn. Fig. ol is

shows a

This bushing

screwjtl on the v\u\ of the conduit after the latter has Ui-n intro-

ducnl

into the outlct-l)ox. cut-out cabinet, etc., tluTeby

insulated orilice to

and

ciiud\iits, lo<

form of cuuduit bushing.

ty|)ical

k-mit

(

Fig. 52)

ihr (i)iiduit l(Mk-niil

to

iiiid

is

jirolcc

t

liic

win- at

|>nvcii( .ibnision, is .scn-wj-tl

placetl

in

llic

(Ih-

point where slu)rt

grounds, on the threadtxl end of

forming an it

leaves the

cin-uits, etc.

tin-

outlet-lMix or cut-out cabinet,

bu.shing clamp the conduit >ccuiily

7a

in

A

conduit U-fore

and

jxisition.

this

Fig.

ELECTRIC WIRING

66

53 shows a terminal bushing for panel-boxes used for

flexible steei

conduit or armored cable.

The

Rides of the National Electric Code require that the metal

of conduits shall be permanently

and

effectually

grounded, so as

to

insure a positive connection for

grounds or leaking currents, and order to provide a path of in

least

to Pig.

51.

resistance

the

prevent

current from

Conduit Bushing.

finding

a

path

through any source which might cause a fire. At outlet-boxes, the conduits and gaspipes must be fastened in such a manner as to insure good

electrical

connection; and

at centers of distribution,

the conduits should be joined by suitable bond wires, preferably of copper, the said bond wires

Fig.

52.

being connected to the metal structure of the building, or, in case of a building not having an iron or steel structure, being grounded in a

Lock-Nut.

permanent manner Fuse-Boxes, Cut-Out Panels, necessity

was apparent

to

water or gas piping.

From

the ver}' outset, the

of having a protective device in circuit with

the conductor to protect this purpose, a fusible

metal

etc.

it

from overload, short

circuits, etc.

For

having a low

melting point was

em-

The form of ployed. this fuse has varied greatly. Fig.

54 shows

a characteristic form of

what

is

known

Fig. 53. Panel-Box Terminal Bushing. Courtesy of Sprague Electric Co., New York, iV. J.

as

the link fuse with copper terminals, on which are stamped the capacity of the fuse.

The form although

it

is

of fuse used probably to a greater extent than any other, now being superseded by other more modem forms.

76

ELECnaC known

Is tliat

cut-out bliK-k

as

Ch

t\\v luli.son fiij
usi-il witli tlu'

Within the

WIUIN'G

last

I'Mison fuse

Fi^.

sliuwn

is

new form

four or five vears, a

A

'>'>.

in Fij^.

of fuse,

the cnclustd juse, has U't-n intrinhicetl anil used to a

A

fu.se

of this tyj)e

view of this

tional

fu.se-strijjs,

Mown.

and

the

This form of fuse

is

CourtttyufiitnfralKUctricCo., Hchtntctady, .V. }'.

jjorous tilling

made with can he

oS

jcrives

a

sec--

.snrrouiKling the

when

for indicating

the

fuse has

various kinds of terminals:

use
aiiiiMifs; tioii

whether

with s|)ring clips

fusc-hlocks usetl

hut it

small

in

a dchatahle

(|ues-

desiralile to use

an en-

is

it

is

closed fuse for heavier currents.

shows

is

Fig.

'"^

^SF^^

Flg.5«. Porcelain Cut-Out Block.

there

".7.

in sizes, and with a jKJst screw contact low oniinarA' For sizes. jH)tentials larger desirahlc tor currents up to '''''^ ^^''^^' I ^ft^ftl '

mm

^4 (^^^F^P* e

in Fij;.

tlie

ileviee

it

.,^4^^

shown

showing

fu.se,

al.so

is

known as

consitiemltle

Fig. 55. EUlHOn Fuse-Plug, Courttsy oftlenfralEUftricVo. .Sehtntetadi). S. Y.

Mg. M. Copper-TlppeU Fuse Lluk.

e.xteiit.

|>or(fhiin

'>().

with

cut-out ho.r

a

with knoh and tuU' wiring.

no cfninection compartment

Fig.

F^li.s»)n

It will l>e .seen

in this fuse-l>ox,

'»'.>

j)lug

that

as the circuits

enter diR-ctly opj)osite the terminals with which they connect. for enclo-sinl fu.ses. and Fig. ()() .shows a cut-nut panel adaptinl installetl

inet

in

a cal)-

having a


nection t()m|)artineiit. As will l>r Men frr)m the
yJ

®

^

KuiioMHl

Klg. 57.

iir

is

on the 11*;. ^-

four .sides by

which

is .securetl

Im-

woimI hned with sln'et

fpf

1,11'

.slate,

in the

corners

l>y

imn,

aIlgle-iI•^>n^. i>r

it

sliows u door and trim fur a caliiinl nf this

77

may ty|M-.

The In-

outer

of in>n.

It will

Ih»x

may

Fig.

(»!

U- Mfii that

ELECTRIC WIRING

68

the door opens only on the center panel, and that the trim covers and conceals the connection compartment. The inner side of the door

should be lined with

and panel.

and the inner

slate,

side of the trim should be

Fig. 62 shows a sectional view of the cabinet

lined with sheet iron.

In this type of cabinet, the conduits

may

enter at

any

the

wires being run to the proper con-

point,

nectors in the connection

compartment. Figs. 63 and 64

illus-

a

type of panelboard and cabinet havtrate

ing a push-button switch connected with each

branch

circuit

arranged that

and so the cut-

out panel itself may be enclosed bv locked doors,

and access to the switches

may be obtained through

Fig. 59. Porcelaiu Cut-Outs in Wooden Box. Courtesy of II. T. Paisle Co., Philadelphia, Pa.

two separate doors provided with latches only.

This type of panel was arranged and designed by the author of

this

instruction paper.

OVERHEAD LINEWORK The advantages of overhead linework as compared with underground linework are that it is much less expensive; it is more readily and more quickly installed and it can be more readily inspected and ;

repaired. Its principal

disadvantages are that

underground linework;

it

is

more

it

is

not so permanent as

easily deranged;

and

it

is

more

unsightly.

For large

cities,

and

in congested

should not be used.

districts,

overhead

linework

However, the question of first cost, the question of permanence, and the municipal regulations, are usually the factors which determine whether o^'erhead or underground linework shall be used.

78

ELECTRIC Tlu' principal factors to \h:

hriefly

m

mnixG

\)v foiisi
Placing

ot I'olcs.

1(K) to 12') feet

As a

apart, which

^jt'neral rule, the jxilcs is

«-(|uivaleiit

to

'I'A

to

I'luler certain conilitions, these spaciiij^s given will

hut

if

linework will

oiitliiutl.

should 12

have

l>c

set fnjin

)M)les |>er

mile.

to Ije niolifieil;

the |)oles are spacetl too far apart, there is danger of Uhj great jinil on the eross-arnis, pins, and

a strain on the |mi1cs themselves, '

iL "^^^ "^ «-*

ELECTRIC WIRING

70 Poles.

Poles should be of selected quality of chestnut or cedar, free from cracks, knots, or other flaws.

and should be sound and

Experience has proven that chestnut and cedar poles are the most durable and best fitted for linework. If neither chestnut nor cedar even other poles can be obtained, northern pine may be used, and in localities where these poles cannot be obtained; but it is found that the other woods do not last so long as those mentionedj

timber

Pig. 63.

and some to rot

Cnt-Ont Pane! with Pnsb-Bntton Switches.

Cover Removed.

woods are not only less strong initially, but are that is, just quicker at the "wind and water line"

of the other

much

—

apt above and below the surface of the ground. The proper height of pole to be used depends upon conditions. In countn," and suburban districts, a pole of 25 to 30 feet is usually of sufficient height, unless there are

more than two or

three cross-arms

In more densely populated districts and in cities where a required. number of cross-arms are required, the poles may have to be great

80

KLECTRIC WIllING 40

to

00

greater

fet't,

tlu-

or even

|M)»il>ility

Ioii<:er.

of

Of

course,

its lireakiiij;;

or

tlie

71

loiij^er

lH-ii
the

|>ole,

and as the

the

lenfi;:th

increases, the diameter of the butt end of jxile sliould also increase.

Tiil.lcXI

-^ives

the averajje diameters re<|uire«l for various heif^hts of

the poles should 1m- placeil in thegntund. Thes* numlier of standanl s|>ecili(ales,

and

tlie «U'l)th

TABLI-. XI Pole Data

ELECTRIC WIRING

72

Before any poles are erected, they should be closely inspected for flaws and for crookedness or too great departure from a straight line.

Where appearance

is

of considerable importance, octagonal poles

may be used, although these cost considerably more than round poles. Gains or notches for the cross-arms should be cut in the poles before be cut square with the axis of the pole, they are erected, and should and so that the cross-arms will fit snugly and tightly within the space thus provided. These gains should be not less than 4| inches wide,

m*i*rM!^'

Fig.

64.

Cul-Out Panel with Push-Button Switcties.

With Cover.

less than ^ inch deep. Gains should not be placed closer than 24 inches between centers, and the top gains should be at least 9 inches

nor

from the apex of the

pole.

Pole Guying. Where poles are subject to peculiar strains due to unusual stress of the wires, such as at corners, etc., guys should be

employed to counteract the strain and to prevent the pole from being bent and finally broken, or from being pulled from its proper ppsition.

82

EILRCTklC BliLL WIRING. Ill

wiriiit^

fur flec-tric

Itells

to

In-

ojxrnti'd

liy

Imtteiies, the

ilanger of causing tires from short circuits or poor contacts does not exist as in tbe case of wiring for light and power, Ix'cause the current strengtli is so small. Neither is the bell-titter reB[K)n6ible

On this account, Ixdl inspectors or lire underwriters. too often in a careless and done fitting slovenly manner, causthe to results and to require unsatisfactory ing give a|i[»aratU3

to

city

is

frtMjUeiit rej»airs, so that the e.\{)ense

far

more than

offset

and inconvenience

in the

end

any time saved by doing an inferior grade of

Hence, at the outset it is well to state that as much care in the matter of joints and insulation of bell

work.

should be taken

wiring as

in

inexjtensive <

>n

wiring for light or power.

properly installed, the electric bell forms a reliable and yet

If

means

of signaling, and

is

superior to any other.

far

account practically every new building

this

titted

is

through-

nut with electric bells. In

addition to the necessity of tliorouirhness

ahvatly men-

tioned, care should be taken to use only reliable ap])aratus must be installed in accordance with the fundamental

which

j)rinciples

on which

its

satisfactory operation ilejuMids.

\MRi:.

The common Is, 20,

and 22.

sizes of

In general,

wire

use for bell

wor^

are

Xos.

however. No, 20 will be ound

satis-

in

factory as it is usually sutliciently large, while in miny cases No. is not mechanical standpoint. strong enough from

22

.-i

It is

impcrtant that the wires should be well insulateu to _r

«.m^m%m^^w. ^^w. iiw.

vent accidental contacts with

<

i.m.m.«.m.

jire

;

Kirst of staples or other wires. this |)revents the coj)|ht from It also facilJM'ing aefini U|M>n by 'he sulphur in the insulation. ilate.4 Hol I. The iuuer of insulutiou should bo of Ting. coating

all

the wire slinuld

!»«<

tlu<

tinne<|, as

H.M

ELECTRIC BELL WIRING

74

India rubber, surrounded by several longitudinal strands of cotton, outside of which are wound several strands of colored cotton laid

This

on spirally.

is

polished by friction. is

shown in Fig. 1. "When ordering

next immersed in melted paraffin

A short wire,

wax and

length of approved electric bell wire

it is

well to have

it

furnished in several

different colors as this greatly facilitates both the original installation and later repairs, because in this way one line may be dis-

Moreover, a tinguished from another, taps from main lines, etc. it is to wire been found, possible identify it at any having faulty desired section of its length.

METHODS OF WIRING. In running wires, the shortest and most direct route should, of course, be taken between the battery, bells, and bell pushes.

There are two cases to be considered. The better method is that in which the wires are run before the building is completed, and the wiring should be done as soon as the roof is on and the walls In this case the wires are usually run in zinc tubes

are up.

secured to the walls with nails.

The tubes should be from § inch to

^

^ inch

in diameter, preferably It is better to place

the latter.

the wires and tubes simultane-

^

1 Fig.

2.

ously, but the tubes may be put in place first and the wires drawn

in afterward, although this latter that the insulation is liable to become plan has the objection abraded when the wires are drawn in. In joining up two lengths of tube, the end of one piece should be opened up with the pliers

so that

it

may

receive the end of the other tube,

which should

also

be opened up, but to a less extent, to prevent wear upon the tubes are sometimes substiinsulation. Specially prepared paper tuted for the zinc. If the building is completed before the wiring is done, the concealed method described above cannot be used, and it is necessary to run the wires along the walls supported by staples, where

Fig. 2 shows ordinary doublethey will be least conspicuous. an 3 shows insulating saddle staple which pointed tacks, Fig.

84

F.LECriilC liKLL

is

to

\)e

Two

recoiniueiidftl.

the

same

of

short

if it

staple

circuits.

W IKING

iii

wires ehould nevtT he secured under

ean jKissihly la* avoided, owing to the danger "With ii littUi

usually po.ssihle to conl)i>hind the picture mouldini', al(»n
care

it is

ceal tile

wiring

door

and

iK'side the

it is

iinpossihh'

ornamental tinish It

is

to conceal to

casing

of the room,

1

hut whi-rc

j)Osts

a light

it,

k

match the

may

ho used.

sometimes advisahle

Fig.

3.

use

to

in the same outer covering. some cases it is well to run the wires under the iKtors, laving them in notches in the tops of the joists or in holfs hored

twin wires or two insulated win-s run In

ahout two inclu'S helow the

toj)3

of the joists.

JOtNTS. AVlien (•If.iii

making

a joint,

cari'

should he taken to have a firm,

connection, lioth mechanically and electrically, and this must

always he soldered to j)reveMt corrosion. The insulation should off the ends (tf llie wires to he joined, for a distance of Ih* strij»ped ahout 2 inches, and the wires made hright hy scraping oi sandpa-

^^zz^z^^y

E

Vv'.

nering. iifl

They should

shown Me.xt

tlu-n Im-

1.

twisted

tiirlitly

and evenly

toir^tlier

in Fi*'. 4.

comes the

ojieration of soldcriiiR, wliieh

is

ahsolutely

necessary if a jK-rmanent joint froni an »'leetrical stand|H)int is to Iri ohtained. A jdint made without st)liler may he electrically soun
tirst,

hut

its

resistance rajiiilly iiiereas<'s, din< to deteri-

onition of the joint. As has already het-n stated, the wires should Immad(4 hright and clean hefore they are twisted together.

Soldering (luids HJiould never he used, he<-ause of the wire.

The

hest

The soldering should always with a ljIowpijM<

oi

Im'

tlH'V

cause corrosiiMi

or com|M»site candle. done with a eiip|K'r hit rather than

llux to tise is resin

wirenuin's torch.

H&

ELECTRIC BELL WIRING

76

A convenient

form of soldering tool consists of a small copper a semicircular notch near the end. This bit should, of having It is then heated over a course, be well tinned. spirit lamp, or •

bit

wireman's torch, and the notch filled with soft solder. Lay the which has previously been treated with the flux, in this

joint,

notch and turn

it

so that the solder runs completely

around among

the spirals of the joint. The loose solder should be shaken off or removed with a bit of rag. When the joint is set, it should be insulated with rubber tape, so that it will be protected as perfectly as the other portions. It is often possible to save a considerable length of wire a amount of labor by return, which, if

ground

using

and

properly

arranged, will give very satisfactory results, although a complete metallic circuit is always to be preferred. Where water or gas

mains are

good ground may be obby connecting to them, being sure to have a good connection. This may be seavailable, a

tained

cured by scraping a portion of the pipe perfectly bright and clean and then winding this

with bare wire; the whole is then well An end should be left to which

soldered.

/'--^ J

V

—

I

r-h

~

the wire

from the

soldered.

If such

bell circuit is twisted

mains are not

/|-|

1/

-nny^nr^

a

and

available,

good ground can be obtained by connecting

the wire from the bell circuit, as described In the absence of above, to a pump pipe.

water and gas mains, and of a pump pipe, may be obtained by burying beneath

a ground

Fig. 5.

permanent moisture

level a sheet of copper

or lead, having at least five square feet of siirface, to

which the

The ground

plate should be covered with coke nearly to the surface; the hole should then be filled in with ordinary soil well rammed.

return wire

is

connected.

OUTFIT.

The

three essential parts of the electric bell outfit are the bell

which furnishes a means of opening and closing the circuit piish, at will, the battery, which furnishes the current for operating the

86

ELECTIilC BELL WIHING ami the

l>ell,

bell

77

Before discussing the combiimtion of

itself.

these pieces of ap|«iratU3 in thu complete circuit, let us take the individual parts in order.

A

bell

illustration this

is

push

P

presided

of the sprincr

is

is

S

shown diafrrannnatically button; when

in

Fi{^.

ij.

up

In this

the j)ush

uj)on

it

brincrs

in contact

the point

with the

nietul

thus closintr the circuit with wiiich strip K, it is connected in series. Normally the as shown, and the springs are separated circuit

is

accordingly open.

Bell pushes are

made

in various de-

Fig. 6.

signs and styles, from the simple wooden Ttush shown in Fig. (> to very elaborate and expensive articles. of neat apj>earance and modFig. 7 shows four cast bronze pushes enite j)rife. Batteries.

Klectric bells are nearly always operated on the and hence the battery used is generally of the

circuit plan, ojK-n

Fig.

7.

circuit tyjH', such as the I^'danche cell, which in use
op<Mi

of its by jMToxid** of munganese, which gives up part the hydrogen set free and fornuiig water. with oxygen, combining preventtnl

H7

ELECTRIC BELL WIRING

78

Dry Batteries

are also frequently used for bell work, their being cleanliness, as they cannot spill. Dry

principal advantage cells are really a modification of the Leclanche type, as they use zinc and carbon plates and sal-ammoniac as the exciting agent. The cell, which is one of the principal types of dry cell,

Burnley

has an electrolyte composed of sal-ammoniac, chloride of zinc, This compound when mixed is a semiflour, and water.

plaster,

liquid

mass which quickly

The depolarizing agent used in the Leclanche

is

stiffens after

being poured into the cup.

peroxide of manganese, the

cell, this

same

as is

being packed around the carbon

The top of the cell is sealed with bitumen or some similar substance.

cylinder.

For very heavy work the Edison Lalande and the Fuller types of cell are -

best suited, while for closed circuit

the gravity cell Bell. if

is

most

It is a

work

satisfactory. fact that

well-known

a current of electricity flows through wound on an iron core,

a coil of wire

the core becomes matrnetized and

is

ca-

subpable of attracting any magnetic The operation of the stances to itself. electric bell, like that of so

many

other

pieces of electrical apparatus, depends this fact. diagrammatic repre-

A

upon

sentation of an electric bell Fig.

8.

composed wire.

of soft-iron

The armature is

H at

is

shown

in

M

is an which electromagnet cores on which are wound coils of insulated mounted upon a spring K, and carries a ham-

Fig. 8, in

end for striking the gong. On the back of the armature back stop T. The is a spring which makes contact at D with the is closed circuit action of the bell is as follows: "When the through the coils of the around terminal the bell a current flows from 1,

mer

its

K

and contact point D, through the magnet, through the spring back stop T, to terminal 2. In flowing around the electromagnet the current magnetizes its core, which consequently attracts the armaWhile in to strike the gong. ture. This causes the hammer at D is broken, the current ceases to flow tliis the contact position

H

88

ELECTKIC iJKLL WIKIMI the electroiiia^iu't ami the cort'S constHjuently lose their Tht* armature is then carrie
arouii«l

attractive force.

position hv

tlie

retH^atftl.

The

8j)rini^

K, niakinj^ contact at I), and the process is will thus vihrate and the hell continue to

hammer

is closed. ring as long as the circuit The tvp«' of hell descrihed ahove

Such

used.

hells are

made

in a

il

fho one most

commonly

great variety of shajR-s and styles,

It is the prices varying accordingly. imj»ortant that platinum contact l»e furnished at the point I), Fig. S, to prevent cortips

The

rosioii.

hox

hell

shown tyjK^ u-.

is

hells

on the market today are of two classes, the iron A hell of the wocnlen hox tyjR' is Indl.

and the wooden hox

ill

I'ii'.

shown

'.),

in

and a hiidier Kig. 10.


of the iron frame skeleton

without

should never U'

I'ells

cttvers

use*!,

du~t will sfttlo on the contacts and interfere with their action."

CIRCUITS.

The

possihli"

ciriMiit4 !iir

.m,

coiiiliinatiiUis of tin-

varied that

it

would

Ik'

various parts into complete to descriU? iheu* iinpossihh'

ELECTRIC BELL WIRING

80

almost every one is to a certain extent a special circuits the problem. It is, however, possible to give typical of which can be applied successfully to any underlying principles

all; in

fact,

particular case.

in which P Fig. 11 shows a bell circuit in its simplest form, all connected the B the and C the bell, battery; push, represents at P, and hence no curThe circuit is in series.

normally open

rent flows to exhaust the batteries.

When P

is

pressed,

the circuit,

otherwise complete, is closed and current passes through the bell it

causing

^G

^=^G

to ring, as already ex-

For instance, the push

plained.

might be located beside the front

Fig. 11.

door, the bell in the kitchen and the the location depending on the results desired the in cellar; battery and C may, if and conditions to be met. The wire between

P

with and connection made to ground at necessary, be dispensed

G

and G, as shown by the dotted lines. an arrangement by means of which one Fig. 12 shows

B

P

-^

HI P"

Fig. 13.

Fig. 12.

may may

bell

be controlled by either of the pushes P or P'. This system be extended to any number of pushes similarly connected, method for ringing two bells simultaneously from one push

A

where both bells B and B' will ring from push connected in this manner, should have as nearly as the bell of lower resistance possible the same resistance, otherwise will take so much current that there will not be a sufficient amount is

P.

shown

in Fig. 13,

Bells, if

left for

the other.

capacity

as the

Also, the batteries of current taken

amount

must be

of greater current of course, doubled. This of bells connected in this

is,

system can be extended to any number

them. way, up to the limit of capacity of the battery to ring

90

Figs.

v-s*t**"^

SIMPLE COMBINATION GAS AND ELECTRIC FIXTURE

IN

A DINING ROOM

<

<

-z.

3

•-

^"

u

< -J 00

^•

*

<

a

^-

i

O o ^.

3

•

KLKCl 12 and

13 inay

Ih<

Kl(

tUAA, W

•

HUNG

foiubined bo that two or more hells

ruiit^ from any one of two or more pushes. In ¥\ir. 14 is shown a scheme for ringin«^

from one push

anil

one hattery

may

eitlier Ih'II, li

or

Ih>

li',

means of the two-point switch

l»y

wi

re I'iK.

S.

81

II.

"When the arm (jf the switch is on contact 1, the and when on contact 2 it will riiij^ hell W.

jiush will

riniT Ih'II li,

In that

Fii;.

15

li unci li'

is

may

shown

a

method

of connectini; hells in series so

be runn from J\

If all the

bells so coniiecteU

were of the vihrating type, they would not work satisfactorily, as it would he impossihle to time them so that the vihrations would keep

hence only one

step,

hell

should

of the vihrating type, and the others should have the circuit hreakers shortl)e

the vihratiuii hell servinir as

circuited,

interruj»ter for the

whole

series.

Ohvi-

ouslv this system re<juire3 a hii^her volt-

connection, ami

age

than

cells

must

ring

the

hells

Ik'IIs

may

he connecleil

desired,

parallel 111-

up

of

sullicient

in

(»f

this

For

iiistanee, the

way,

if

voltage of the

hattery.

Oftentimes a

to

Several

satisfactorily.

Id the limii

tlic

ll.M.l'.

< "

^ l"lk'-

Im-II

in

>'••

rung from several dilTen-nt places, an e'evator nuiy ht* rung from any one uf

Iwll is to U-

\)l

ELECTRIC BELL WIRING

S2

several floors, or the bell in the office of a hotel

may

be rung from

any one of several different rooms. In this case it is neoessary to have some device to indicate from which push the bell was rung. The annunciator furnishes this information very well. A threestation annunciator

is

shown

annunciator are shown (••iator,

C

the bell,

li

or instance,

when P'

in

The connections

Fig. 16.

for an

Fig. 17 where tV represents the anunthd battery, and P', P", and P^ the pushes. in

pressed, the current passes through the electromagnet controlling point 1 on the annunciator which causes I

is

I

B

13

pfe i

Fig. 17.

the arrow to be turned and at

attendant has noted

tlie

no

iiiul

tlie

same time the

siu;iial,

arrow

tlie

pressing a lever on

by

position

tlie

tlie

bell rings. is

After

restored to

its

bottom of the annun-

ciator box.

The tion

and

burglar alarm furnishes a very efficient protecan application of the principles already described. Tlie

electric is

circuit, instead

of being completed

by

a

push,

is

completed by

contacts placed on the doors or windows so that the opening of The same device may be used either will cause the bell to ring.

on money-drawers,

safes, etc.

In the case of the electric

fire alarm, the signal may be given the temperature reaches a certain degree, or pushes may be placed in convenient' locations to be operated should be protected by glass so that they The

either automatically

manually.

will not be

when

pushes tampered with,

it

being necessary to break the glass

to give the alarm.

02

LIVING ROOM IN RESIDENCE OF J. R. CRAVATH, CHICAGO. ILL. A good Arrangement for Reading and General Lighting in a Small Hoom.

ELECTRIC LIGHTING HISTORN AM) I)11\HL()I>M1:M Tlu- liistorv of (Icitric

li^'litint;

as a coniincrfial proposition In^gins

the invfiitinii of the (inimiiic dyiiaino, liv Z. J. (irainiiif, in 1n7U, tuiiftluT with thi- iiitrothictioii of thi* Jaltlochkoir caiuilf or

^villl

which was

li^'ht,

aniiouiict'd to

first

formed a feature of

tlie

to this time, the eh-ctric hjjht

rp

one of the arc,

tlie

earliest l)ein<j Sir

and and

trtnles

ptil)nc-

was known

Iluinphrev

arc of any jjreat maj^nitudc. resulted from the use of two

first

tlif

in 1870,

and which

International Exposition at Paris in 1S7S,

It

few investipitors,

to hut

Daw who,

in

was then

IMO, pnHluctd

called the voltaic

wood charcoal pencils as eleca powerful battery of voltaic cells as a source of current.

From IMO to 1S.")9, many j)atents were taken out on arc lamps, most of them oj)erated hy clockwork, hut these were not successful, due chiefly to the lack of a suitahle source of current, since all deThe interest in this form cells for their ])ower. on jH-nded

of

lij,'ht

i)rimary died down about 1S')0, and nothing; further was attempted

advent of the (iramme dynamo. incandescent lanij) was but a piece of laboratory apparatus to at which time Kdison produced a lamp usinfr a platiinim 1S7S, up in a vacuum, as a source of Iij,'ht, the platinum beinj,' rendered

until the

The

spiral

incandescent by the passage of an electric current through first

successful carbon hlament

form«'d from strips of

bamboo.

was made The names

it.

The

in 1S70, this filament being

of Kdison

and Swan are

intimately coimecfcd with these early experiments. From this time on, the dcvrlopmciit of electric lighting has Ihh-u and tin- consumption of incandescent lamps alone has Verv rapid, d several

When we compare the small millions t-ach year. means of amount of lighting done by i-lectricity tw«'nty-five years ago uiih the enormmis extent of lighting systems and the numerous r
ill

illumination as they an* to-^lay, the growth a|>pli
a *tu«ly of this subject

may

Coj/f right, imto,

Im-

readily appreciat«tl.

While

b^ Amtrican ScAool qf CorruponJtnct.

on

in

many

ELECTRIC LIGHTING is not the cheapest source of power for ilhimination, admirable qualities and convenience of operation make it by far

cases electricity its

the most desirable.

CLASSIFICATION

The

subject of electric lighting

may

be

classified as follows:

The type of lamps used. The methods of distributing power to the lamps. The use made of the light, or its application. Photometry and lamp testing.

1.

2. 3. 4.

The

types of lamps used

may be

subdivided into:

Incandescent lamps: Carbon, metallic filament, Nernst. Special lamps: Exhausted bulb without filament, such as the Cooper-

1.

2.

Hewitt lamp and Moore tube lamp. 3. Arc lamps: Ordinary carbon, flaming

arc.

INCANDESCENT LAMPS The

incandescent

used, and the If

PR

t,

principle of

a current /

R, for a time

PR

t

lamp

is

is

far the

most common type

is

of

lamp

as follows:

operation sent through a conductor whose resistance

the conductor

/,

by

its

is

heated, and

the heat generated

is

=

representing joules or watt-seconds. and conditions are so chosen that the

If the current, material,

substance

may

be heated in

this

way

until

it

gives out light,

becomes

incandescent, and does not deteriorate too rapidly, we have an incandescent lamp. Carbon was the first successful material to be

chosen for

this

conductor and for ordinary lamps

small tlu-ead or filament.

it is

formed into a

Very recently metallic filament lamps

have been introduced commercially with great success but the carbon incandescent lamp will continue to be used for some time, especially in the low candle-power units operated at commercial voltages. Car-

bon

is

a successful material for two reasons:

L The

material must be capable of standing a very high temC, or even higher.

perature, 1,280° to 1,330° 2.

It

must be a conductor

of electricity with a fairly high re-

sistance.

as

Platinum was used in an early stage of the development, but, shall see, its temperature cannot be maintained at a value high

we

enough

to

make

the

lamp as

efficient as

06

when

carbon, or a metal

FM^' Tinr T.KJHTIXG

liii\

all

in;;

a

iiifltiii rel="nofollow">; |)«>iiit liij^lirr

attempts

faih'tl until

than that

rrcently,

and the few

lainj>.s

The

.successful will Im- treal»'
«if

{tiatiiiuiii,

sulistitutr aiiotlifr siihstaiK-e In

t«»

incandescent lamps has, however, forms, and owinj;

to the

is us«-(|.

phuv

Nearly

of <-arlMJH have

which are entirely

c>r

|)artia)ly

nature of the earhon eniployi-il l»ei-n

much improved

()Ver the

very j^reat imj>ortance of this lamp, the nielliiid of niannfactiirc will l>e cuiisidcred.

first

still

A\anufacturc of Carbon Incandescent Lamps. J'n pardlitm vf (illidosc, a chemical compouml rich in carlM^n, is

the rHiiiiuiit.

cotton with zinc chloride in pn»per prepared hy treating ahsorltent to form a mass. It is uniform, <,a'latinc-like customary projjortions to stir this under a partial vacuum in order to remove huhhles of air

which mi^ht he contained

in

it

and destroy

its

uniformity.

This

"

material

is

then forced, "stjuirtetl,

Fit;.

1.

through

now

of Filuniriit.s

Fiirni.s

steel dies into alcohol, the

in I'.so.

Thi'sc threads in^' lu harden the soft, transparent thread>. are then tiioroughly washed to remove all trace of the zinc chloride, dried, cut to the desired lengths, wound on forms, and carbonized by

alcohol >cr\

heating to a high temperature

away from

air.

I

)uring carbonization,

transformed into pure carbon, the volatile matt«T being flriven off by the high temperature to which the Hlaments an- subjectitl. The material becomes hard and stilV, assuming a permanent f»»rm, the cellulo.se

is

shrinking in both length and diam«'tcr— the form being s|M'eially constructed so as to allow for this shrinkage. The forms an- made of

carbon blocks which are placed with j)owden-d l(M»sely

at

fitting

carbon.

The

in

carbon covers, are gradually brought

which tem|H-ratiire the cellulose

allowed to

and

iim>|.

insjM'cted,

|)luinbago crucibles and packed which are covjtimI with

crucibles,

is

ehangeil

.Xficr cooling, the filaments are

and

to a

and then

removeil, lueasund,

the few jlcfcctive ones di.scardinl.

07

white heat,

to carlH)n,

ELECTRIC LIGHTING In the early days, these filaments were made of cardboard or

bamboo, and

A

later, of

thread treated with sulphuric acid.

few of the shapes of filaments now in use are shown in Fig.

1,

the different shapes giving a slightly different distribution of light. As here shown they are designated as follows: A, U-shaped; B, single-curl; C,

anchored; D,

single-curl

double-loop; E,

double-

curl; F, double-curl anchored.

are

After carbonization, the filaments Mounting the Filament. mounted or joined to wires leading into the globe or bulb. These

wires are

made

of platinum

—platinum being the only substance, so

and contracts the same as glass, with at the same time, will not be melted the carbon. Since the bulb must remain

that expands

far as

known,

change

in temperature

and which,

by the heat developed

in

substance expanding at a different rate from the glass air-tight, a cannot be used. Several methods of fastening the filament to the leading in wires have been used, such as forming a socket in the end of the wire, inserting the filament, and then squeezing the socket the use of tiny bolts when cardboard tightly against the carbon; and

filaments were used; but the pasted joint sively.

Finely powdered carbon

is

now used almost

exclu-

mixed with some adhesive com-

is

pound, such as molasses, and this mixture is used as a paste for fastenLater, when current is sent through ing the carbon to the platinum. the joint, the volatile matter

is

driven

off

and only the carbon remains.

This makes a cheap and, at the same time, a very efficient joint. Filaments, prepared and mounted in the manner Flashing. uniform in resistance, but it has been found just described, are fairly much improved and their resistance very be that their quality may a layer of carbon closely regulated by depositing of the filament by fashing. By flashing process filament to

a high temperature

when immersed

on the outside of the

meant heating

is

the

in a

such as gasoline vapor, under partial vacuum.

hydrocarbon gas, Current is passed

through the filament in this process to accomplish the heating. Gas used, rather than a liquid, to prevent too heavy a deposit of the carbon. Coal gas Is not recommended because the carbon, when black appearance. The effects of deposited from this, has a dull

is

flashing are as follows: 1.

The diameter

carbon and hence

its

of die filament

resistance

is

is

increased by the deposited

decreased.

ds

The

process must be

I.KiHTING

FI.Kr'rUK

(liscoiitimiftl

u

lii'ii tlit-

cK-siri'il

iarities in the filament will

having the

resistance

is

reueljed.

Any

little

irrepi-

We eliminated since the smaller sections,

j;reater resistance, will

of the filament anil the carlion

l>ecome hotter than the remain
is

(Jeposited

more

rapitJIy

at these

points.

The

2.

character of the surface

is

changed from a

dull

Mack

which is much c<)mj)arativcly soft nature to a Kright gray coating harder and which increases the life and efficiency of the filament.

and

After flashing, the filament is sealed in the bulb and the air exhausted through the tube .1 in Fig. 2, which shows the Kxhauisi'uKj.

in ditTereiit stages of its

lamp

manufacture.

The

exhaustion

accomplished by means of mechanical air pumps, supis

j)lementcd by Sprenglc or mercury j)umps and chemicals.

Since the degree of exhaustion must be high, the bulb should

be heated during the process so as to drive off any gas which may cling to the glass. When chemicals are used, as

is

now

almost universally the case, the chemical is |)laccd in the tube -1

when heated, serves up much of the remain-

and,

to take

Kxhaustion is necesing gas. sary for several reasons: 1.

2.

3.

DIIToreiit

Fin.

StuKCx

To avoitl oxidization of thi- tilniiipnt. To rcililcc the heat Cdiivcyi'il to tin- jtIoIm-. To prevent wt-iir on tlir filament iliu- to ciirn-nts

III

I'Uiiip Muiiufu<'iur(<.

or ciMics in the

cart.

After exhausting, the tubi- .1 is sealed olT and (lie lamp lommeans of plaster of I'jiri.s. pIcUil for testing by attaching the base by FJL'.

< \

ty|M'

shows some of the forms of completed incandescvnt lamps. oltage anil Canillc-I'owcr.

Incandescent lamps of the earlH)n

candelabra lamps to vary in size finni the miniature l>att«ry and

those of .several humlrcd caiidlc-jiower. though flic lallcr are very The more common vjdues for the canillc-power are seldom used.

»f>

ELECTRIC LIGHTING and

8, 16, 25, 32,

made

use to be

50, the choice of candle-power

depending on the

of the lamp.

The voltage will vary depending on the method of distribution of the power. For what is known as parallel distribution, 110 or 220 volts are generally used. For the higher values of the voltage, long and slender filaments must be used, if the candle-power is to be low; and lamps of less than 16 candle-power for 220-volt circuits are not practical, owing to difficulty in manufacture. For series distribution, a low voltage and higher current is used, hence the filaments may be quite heavy. Battery lamps operate on from 4 to 24 volts, but the vast majority of lamps for general illumination are operated at or about 110 volts.

Fig. 3.

power

Forms

of Completed I^amps.

the efficiency of an incandescent lamp is meant at the lamp terminals per candle-power of light required

By

Efficiency.

the

Several

Thus, if a lamp giving an average horizontal candle-power given. of 16 consumes \ an ampere at 112 volts, the total number of watts

consumed

will

^

be 112

=

X

\

=

The

and the watts per candle-power efficiency of such a lamp is said to be 56,

will

be 56

3.5

watts per candle-power, or simply watts per candle.

economy

The

is

16

3.5.

sometimes used for

Watts

efficiency.

lamp depends on the temperature at which the filament is run. In the ordinary lamp this temperature is between 1,280° and 1,330° C, and the curve in Fig. 4 shows the increase of efficiency of a

efficiency with the increase of temperature.

100

The temperature

attained

TivTRir

!

l)V

a

lilaiii.

amount

of

tioual to

..i

...

jM-iitls

powir

tlu- art'a

on

at wliicli

rati-

tin-

suj)|)li(il.

i.I(;htin(;

lii-at

is

nKHatt-d and the

Tlu- ratt- of ratliation of lu-at

of the filaint-nt,

tin* tltvaticjii in

is

pn)[Mjr-

tinnHratiire,

and

the emissivity of the surface.

Bv

einis-sivity is

meant the nuinlur of heat

units <-mitte(l

from

unit surface per (U'»jree rise in tcm[)
than

tlie

(hill

surface of

enerjjy is lost in licat railialioii

an unhcatcd fihiment, hence

and

tin-

U'ss

cllicicncy of the filament

is

increased.

As soon as incandescence is reached, the illumination increases much more rapidly than the emission of heat, iience the increase in 1400

ELECTRIC IJGHTING neighborhood of 800 hours. To obtain the most economical results, such lamps should always be replaced at the end of their useful life. In Table I are given values of efficiency and life of a 3.5-watt, 110- volt carbon lamp for various voltages impressed on the lamp. These values are plotted in Fig. 5. The curves show that a 3% increase of voltage on the lamp reduces the life by one-half, while an increase of value.

6%

The

causes the useful

effect is

to one-third its

life to fall

normal

even greater when 3.1-watt lamps are used, but

not so great with 4-watt lamps.

From

this

we

see that the regulation

on the system must be very good if high be used, and this regulation will determine the

of the voltage used

efficiency

lamps are

efficiency

of the

to

lamp

to

be

Selection of

installed.

Lamps.

watts per candle-power of voltage

is

the best

Ordinary Carbon Type.

will give satisfaction

only

at

TABLE

I

Effects of Change in Voltage

Standard Vo'.TAQE

the

regulation —practically a constant voltage maintained the

normal voltage of the lamp.

Per Cent, of Normal

Lamps taking 3.1

when

3. 5-

Watt Lamp

LUiUriNG

FTF< lUIC

«j

17C

I«c 151.

14C 13C-

ISO

IK IOC

9C

8c 70-

6c

Curves of Eniclciiry nnd

1-itr.

Lamps rt 1^1

latioii is

I'lMI |>

sjiuuld

I^ife

o( Carlton Filunient Ihiiuph.

of 4 walls per canclle-powiT should \>c installed wlu-n the 22()-volt Tlu-se valiU'S are for llO-volt lamps. poor.

A

have u lower efheiency

FIk.

fi.

I.lfc Ciirvif)

to give a

of Iiican(l<>w«Mit

long

life.

This

is

on

Ij>iii|m<.

account of the fait that, for the same candle-power, the 2'JO-volt lamp must he eoiistruete
pare
short.

tc-mperature its life is consi<|eral»l«' extent ahroad hut iiigh

United Stales. of alMinl

I

It is

it

The is

22()-volt lam|>

is

use
some

not em|)loy«-
ciistonmry to oprrate such lamps at an eflieieney

watts |mt candle-power.

lo:l

ELECTRIC LIGHTING

10

should always be renewed at the end of their useful life, being termed the smashing-point, as it is cheaper to replace

Lamps this point

the

lamp than

mend running reduced

life,

Fig.

to

and

7.

Some recomat the reduced candle-power. means at a at a but that higher voltage, lamps

run

these it is

it

not good practice to do

this.

Horizontal Distribution Curve for Single-Loop

ril..n-.ei.t.

of incandescent lamps. Fig. 6 shows the life curves of a series These curves show that there is an increase in the candle-power of some of the lamps during the first 100 hours, followed by a period during which the value is fairly constant, after which the light given

by the lamp

is

gradually reduced to about

power.

104

80%

of the initial candle-

FT

Distributiun

u\

rrTRir lighting In

lA^hl.

filamriit.s iisi-d in iiuaiMK-scrnt

tribution of section.

lamp

l)cing

from a

lij,'lit

Fij,'.

7

arc .sliown various forins of

lamps, and Figs. 7 and 8 show the dis-

sin|,'N'-l<M)[)

shows the distribution

mountetl

1

Vi}^.

11

filament of cylindrical crossin a horizontal plane, the

«)flij,'lit

in a vertical position,

and

Fig. 8

shows the

dis-

o N (VI

FIr. S.

Vcrllcul DiHlrllmtInn

Purvc

for SIiikIp-Ixhip Fllimirnt.

By chaiipng the shape of the iilament .\ mean of the reatlings taken in forms the iiiftiii horizontal raiidli-jMnnr, and

triljulion in a vertical pljin«'.

the light distrihution till-

horizontal |)lane

varied.

is

this (•andle-pt)Wer rating

gives us

tin-

mean

is

the «)ne generally assume
mean

f(»r tlu*

«)nlinary

of the readings tak«'n in a verti<«l plane vertical candle-power, init this value is of little use.

itnandesceiit lamp.

.\

105

ELECTRIC LIGHTING

12

Mean give an

Spherical CandIe=Power.

entirely

different light

When comparing lamps

distribution,

mean

the

which

horizontal

candle-power does not form a proper basis for such comparison, and the mean spherical or the mean hemispherical candle-power is used instead.

By mean

is meant a mean value of The methods for determining this up under photometry. The mean hemispherical candle-

the light taken in will

be taken

power has tal

spherical candle-power

all

directions.

reference, usually, to the light given out below the horizon-

plane.

The Gem Metallized Filament Lamp.

When

the incandescent

lamp was first well established commercially, the useful life of a unit, when operated at 3.1 watts per candle, was about 200 hours. The improvements in the process of manufacture have been continuous from that time until now, and the useful life of a lamp operated at that efficiency to-day is in the neighborhood of 500 hours. Experiments

in the treatment of the

carbon filament have led

to the intro-

metallized filament lamp. This lamp should not be confused with the metallic filament lamps, to be described later,

duction of the

gem

because the material used

is

carbon, not a metal.

As a

result of

special treatment the carbon filament assumes many of the characteristics of a metallic conductor, hence the term metallized filament.

The word

graphitized has been proposed in place of metallized.

TABLE *

Watts

Data on the

Qem

II

Metallized Filament

Lamp

< " ^ <

i

I

I

<

CO

O Q < 2 O

i

o = < o rt

-a S, flj

Q IS

as

E OS

o bh

bl

u

(/} 1=)

o X

o o K

C3

Z

o

a a

:3

<

tt

J-7.

< c'_

3 -e =c —a E ^

i I--

s s

„•

5

=

cs

:^

it"?

r

-i

r

•"

-r

111 K

1 it

3

<

M

EI.KCTUir T.KillTIW; \Micii a tilaim-iit, as

tn-ali-il in tlie

it

was

«Jiscoveretl that,

if

thi-

onlinary iiiuniKr,

no iinpruveinent uf tn-atccl tihiiuents were

hi^li tfinpcratiiri- in a lani|) tlii-re

hut

13

i.s

is

tlie

run at a iilaincnt,

suhj<-ctetl

to

—

thr extrt-inily hiijh tfnijRTatnrc of tlie eh-etric resistanee furnatr at atmospheric pressure, the 3,IMM) to .S,7(K) (lefj^rees C. physical nature of the carlK)n was chanjjed and the n-suUinj; fihiinent coul«l Ije

—

operatcil at a higher tcinjH'ratiin- in the to

lamp ami

a hi^'hcr efficiency,

ELECTRIC LIGHTING

i4

The for the decrease in candle-power of the incandescent lamp. 2 of 5 watts at an is metallized filament lamp efficiency pei operated candle with a useful

life

of

power with change

The change

about 500 hours.

in voltage is less

in candle-

than in the ordinary lamp on

account of the positive temperature coefficient of the filament. These low candle-powers, owing to the lamps are not manufactured for very of

difficulty

very slender

treating

ments, but they are

made

suming from 40 to 250 watts. gives some useful information

Table in

made

II

connec-

tion with metallized filament lamps.

filaments are

fila-

in sizes con-

in a variety of

The

shapes

and the distribution curves are usually modified in practice by the use of shades

and

The

reflectors.

of the

general appearance

lamp does not

differ

from that of

the ordinary carbon lamp. Fig. 9 shows the metallized typical distribution curves of

filament Fig. 10.

Round Bulb Tantalum Lamp.

lamp

as

it is

Metallic Filament

talum Lamp.

The

installed in practice.

The Tan-

Lamps. first

of the metallic

filament lamps to be introduced to any considerable extent comDr. Bolton of the Siemens mercially was the tantalum lamp.

&

Halske Company metal

tantalum.

discovered the methods of obtaining the pure This metal is rendered ductile and drawn into

first

slender filaments

cent lamps.

tensile strength

point,

for

incandes-

Tantalum has a high and high melting

and tantalum filaments are

operated at temperatures much higher than those used with the

carbon filament lamp. On account of the comparatively low

Fig. 11.

Tantalum Filament Before and After 1,000 Hours' Use.

specific resistance of this material

110-volt lamps must be long and slender, and a special form of support. Figs. 10, 11, and 12 show some interesting views of the tantalum lamp and the fila-

the filaments for this necessitates

ment.

This lamp

is

operated

at

108

the

efficiency

of

2

watts per

ELFXTniC T.UillTINC (aii(llr-|Mt\Vfr,

Hy

hhiiiH'iits

a

witli

trratiiu-iit

sjH'cial

so

lift-

it

(hat of

l
(-iiiii|>aral)l<-

15

tiit*

urditiary Iam|>.

possiMc to iiHTt-asf tin* r«-sistaiicf of the Iw shortt-r and heavier than those used in

is

tliat tht'V iiiav

H

^ J

i

FiB. 12.

AppciiniiK-c of Kiluinent After lIuviiiK IJWMi L's«l.

the

first

this

of

tlie

type of

tain;

is

it

circuits.

lamp,

an
taiitahini

Filanioiit

It

lamps.

mueh more Ki;:s.

!.'{

1\'

^ive

and 14 show

some

eireuits

is

"general data

TAiu.i; III)

111

lai)t;iliirn

(iKNKUM- KI.KITIUC

Sick or IIui.h

RrniTi.Aii

Ui>rM>

of

direct-
on the tantalum

typical distrihution curves for the

units as installed at |)resent.

Data

life

somewhat uncer-

operation on

satisfactory for

and

Klluiiiont.

should he noted that the

lamp on alternatin<;-eurrent

'I'ahles III

Knuiu' Sliowini;

Ur«>ki'ii

Ci

l.nmp i ,

MKTKS.

ELECTRIC LIGHTING

16

T/vBLE IV Data on the Life

No. OF Hours Burned

of a

25 =C. P. Unit

IN TUIC I-KHITING

17

«

to OIK' of

tiiii<jstt

tuiig-sti'ii

and

A

II.

srcoiid iiiftlKxl

foii'sist.s

of the

of

list-

jMi\vtli-rf«l

orpmit- and in otln-r is mixed with the hindinj^ and the hindinjj material is

.somt- hiiuliiij; niatcrial, sonietiim-.s

The

cases metallic.

powderctl

tiiiijjsten

the paste stjuirtetl into fihiiiieiits, then expelled, usually \>y the aid of heat. Another metluxl

iiiatiTJal,

facturt

consist.s of securinj.; tunijsten

in colloiilal

form,

<)f

manu-

s(|uirtinf,'

it

so"

A^c'i

JO

*0'

riK.

iiitii

U.

Curves

Dl-Htriluitioii

lilainents,

^PO"

and

(ln'ii

O*

10'

for Tiuituliim

I.i

N".

nip

A

JO

PO^

/O*

I. -lO

Wuttji:

chan^'iii^ tlicni to the metallic

No

form

2. sii

Ity

Wniin

passinj^

electric current tlinni^'h the filaments.

The

tungsten

laiiip

lias the

highest eflicieiicy of any of the

mercial forms of nu'tallic filament lamps so as to |M'r candh'-|)ower when oju-rated for llO-volt service

put on the market. Im-

a |»ossil)ility.

power

and consiiminj; hut .\ 2.'»-watt

The

lamp

now ijive l((

iH-caiise of the difliculty

i>f

1

a normal

life,

1.2.')

1

comwatts

and lamps

same

first

volta^je ap|M'ars to

were of

hi;;h

manufacturing the slender

required for the low candle-pow<-r lamps.

I

ahout

watts have re«>enlly Im-ch

for this

units intr
in um-,

candle-

lilanient."

ELECTRIC LIGHTING

18

The advantages

of these metals,

tantakim and tungsten, for

incandescent lamps are in the improved efficiency of the lamps and of the light, white or nearly white in both cases. the

good quality

In either case the change in candle-power with change in voltage is The less than the corresponding change in an ordinary carbon lamp. filaments must be made long and fact that the in the lies disadvantage slender,

Fig.

and hence are

15.

fragile, for

Multiple Tiingsten

on commercial voltages.

Lamp.

low candle-power units

Fig.

1

6.

Series

to

be used

Tungsten Lamp.

In some cases tungsten lamps are con-

structed for lower voltages and are used on commercial circuits through the agency of small step-down transformers. Improvements in the

process of manufacture of filaments and of the method of their supcandleport have resulted in the construction of 110-volt lamps for

powers lower than was once thought possible. Figs. 15 and 16 show the appearance of the tungsten lamp, and Figs. 17 and 18 give some

112

rilT'I-KK

tvpic-al a-s it is

TaMfs

(listriliiitioii »iir«»-.s.

nianufaclurfil at

LK.IITINC; and

\'I

pve

daUi on this lamp

)ne very fonsicJeraMe applicatiuri

(

prt'sriit.

\'

10

40'

FIk. 17.

f.

l".

Distrilnition

IncandetK-ent

of

tlie

I'liils

CurveR of 10()-Watt fien. Klecv Tungsten 11-3, r-3, and I)-3 Holophanew.

with

tungsten lamp is to incandescent street lif,'liting on series cirwhich case the himp may l>e maile for a low voltajje across

cuits, in its

terminals and the filament

mav

l)e

made comparativelv •

I

•

short

and

90*

BO'

70'

60'

^'»^•

In.

1'i.mllf riiHor DlMrlluitloii (ilviMi SitIi-x

heavy.

The

lamp. The .lust

Uiiiipiind Kiillal

tungsten lamp

is

wllh 10

Wuvo

r.

p

1{<>11«><

(ion.

KIw.

TiinRrtcii

lor.

also Ixiiig introduced as a low v<>l(age

I'.iitiry

laiMji,

tin-

/

laiuji.

ihe

(

)sram lan>p, the Ziri-«>n-W«»lfram

Osmin lamp, etc.. are all tungsten lamps, the filamenls laiMp, heing prepand l»v sonjc of the gt'tieral methiMls alreatly ilescrilxd or tlu'

nKxIilicalions

<>f

iln-m.

ELECTRIC EIGHTING

20

TABLE V Tungsten Lamps

MULTIPLE Watts

KLEfTHir LKJIITIXG TABLt McltinK Point of

Mir*

1.

VII

Some Metals

21

ELECTRIC LIGHTING

22

ing process forming the filament or glower material of the lamp as represented by the lower white line in Fig. 23. The more recent

glowers are

made hollow

The

instead of solid.

glowers are cut to

and platinum

the desired length

ter-

The attachment

minals attached.

of these terminals to the glowers

an important process facture

of

is

in the

manu-

The

recent

the lamp.

discovery of additional oxides has led to the construction of glowers

which show a considerable gain

in

efficiency over those previously used. The glowers are heated to incan-

descence in open

a vacuum not

air,

being required.

As the glower is a non-conductor cold, some form of heater is

when

necessary to bring

it

up

to a

tem-

perature at which it will conduct. Two forms of heater have been

One

used.

of

them

of a

consists

porcelain tube shown just above the glower, Fig. 23, about which a fine

platinum wire

wire

is

Two

is

wound;

the

in turn coated with a cement.

or

mounted

more

of these tubes

are

directly over the glower, or

glowers, and serve as a reflector as well as a heater. The second

form of heater consists of a slender View of Multiple Glower Westinghouse Nernst Lamp.

Fig. 20.

Sectional

a cement.

This rod

is

rod

of

refractory

material

which a platinum wire

is

about

wound,

the wire again being covered with then formed into a spiral which surrounds the

glower in the vertical glower type, or

is

formed into the

icafer heater,

now

universally employed in the Westinghouse Nernst lamp with horizontal glowers. The wafer heater is bent so that it can be Fig. 24,

mounted with

several sections parallel to the glower or glowers.

116

F.I.KrTlUr I.KiirilNr,

Thf is first

lu'atiiij;

on, and

tunu'(|

become

(levicf

in

con(luct<»rs

i.s

it

c-unnf
order to save the

circuit

when

heater ai.d to prolong the

means

(jnerated hv

life

enerj;_v

of ihr licater.

the laiiip

circuit after the j;hjwt'rs

consuraetl

Sectional Views of Single-iiluwer Wi-stlim'house Nenist

Fig. 21.

is

tlit*

must he cut out of

23

l)V

the

Lamp.

The automatic

cul-out

of an eh'ctroma;;net so arranfjcd that current

flows throujih this ma<,Miet as .soon as the j,'lower l)ecomes a conductor, in the heater circuit

ami contacts are oi)cne(I

l»y

in

<-ontacts

the

this

ma<;nct.

The

heater circuit are

the kept normally closed, usually hy fupic uf gravity.

The increa.se.s

perature tive if

it

tial

and to

conduclivily of the gjoucr with the increase of (ciii-

— the

material has a nega-

hence temperature coedicienlwere used on a constant potencircuit

tlircctly,

lem|)erature until the

rise

.stroyL'«l.

T"

the

woiihl

current

contimic

glower wa.s iU-

prevent

(he

current

11^

llunifT.

ELECTRIC LIGHTING

24

from increasing beyond the desired value, a ballast resistance is series with the glower. As is well known, the resistance of iron wire increases quite rapidly M^ith increase in temperature, and used in

the resistance of a fine pure iron wire so adjusted that the resistance of the

is

combined ballast

circuit of the

glower and the

becomes constant

at the desired

temperature of the glower. The iron wire must be protected from the air to

prevent oxidization and too rapid

temperature

changes,

is

mounted

reason, filled

it

with hydrogen.

been selected

for

this

in a glass

bulb

and,

Hydrogen has

purpose because Westinghouse Nemst Screw it is an inert gas and conducts the heat Fig. 23. Burner with Globe Removed, e u ii x xi ii ^i ^^"^ j.u ^^^ ^^^11^^* to the Walls of the Showing Glower and Tubular Heater. bulb better than other gases which for

tliis

j.

/•

might be used. All of the parts enumerated, namely, glower, heater, cut-out, and ballast, are mounted in a suitable manner; the smaller lamps have but

one glower and are arranged

to

fit

in

an incandescent lamp socket,

while the larger types are constructed at present with four glowers

—

i:

Tlu- injvantatjfs

r.ECTRIC LIGHTING »

ciiiicv; a jjchmI color of iisi-

of rdifitoi

eoiiij)li'te

thus aliowiui; tically all

The

•

series

a

its

li^'lit;

loll-;

life

sizes

i.«f

fur

laiiiHMl

a(la[ttioii

of to

a

tlu-

<,'o(k|

N'«rn>t

25

lamp

distrihiitioii of

with low cost of

an-:

li-;ljt

Ili^'li

tfli-

without the

iiiaiiitciiaiicf;

ami a

units, j)ra(-

classes of illumination.

lamj)

Ixith tlirect-

and

is

constructi'il

for

alternatin;,'-curniit

service anil for 110

and 220

volts,

^^hcn the alternatinjj-currcnt lamp is used on a 110-volt circuit a small transformer,

commonly

called

a

converter coil, Fig. 2o, is utilizi-d to raise the volta<,'e at the lamp ter-

minals to ahout 220

Fig. J5.

CoiivertCT Coil.

volts.

Data on the Xernst lamp in its present form are piven in Table ^I1I, and Fif;s. 2() and 27 show the form of dislrihution curves.

TABLn Mil General Data on the Nernst Laui-

K .ITINO l.s Wattb

lamp

ELECTRIC LIGHTING

26

given, approximately 3.1, 2.5, 2, L25, and L2 watts per candle respecThe figure of L2 watts per candle for the Nernst lamp is tively.

based upon the mean hemispherical candle-power and it should not be compared directly with the other efficiencies. The color of the light in all of the above cases is suitable for the majority of classes of illumination, the light from the higher efficiency units being somewhat whiter than that from the carbon lamp. All of these lamps are

constructed for commercial voltages and for either direct or alternating The use of the tantalum lamp on alternating current is not

current.

60' Pig. 26.

75'

SO'

75°

60'

Distribution Curve of 132- Watt Type Westinghouse Nernst Single Glower.

Lamp.

always to be recommended as the service is unsatisfactory in some The minimum size of units for 110 volts is about 4 candle-

cases.

power

for the

carbon lamp, 20 candle-power for the metallic filament for the Nernst

lamp, and 50 candle-power (mean hemispherical)

Some of the metallic filament lamps are constructed for a consumption of as high as 250 watts, while the largest size of the Nernst lamp uses 528 watts. The light distribution of any of the

lamp.

units

is

flectors,

subject to considerable variation through the agency of rebut the Nernst lamp is ordinarily installed without a reflec-

120

Tnu

tor.

ti(

iK.iiriN^;

I'l:!*'

i:t.I"(

allv all of tin- ullur miit-t

Jlrctors aii
with reflectors have

The

of the lamps. consiilere*!

a.s

shown

Int'ii life

of

all

The

.satisfactory.

li^lit ilistrilMilioii <Mirv«-.s

connection with the

tin-

coniinercial

mitiimitm

life

iHtween

')(H)

hours and the

On

account of the slemlcr tilanunt.s einploynl

FIk'.

-7.

iis<'ful lif«' is f,'enerally

9p

7p

60*

n-

caiulli'-jxjwiT use-

lii^li

curves of

in

of

(»f

•_•:

ile.scri|>tion

lamps i|escrilH*«l is is seldom less than and

.'»(M)

I

.(KKI

in the metallic

7p

hours.

filament

60'

of LiKht fnuu Multiple-Glower West In kIiou.sc Nornst I.anip!i »lih 4 Glower. No. 1, 2 Glower: N'o. J, :5 Glower: No. Globes.

I>isirii>iitii)n

8' (.'lear

.'!,

lamj)s thev are not

made

for

low canille-j>owcrs

at

commercial

vol-

The

introduction of transformers for the purpose of chaiij^in^ the circuit voltafjc to one suitaMe for low candU'-power units has not

ta;,'«-s.

hecome

at all general as yet in this country.

SPIXIAL LAMPS The country

and

it

.Mcrcur_\ is

I.

|iiit

lamp mercury vapor, rendered

lhi>.

nnrcuiy va|>or lamp

in

this

on llic market Ity the Cooper-Ilewitt Company used to a considcralile extent for industrial illumination.

of an electric curn-iit lhrouj,'h

form

Tlic

amp.

l-'.lcctric

is lieiuf^'

In this

\apor

lamp

il. is

iiicande.Mcnt hy the pas-sapIn its stiindani

the soun-e of light.

consists of a long glass iul>c from which

carefully exhausted, and which contains a The mercury is held in u large inelidlic UKTcury. l>een

121

sniall l»ull>

at

the air ha.s ain«>unt

of

one end of

ELECTRIC LIGHTING

28

and forms the negative electrode in the direct-current lamp. is formed by an iron cup and the connections between the lamp terminals and the electrodes are of platinum where the tube

The

other electrode

connection passes through the glass. Fig. 28 gives the general appearance of a standard lamp having the following specifications: this

Total watts (110

volts, 3. .5

amperes)

Candle-power (M. H. with Watts per candle = 0.55

reflector)

Length of tube,

total

= 55

= 385 = 700

in.

Length of light-giving section Diameter of tube = 1 in.

=

45

in.

Height from lowest point of lamp to ceiling plate = 22 in. For 220-volt service two lamps are connected in series.

The First, the

mercui-y vapor, at the start, may be formed in two ways: lamp may be tipped so that a stream of mercury makes

contact between trodes

the

and mercury

is

two

elec-

vaporized

when the stream breaks. Second, by means of a high inductance and a quick break switch^ a very pass a current from one electrode to the

i\igh voltage sufficient to

Cooper-Hewitt Mercury Vapor

Fig. 28.

is

formed.

tilting

lamp lamps as

The

tilting

method

ii

•

xi

'

other through the vacuum, is mduced and the conducting vapor j.i

Lamp

i

of starting

is

preferred

and

this

brought about automatically in the more recent types of for automatically starting two Fig. 29 shows the connections

is

in series.

shown

A steadying

resistance

and reactance are connected

in this figure.

The mercury vapor lamp is constructed in rather large units, The the 55-volt, 3.5-ampere lamp being the smallest standard size. color of the light emitted is objectionable for some purposes as there is

an

entire absence of red rays

and

the light

is

practically monochro-

The

illumination from this type of lamp is excellent where sharp contrast or minute detail is to be brought out, and this fact has led to its introduction for such classes of lighting as silk mills and matic.

On

account of

color the application of this lamp is limited to the lighting of shops_, offices, and drafting rooms, or to dis-

cotton mills.'

its

122

LIBFniY KNl-IGHTKNINC. TMK WORI .f I!

HI

M'T

VI

W

Hunt, wa
\

,

I

I'niil

.i-.l

fur

III

'

l..ti

u;

'.a:

t

II

ELFXTRIC T.ICIITINC wlit-re play windows anrc 1)V tlii" color of

tlu* j;
shown It

U-

will not

is ust'«l

29

clian^if*! in a|i|M'ar-

a ronsidiTaMc

t«»

c-xtt-nt in

work on ut-connt of tlu- artinir proix-rlirs of llir li^'lit. pliotoj^rapliif SiK-iial reactanir-s must Ik* providt-tl for a nu-rc-ury arc laujp opiTdting on

circuits. sin^'K--pliasr, aiti'rnatiii^'-ciirrcnt

The Moore Tube

Lijjht.

The Moore

vacuum

—as a source

tulx"

(»f

discharjje

jiractical application

amount

of this dischar'^e to a system of lighting has involverl a larjje

FIk. 29.

wiring DIuctuih.

Two

11

AuUmiutii-

of the

through a

electricity

The

of illumination.

makes use

iijiht

—

familiar (Icissler tul>c ilischarije

Laiii|»f> l" S<'ri»'!*.

of consistent research on the part of the inventor and it has now heen that several installations have lM>tn made. l»roUf,'ht to such a staj,'e

The svstem

has

manv

interestiii'' features.

In the normal methotl of installation, a

dianutiT

is

nuidi-

up hy

connectiii},'

^'lass

tuhe

I

standard lengths of

lop-ther until the total desired lenj^th tniM-, which forms the .source of lij,'ht

is

reache«l,

when

in

and

J

inches in

^las-s tuhinjj

this

o|Kration,

continuous is

mounte
in the desired j)osition with rcs|)ect to the jilane of illumination.

manv

ca-scs the

tuhe forms a

the ceilinjj of the rooni to id>h- len^'lh. acdijil

lar^'e

Im- li^dited.

rcctan^jle 'I'll*'

tidx*

values running' from 10 to

123

mounted

may

Ik'

of

"J'JO feel.

In

ju>t U-nealh

any

reas«in-

In onler to

ELECTRIC LIGHTING

30

provide an electrical discharge through this tube it is customary to lead both ends of the tube to the high tension terminals of a transformer, the low tension side of which may be connected to the alternating-current lighting mains. This transformer is constructed so that the high tension terminals are not exposed and the current is led into the tube

by means

of platinum wires attached to carbon

The

electrodes are about eight inches in length. The ends of the tube and the high tension terminals are enclosed in a steel electrodes.

casing so as to effectually prevent anything from coming in contact with the high potential of the system. As stated, the low tension side

of the trans-

former nected Tube dtatributed in

form clcsiT0c^ to lertyhts ofsoo/eet

ccny

usual

is

to

conthe

60-cycle

lighting

mains.

If direct current is

used for distribution, a motor-

generator set for furnishing alternating current to the primary of the transformer

is

required.

Any

frequency from 60 cycles up

is

suitable for the operation of these tubes. At lower frequencies there 30. Diagram Showing Essential Features of the IMoore Light. 1 Ligliting Tube; 2. Transformer Case; 3. Lamp Terminals; 4. Transformer; 5, 6, 7, 8, Regulators.

Fig.

.

is

some appreciable variation

of

One other dethe light emitted. vice is necessary for the suitable

operation of this form of light and In order to maintain a constant presas the regulator. sure inside the tube, and such a constant pressure is necessary for its satisfactory operation, there must be some automatic device which

known

this

is

will

allow a small amount of gas to enter the tube at intervals while

in operation. The regulator accomplishes this purpose. Fig. 30 shows a diagram of the very simple connections of the system and it is

by the transformer, tube, and regu31 an view of the regulator, a description Fig. gives enlarged of which and its method of operation is given as follows:

gives the relative positions occupied lator.

is

A piece of |-inch glass tubing is supported vertically and its bottom end contracted into a f-inch glass tube which extends to the main lighting tube.

124

Ill

ruu iJianiNO

i:<

-^1

At the {Hiitit of contraction ut tht- huttoin of tin- {-inch tube tlu-rv U M-aliil by means of ccnu-nt a J -inch c»rliun j>hij;, tin* |K>rc>fiity of which in nol nn-iii enuugli to allow mercury to jiercolalc throuf;h it Lul which will (NTniit gmnsa ea-sily to pasD, due to the hi);h vacuunt of the lif^hting tube connected to the lower end of tin{)liii:, and approximately atmospheric jjressure ubnve it. This carbon I'luK normally completely covered with what wouM correspond to i-s

a thimbleful of mercury which 8imi)ly seals the pores of the carbon \>\ug, and therefore haa

nothing whatever to do with the conducting pri)j)erties of the gas in the main tube which Partly immers<'d in the pri)duces the light. mercury and concentric with the carbon plug, is another smaller and movable glas.s tube, the upi>er end of which is filled w ith soft iron wire, which acts as the core of a small solenoid connected in series with the transformer. The action of the solenoid

to

is

lift

the concentric

glass tube partly out of the mercury, the surface of which falls and thereby causes the

minute

shaped carbon plug

tip of the conical

to be slightly exposed for a second or two.

This expo-sure

is

allow

to

.suflicii-iit

n .small amount of gas to i-ntiT the tube, the current fleereases .slif^htly, and the

earhon

The

pluj^ is attain sealed.

above de.serihed takes of about one minute

when

process

intervals

j)laee at

the tube

is

in

ojM-ration.

The

eolor of the

lij^ht eniitteil

by the

tube dej)ends Uj)on the pas u.sed in it. The re^ilator is fitted with .some chtnii
arrangement whereby the proj)er gas

adinittrd to

tion.

it

Nitrof^en

when is

the lube

gives the highest ellieieney

emitted

when

in oj)era-

gas

is

(he

and the

u.sed

is

(iilu-

light

yellowish

KiVuI.ttliiK Vnlx-o.

Air gives a pink appearance (o

in color.

the tuU-

this

is

employi-d when

dio.xiile is employed when a white light is desirttl. IX gives gem-ral data nii tin- M«M»re tuU' light. The

and carbon

Tabli'

advatitagcs cljiimcd for this light arc: High ellicient-y, gmxl

low intrinsic brilliancy.

185

(xilor,

and

ELECTRIC LIGHTING

32

TABLE

IX

Data on the Moore Tube Light Length of Tube

TKic LK.nTixr.

i:ij:(

Hire

tla- turri'iit

thf bottom

33

u.s pus-sing from tlit- t«p mrlxm to arrow ami sigius. \\f (iiid, in the the by the most of (Ik- li},'ht issues from the tip of the

is

a.ssuined

oiu* as iiulicati-d

direct-iurniit arc,

tliat

and this portion is known as the cralrr positive carl)on, or electnxle. This erater lias a temperature of from .'i,(KJ(J° to3,o()()° C'., of the are. the temperature at whieh tlie carbon vaporizes, and gives fully S() to ho% of the light furnished by the arc. The negative carlnin In-comes

one is hollowed out to form pointed at the same time thai the positive the crater, and it is also incandescent but not to as great a degn-e as Hctwci-n the electrodes there is a the positive carl)on. arc the r^^^ r—rr light, proper, and this

—

band of

r-i

|

is

violet

-

surrounded bv a luminous

zone of a golden yellow cohjr. arc proper does not fur-

The nish

5%

more than

when

emitted

of the light

200

30O

carl)on

pure

electrodes are used.

The carbons away

arc

consumed

or

the

passage

of

positive

carbon

sumed about

worn

current,

„

\

Y

/

the

con-

being

/

"^

the

l)y

v

.

y\


twice as rapidly

as the negative.

The light distribution curve of a dlrtvt-CUrrnit arc, taken

in

shown

in Kig. 33.

is

given

a

vertical

olT at

plane,

Here

it is

^lK• 33.

Distribution Curve f..r D. Ijunu' (Vertical lliiiio)

C

.\rr

is

seen that the

maximum amount

an angle of about alP from the

carbon .shutting oil' ilie rays of ward from (he latir.

light ihai :irc

vertical,

of light

the negative

thrown directly liown-

(

If

alternating current

is

use«l, the

and there

and

n<-galive alternately, forme.l. l)oth carbons giving olV the

consumed an

at

about the same

nltrnuitiiiff-riirrrnt nrr is

rate.

is

upper carbon U'comcs positive n«»
same amount

The

slu)wn in

of light

l"'ig.

Ining curve of

aii.l

light distril)Ution

31.

we must have not Arc-Lamp Mechanisms, in a praclital lamp the arc. I»ut also nieans for su| rel="nofollow">only a |)air of carbons for producing |M)rting

these carl)ons, together with suitable arrangements for leading

ELECTRIC LIGHTING

34

them and for maintaining them at the proper distance carbons are kept separated the proper distance by the

the current to apart.

The

operating mechanisms which must perform the following functions:

The carbons must be in contact, or be brought when the current first flows. 2. They must be separated at the right distance 1.

into contact, to start

the arc

to

form a proper arc

immediately afterward.

Fig. 34.

Distribution Curve for A. C. Arc

Lamp

(Vertical Plane).

The carbons must be fed to the arc as they are consumed. The circuit should be open or closed when the carbons are consumed, depending on the method of power distribution. 3. 4.

entirely

The feeding of the carbons may be done by hand, as is the case some stereopticons using an arc, but for ordinary illumination the It is made striking and maintaining of the arc must be automatic. in

so in

all

cases

by means of solenoids acting against the force of gravity There are an endless number of such mechanisms,

or against springs.

128

ELl-XTUU: Ll(.illlN(j liiit

a ftw only will

into throt'

\n-

ilfscrilKtJ jierr.

'riity

35

may

Ix,-

roughly divided

cla.s.ses:

riiochani8inH.

1.

Sliiiiit

2.

Si-rics mi'diaiiisiii.t.

3.

DifTerential

Shunt

iiiL'chuiii.sni8.

In shunt lamps, the oarlMias an- h.ld apart turned on, and tlw cirfiiit is closed through a

Mrrli(nii.iin,H.

bt'forr tlu' curn-nt

is

solenoid conneitt'd in across the

+

-V

gap so formed. All (jf the current must pass through this coil at first, and the plunger of the

^AyWwUvWWW

is arranged to draw the carhons together, thus starting

solenoid

The

the arc.

and

j)ull

of the solenoid

springs are adjusted U) maintain the arc at its that of th

•

proper length.

Such lamps have the disadvantage of a high resistance at the start

and

—

ohms

laO

more

or

are difhcult to start

—

on series

circuits, ilue to the

They

re(|uire
high voltage tend to maintain

a constant voltage at the arc, hut

do not aid the
in

it:j

regulation, so that the arcs are liahle to Im- a little unsteady.

Serici

Mtch(nil.sm.s.

With

FIk. 35.

SorUlM M«vhaiil«jn for

An-

.series-lamp mechanisin, the carbons are together when the himp

D C

I^iiiip.

the

is first

started aiu' the current,

the series coil, sej)arati's th»' electrodes, striking the arc. flowing When the arc is too long, the resistance is increased and the
Inweretl so that the pull of the solenoiil is weakened and the carlH)ns This type of lamp can Ih" nsetl only on constantfeed together. potetitial systems. I'ig. 3')

diagnim

is

factured

l>y

.shows a diagram of the conni-ction of such a lamp. This one of the lamps maiui-

illustrative of tin- eoiuiecliun of

the

Western KIcctric ('<»mpany,

isn

for use

on a

dirvct-currerit,

ELECTRIC LIGHTING

36

The symbols + and — refer to the termiconstant-potential system. nals of the lamp, and the lamp must be so connected that the current

R is a series resistance, flows from the top carbon to the bottom one. means of the shunt G. and adjustable for different voltages by B and are the controlling solenoids connected in series with the arc.

D

F

A

C

is the are the positive and negative carbons respectively, while // off. is the on and of the switch for turning the current plunger

and / the carbon clutch, being what is known as a

solenoids this

carbon-feed lamp. are together when

KJ

the

current

plunger

is

is

The

A

excessive,

drawn up

lenoids, lifting the

carbons

is first

closed,

and the

into the so-

carbon

B

until

the resistance of the arc lowers the

current to such a value that the pull of the solenoid just counter-

balances the weight of the plunger

and carbon.

G must be so adjusted

that this point is reached when the arc is at its normal length.

Mechanisms. In Differential the differential lamp, the series and shunt mechanisms are combined, the carbons being together at the start, and the series coil arranged Fig. 36.

Differential 1).

C.

Mechanism

for

Arc Lamp.

so as to separate

shunt

coil is

them while

the

connected across the

arc, as before, to prevent the carbons from being drawn too far apart. This lamp operates only over a low-current range, but it tends to aid

the generator in

its

regulation.

shows a lamp having a differential control, this also being the diagram of a Western Electric Company arc lamp for a directFig. 36

Here S represents the shunt coil current, constant-potential system. and the series coil, the armature of the two magnets and A'

M

A being attached to a bell-crank, pivoted at B, and attached to the carbon clutch C. The pull of coil S tends to lower the carbon while that of

M raises the carbon, and the two are so adjusted that equilibrium 130

is

ELECTRii ij(;irnN(; n'aclinl wlu-n lit(f
tlit-

with an air

arc

of the All «tf the projxT li-n^'tli. lamps are or some to tla.sli|)ut, datiiping di'vice, prevent too is

rapitl nioveiiK'iits of the workiiij;

j)art.s.

The rnetiuMJ.s of supporting,' tin- carl)oijs and arc mav he divided into two classeij:

the

feeding them to

Roil-fcotl mocliatiiRtn.

1.

Curboii-fecil

tnuclmnUm.

Rod-Feed Mech a n ism.

Lamps

usin<; a rtxl

feed have

carl)oiis

supj)orte
the

upper hy a eonductinfj this rotl, the t(t

the rod

acts on

current bein<j fed

by means of a slidinj; Fig. 37 shows the ar-

rangement of

The

and the

mechanism

re<,'ulating

contact.

rixl,

rod

is

this type of feed.

shown

at R, the

sliding contact at R, and the carbon is attached to the rod at C.

These lamps have the advantage that carbons, which tlo not luivc a uniform crosssection or

smooth

exterior,

may

be used, but they possess the disadvantage of being very long in order to accommodate till-

k<

rod.

The

als»)

be

make

a

hmI imist

clean so as

|)f

to

Fli;. :^7.

MivhaiiUwi.

Koil-Fco.1

good contact with the brush. Cnrlioti-Fccd Merliani.'nii.

In carlM)n-feed lam|)s

tin*

contntlling

me<'hanism acts on the carbons diredly through some fortn of eluleh such as is shown at (' in Fig. .'{S. This damp grips the carlMni when it

is lifted,

is

relea.sed.

but allows the carbon to slip through I*'or

this

type of feed

llu-

it

when

have a uniform eross-scrtion as well as a smcM>th curn-nt .short

mav

be h d

lo the

carbun bv means of a

carbon holder.

i.n

(he tensitm

carlton nuist U- stniight ext«'rior.

and

The

ilexible lea«l an«l n

ELECTRIC LIGHTING

38

TYPES OF ARC LAMPS Arc lamps are constructed

to operate

systems when connected

nating-current are also made in both the open

By an open

arc

is

on direct-current or

in series or in multiple.

and the

:iS.

meant an arc lamp

Enclosed Arc

Lamp

alter-

They

enclosed forms. in

which the arc

to the atmosphere, while in the enclosed arc

Fig.

8

is

exposed

an inner or enclosing

with CiirbonFeed Mechanism.

globe surrounds the arc, and this globe is covered with a cap which renders it nearly air-tight. Fig. 38 is a good example of an enclosed arc as manufactured l)y the General Electric Company. Direct=Current Arcs.

Open Types

of Arcs

for

direct-current

systems were the first to be used to any great extent. Wlien used thev are always connected in series, and are run from some form of

133

KLKCTRIC LIGHTING sjx'cial

39

arc niiichiiu', a tli-scription of which ma}'

of l)viianio Elfftric

MachiiuTV."

Kach himp

in the

l>c

found

iti

*'Tvpe3

nei<,'hl)orh(>o
tion,

may l>e etjnnected to one machine is limite
of lam|)s that

as

many

as

lamps are run from one machine, hut even

12'>

tiiis

si/e

not so eflicient as one of i;reater capacity. Such j^nerators are usually wound for ().() or 0.() amperes. Since the carlHjns of [generator

is

are exposed to the air at the arc, they are rapidly consumed, rajuiring that they Ik> renewed daily for this type of lamp. Duiibh'-carboii

In order to increase the

arcs.

life

of the early

form of arc lamp without usinfj; too long a carbon, the douhle-carbtjn This type uses two sets of carhons, Ixjth si-ts ty[>e was introduced. one mechanism so arranged that when one pair of the elecconsumed the other is put into service. At present nearly forms of the open arc lamp have disappeared on account of the

licing fed l)y

trodes all

is

better service rendered

by the enclosed

arc.

Enclosed arcs for series systems are constructed much the same as the open lamp, and are controlled l)y either shunt or dilferential

mechanism.

They require a voltage from OS to 7') at the arc, and are constructed for from o to (i.S amj)eres. usually They also rerpiire a constant-
them

This resistance

any

circuit.

must have some resistance connecttni

in

keep the voltage at the arc at its pro[>er value. made adjustable so that the lamj)S may be used on

to

is

shown

Its lo<-ation is clearly

in Fig. 3K,

one

coil

U-ing

{(Mated alK)Ve, the other below the operating solenoids. Alternating-Current Arcs. These do not dilfer greatly in eonstriKliiiii

When

(hr din(t-
fniiii

iron or other ujetal

parts are used in the controlling mechanism, they must Ik> laminated or so constnu'ted jis to keej) down induced or e
might

lie s«'t

up

in

the solenoids are

from funning n oid winding.

them.

For

wound, are

this

reason the metal s|mh»Is, on which

close«l .se<'onilary to the

On

some

point to prevc-nt them primary forme«| by the solen-

slotted a(

constant-|)otenlial circuits a n-active coil

133

is

used

ELECTRIC LIGHTING

40

in place of a part of the resistance for cutting

down

the

voUage

at the

arc.

Interchangeable Arc. Interchangeable arcs are manufactured which may be readily adjusted so as to operate on either direct or alternating current, and on voltages from 110 to 220. Two lamps may be run in series on 220-volt circuits.

The different

distribution of light,

lamps

the distribution

and

the resulting illumination for the

just considered, will

be taken up

later.

Aside from

and quality

of light, the enclosed arc has the advanthat the carbons consumed so rapidly as in the open lamp are not tage because the oxygen is soon exhausted from the inner globe and the

combustion of the carbon

from 80

to

is

greatly decreased.

100 hours without retrimming.

TABLE X Rating of Enclosed Arcs

They

will

burn

ELECTRIC LKillTING

41

Full Arcs, 2.(XX) cniHlle-jKiwer taking 9 5 to 10 uinjxi. or 450- ISO watt*. Half Area, 1,200 caiulle-power taking Co to 7 ainiM. or 325-350 watu.

These

fan«IK--[K)\vor ratings arc iiukIi Um}

iR-arly 1,2U()

ami

ami

Ifss

tliis

reason, the

fM)Wcr

than this

c)f

atul

run more

mean

if tht>

ampere

the hinip.

lii^li,

point of inaxiiiuiin intensitv

7lM», resjK'ftivfly, f<»r tlic

It

For sphrrical candlf-powt-r Ik* taken. or watt rating is now use«] to indicate the is now rc<(nnmen(Je(l that sfM'cifications f()r

should he hased upon the illumination pnxluced. This considered later under the toj)ic of street lighting. Enclosed

street lighting

point is arcs use from 3 to 6.o amperes, hut the voltage at the arc is higher than for the open lanij). Tahle X gives some data on enclosed arcs

on coastant-potential

circuits.

The

Efficiency.

efliciency o* arc

lamps

is

given as follows:

Direct-Current Arc (enclosed) 2.9 watts per candle-power. .Mternating-Current .\rc (enclosed) 2.95 watts fier candle-power. Direct-f'urrent .Arc fojwn) .G-1.25 watts

Carbons for

.Arc

jx-'r

Carbons are

Lamps.

candle-power.

either

moulded or forced

known

from a

as petroleum coke or from similar materials j)ro«luct such as lampblack. The material is thoroughly dried by heating to a high temj)erature, then ground to a find powder, and combined with some substance such as pitch which binds the fine particles of carbon After this mi.xture

together.

The

j)owiler

is

put in

steel

is again ground it is ready for moulding. moulds and heated until it takes the form

of a paste, when the necessary pressure is a|)plied to the moulds. Kor the forced carbons, the powder is formed into c-yliiiders which nrv

placed in machines which force the material through a die .so arrange*! 'I'iie force*! carl)ons are *)fti'n made

as to give the desire*! diameter.

with a core of .some special

carbon proper has been or forced, niu>t I'he

.se<'tion, f*'e<|

and

lamp.

ehang*' the the are

Im-

can-fully

carbon

force*!

niat*'rial, this

is

core b*-ing added after the

Tlic carbons, whetln-r tnouldetl

(inl^lnij.

baked

to drive olF all

always more uniform

in

volatile matter.

i|uali(v

;iiid

*"n>s.s-

ty|M> of carlxxi which nuist Ik* us*'*! in the *'arlHmTh*- arial seems t*'»

is tin-

«|UJility

of light,

and being more

reatlily volulilizcxl, keepv;

from wandering.

I'laling ni*>uld*-*l

of «arb*)ns with

forms for (he

*'*>p|MT

is

.sometimes

purjMts*- of in*rea.sing

llu-

by protecting the carb*>n near the are. prol*>nging

186

n'.sort*"*!

t*>

for

*-on*lu«(ivi(v, un*l, tlu- life.

ELECTRIC LIGHTING

42

The Flaming Arc. In the carbon are the arc proper gives out but a small percentage of the total amount of light emitted. In order to obtain a light in which more of the source of luminosity is in the experiments have been made with the use of electrodes impregnated with certain salts, as well as with electrodes of a material arc

itself,

different than carbon.

The

result of these experiments has

been

to

place upon the market the flaming arc lamps and the luminous arc lamps lamps of high candle-power, good efficiency, and giving various colors of light. These lamps may be put in two classes One class

—

:

uses carbon electrodes, these electrodes being impregnated with certain salts which add luminosity to the arc, or else fitted with cores

contain

the

required

which

material;

the other class

covering lamps which do not employ carbon, the most notable example being the

magnetite arc which uses a copper segment as one electrode and a

PorceZairt Afeial

magnetite

Economize f

Fig. 39.

Diagram

of

Bremer Fiaming Arc.

an angle, and the other

as

the

other

Flaming arcs of the first class made in two general types:

are

One placed at

stick

electrode.

in

in

which the electrodes are

which the carbons are placed

one above the other as in the ordinary arc lamp. The term luminous arc is usually applied to arcs of the flaming t}^e in which the electrodes are placed one above the other. The minor modifications as introduced

by the various manufacturers are numerous and include

such features as a magazine supply of electrodes by which a new pair may be automatically introduced when one pair is consumed; feed

and control mechanisms; etc. The flaming arc presents a special problem since the vapors given off by the lamp may condense on the glassware and form a partially opaque coating, or they may interfere with the control mechanism.

Bremer Arc.

The Bremer

flaming arc lamp was introduced and since some of its principles are incorporated commercially in many of the lamps on the market to-day, it will be briefly described here. The diagram shown in Fig. 39 illustrates the main features of in 1899,

136

Kl.lXTUK LKillTING this laiii|).

I'lii'

fU'ftrtxN's an- iuoiiiitf<| at

13

an angle and an

fltftrt>-

alnivf the are for the nuignt't plac*'*! pnr|)4is4> of keeping the arc from anil the economizer, an
throwing the

flector,

light

downward. The economizer senes to and thus increases the life of the elec-

limit the air sup|)lied to the arc

The

was suggested hv the carbons a was formed which gave slag impregnated trouble when the electrodes were mounted in the usual maimer. By tHMles.

inclined jjosition of the carhons

fart that in the

the

using

electrotles

in

this position there is little if

any obstruction to the which passes di-

\

light

downward

rectly

from

the arc.

Bremer's original electrodes contained

compounds

of

strontium,

magnesium,

as

etc.,

well

calcium,

ployed

in

lamps

y

j(

em-

various

tile

ditfer

to-day

greatly in their

Some

so'

as boracic

Electro
acid.

o' /o'

eo'~9o*' BO'

make-u|).

FIr. 40.

Dlstrll)iitlr)ii

Ciirvi-sof a I.iimlnous Arc.

u.se

impregnated carbons, others use carbons witii a core containing the flaming maThe life of metallic wires arc aihlrd in some ca.ses. teri.ils, and electnxles for flaming lamps is not great, (lej)ending ujioii their length and somewhat upon the ty|tc of lam|). The maximum life t)f the treateil

carbons

is

in the

neigliborhood of

l2l)

hours.

is yellow when calused as the main impregnating compound, and the njajority of (he lamj)s installed us(> electrtnles giving a yellow light. By employing more strontium, a wA or pink light is pnMluceil, while

The

cium

if

:i

from

th«'

flaming an-

salts are

white light

most

The

<'o|or of the light

eflicieiit

is

wanted, bariunt

service

salts are iiscd.

Calcium gives the this and Itarium.

and strontium «onH's In'tween

distrilmtion curves in

l-'ig.

Id illustrate the relative e<.n)nuiuivs

1M7

ELECTRIC LIGHTING

44

Modern

of the different materials.

15%

of

added material and

it is

electrodes contain not

customary

more than

to find the salts applied

as a core to the pure carbon sticks. The electrodes are made of a small diameter in order to maintain a steady light and this partially accounts for their short life.

The

feeding mechanisms employed differ greatly.

classified as: Clock, gravity-feed, clutch,

anisms.

Fig.

41

illustrates

They may be

motor, and hot-wire mech-

a clock mechanism. ferential

This

mechanism

in

a dif-

is

which the

sluint coils act to release a detent

which allows the electrodes down and when they come

/

to feed

in con-

the series coils separate them to the proper extent for maintaining tact

a suitable arc.

In the gravity feed

an electromagnet is used to operate one carbon in springing the arc and the other carbon

is

fed

by

gravity,

being prevented from dropping too far by means of a special rib

it

formed on the electrode which comes in contact with a part of the

structure.

lamp emclutch mechanism but

Gravity feed

is

also

ployed in the here the carbons are held in one

Fig. 41.

Clock Feeding Mechanism Luminous Arc Lamp.

for

position by an electrically operated clutch which releases them only when the current

is

sufficiently

reduced by In the

the lengthening of the arc.

hot-wire lamp, the wire

is

usually in series with the arc; the contrac-

and expansion of this wire is balanced against a spring and the arc is regulated by such contraction or expansion of the wire. Such a lamp is suitable for either direct or alternating current. In the motor mechanism, as applied to alternating-current lamps, a metallic disk is actuated by differential magnets and its motion is transmitted tion

to the electrodes to

lengthen or shorten the arc accordingly as the

force exerted

by the series or shunt coils predominates. Magnetite Arc. The magnetite arc employs a copper disk as

138

'^

V.HH

m 3 O X I/)

I

ee

M

< X U

(is

« 3

o 0.

< J in

.

.

z " "-

-3

a i •

< ^ c

§

is Ou >

::

_3 >J z z "" ee o Ku

tid

£>-

K U Id

a z <

o

•^

,::

KLKC rUK one elcctnKlf, and a

LKiirriNO

inaffru'titr stick

t«»

whicli titanium salLs are usually

is

used as

tin-

other eleetrtMh-.

45

— fornittl

a
by forcing

ma^jiietitc,

into a thin sheet steel tub*'

This lamp

j:^vi-s

—

a luminous are of

not corLsumitl as rapidly that the result with as the treate*! carlions magnetite latn[>s do not ij(Kxl

eUifieticv anil the magnetite electrode

require trimming as frc<jurntly.

Tin-

life

is

of the magnetite electro<Jc

L'(M) lujurs. A diagram of as at present manufactured manufactured the General Klectric as of this the connections hy lamp is

Starling /

from 170

to

'

Magnet

tV

[

[

^^^ Pig. 42.

Tornpanv low. its

Magiietlto Arc I.«nip

The

magnetite electnnle is phuvd U'to prevent coppiT electrode has just the prop
is

The

ItlaKrniii «f C^mnertloiiK for

shown

in Fig. 42.

luing destroy«
undue conden.sation

of the arc vajxir.

i(

is not large enougli to cau.se Direct curn-nt must U> u.sjti

with this lamp, the current |)a.ssing from the copper to the magnetite. Tahle XI gives some general data on (lu- (laming arc, while Figs. I.',

and

14 give typieal dislrihulion (ur\es.

llaming arc over lamps tising pure earhon

Tin- a«lvaintages of the ileclriKles an-: Miglj efli-

heller color of lighl for eiency; Utter light distril)Ution; and

189

some

ELECTRIC LIGHTING

46

purposes, unit than

A is

greater

amount

of light

can be obtained from a single

practical with the carbon arc.

The

disadvantages

lie

in the frequent trimming required and the expense of electrodes. Flaming arcs have been introduced abroad, especially in Germany, to a much greater extent than in the United States.

TABLE

XI

General Data on Flaming Arcs Volts

ELF.rTRIC LIGHTINn any iuhiiIht of fircuits can Ik- run from om? machine or ami apparatus can Ik* l)uilt for any voltage aiul cjf any customary, however, to build transformers of

43

60'

75'

90'

75'

bus bars, It Is

not

having a capac-

this tyjx*

Distribution Curve for FlaniiiiKArc

Fig. 43.

set of size.

ec

Lamp.

greater than one hundred (l.Ci-anipere lamps tx'cause of the high voltage which would have to be induced in the secondary for a larger ity

number

of lamps.

Fig. 4') gives a dia-

gram of

of the

a

in

constant-<'urrent in

o'

tran.su.sc

Flictric

10*

for

lighting purposes is the one tnanufactured by the (leiieral

^

The

service.

former most

Direct current series circuit. LiQht ["tstrihuttcn \ \

traas-

singleH'oil

fonner

Luminous Arc Lamp

connection

30'

Com40'

pany and commonly known as a tub traii.sfiirmrr.

rtinovrd

I''ig.

frniii

Mi

(he

I''i»r.

50' 60'

4'l.

50'

DlHtrii'MM

:rM

.

•

.1

4-

^O'

Aiiiivnv

T.'V-Nolt. .Muk'ii*-lil<< l.uMiliioiiN .\n- l.aiii|>

shows such

a transformer (tlouble-<-«iil

ty|>«')

when

cas**.

Referring to Fig. are comiecteil

20'

so'

acro.s.s

Hi,

.1

form the primaries which

movable

coils li are the .secondaries

the fixed coils

the line; the

141

ELECTRIC LIGHTING

48

There is a repulsion of the coils B by the the current flows in both circuits and this force is bal-

connected to the lamps.

A when

coils

anced by means of the weights at W, so that the coils B take a position On light such that the normal current will flow in the secondary. loads, a low voltage is sufficient, hence the secondary coils are close

SECONDARY —x-x—x—X— X—X— LAMPS

together near the middle of the machine and there is a

LIGHTNING ARRESTER

heavy \Mien

(^ ARC AMMETER

magnetic

leakage.

of the

lamps are

all

on, the coils take the position shown when the leak-

CURRENT TRANSFORMER OMIT FOR 25 LIGHTS

age

is

a

voltage a

CIRCUTING ^ OPEN PLUG SWITCHES

first

minimum and the maximum. When

starting up, the trans-

former is short-circuited and

SHORT CIRCUITING PLUG SWITCH

the secondary coils brought The short

close together.

CONSTANT CURRENT TRANSFORMER

circuit is

the

then removed and take

coils

corresponding

on the

RESISTANCE

a position to

the

load

line.

These transformers regufrom full load to J rated

FUSE

late

load within ^V ampere of

normal current, and can be run on short circuit for

POTENTIAL

TRANSFORMER CFUSE

i

CPRIMARY PLUG SWITCH several hours without over-

PRIMARY

T

BACK VIEW Fig. 45.

heating.

AViring

Diagram

The

efficiency

is

given as 9G% for 100-light transformers and 94.6% for

for Single-Coil

Transformer.

50-light transformers at full factor of the system is from 76 to 78% on full to the great amount of magnetic leakage at less than

The power

load.

load, and,

load

—owing

the effect of leakage being the same as the effect of an inductance in the primary the power factor is greatly reduced, falling full

to

62%

at I load,

Standard

—

44%

at ^ load,

and

24%

at i load.

sizes are for capacities of 25-, 35-, 50-, 75-,

ampere enclosed arcs, and they are also

142

made

and 100-6.6

for lower currents in

KLia ruic LK.iniNd

\'.)

9

I t c s

t

c

Ma

ELECTRIC LIGHTING

50

the neighborhood of 3.3 amperes for incandescent lamps. The low factor of such a system on light loads shows that a transformer

power

should be selected of such a capacity that it will be fully or nearly The primary winding can be constructed fully loaded at all times. for

any voltage and the open

circuit voltages of the secondaries are

as follows: 25 light transformer, 2,300 volts. 35 3,200 50 4,600

The

50-, 75-,

and

75 light transformer, 6,900 volts. " " 100 " 9,200

100-light transformers are arranged for multiple

two circuits and the vol-

circuit operation,

used in

series,

tages at full load reach 4,100 for each circuit

on the 100-light

machine.

The second

system,

used

for series distribution on

circuits alternating-current consists of a constant-potential transformer, stepping down the line voltage to that required for the total number of lamps

on

the

volts series

system, allowing

83

each lamp, and in with the lamps is a

for

reactive coil, the reactance of

which

is

automatically reguis increased

lated, as the load Fig. 47.

Current Regulator for A. C. Series Distribution Systems.

Fig. 47

stant.

shows such a regulator and Fig. 48 shows

lator connected in circuit.

ment

or decreased, in order to keep the current in the line con-

The

this reguvaried by the moveor less iron in the magnetic

inductance

of the coil so as to include

more

is

Since the inductance in series with the lamps is high on light loads, the power factor is greatly reduced as in the constant-current transformer; and the circuits should, preferably, be run fully loaded. circuit.

60

to

65 lamps on a circuit

is

the usual

maximum

limit.

WTiile used primarily for arc-light circuits, the

144

same systems,

Ki.Kc-niic LKMITlXr;

lower currents, are very readily applied to series incan-

for


51

descent systems.

The

iiitHKluction of certain (laming or

luminous arcs rwjuiring

direct current for their operation has led to the use of the

ricHjur

connection

in

with

series

circuits

A constant-c-urrent transformer systems. constant current in its secondproper

is

mercury arc

on alternating-c-urrent used to regulate for the

ary winding, and this secondary current is rectified by means of the mercury arc the

rectifier for

recent

outfits

immersed

in

this rectifier

lamp

oil

was

for

In the

circuit.

the rectifier

tubes are

While

cooling.

introduced for

first

C.P. STEP UP OR STt-PCXDWN TRANSFORMER

the operation of luminous arc lamps, there is no reason why it should not

he used with anv series lamp

kicking

re(|uiriiig

direct current, provided the .system

is

designed for the current taken by su( h cial

2.')-,

ciency, transformer S')'^l to 009^,

and

I

tunc

at a

70%.

diagram of the

a

rectifier

~ll-'\ riif\

To-light

jj^

[MJ

UCHTNINC arrester:

effi-

rectifier tube,

and operate

factor of from ().j% to

gives

and

50-,

They have a combined

circuits.

.

LATOR

this

constructed for

of

CI RCCU

system any commerfrequency may be used. Sets are

With

lamj)s.

power

Fig. 40

circuit

and

connections used with a single,f.

fir. .is. wiring niain^m .siiowIhr intnxluctloii of tlio Current Utvulator.

ollttlt.

A\uhiplc-Sc'rics

or

.several lanij)s in .series,

Series-Multiple

and

tlu-.se .scries

Systems.

groups

These combine

in mulliple, or .several

Iam[>s in nuiltiple and these multiple groups in li.ivc bill ;i limited a|>|>lir,iti()ii.

.scri«-s,

rcsp«'ctively.

Thcv

Multiple or Parallel Systems of I)istril)uti»>n. Uy far the largest in .service are connecte«l to parallel .systems of tli.s-

numlM-r of lamps tribulioii.

In this .system, the units are conncct«-
leading to (he l)us bars at the station, or to the .secondaries of ct»nFig. '>() shows a
connected

in

parallel.

The

current di-liviTcd by the machine de-

140

ELECTRIC LIGHTING

52

pends directly on the number of lamps connected

in service, the vol-

tage of the system being kept constant. Inasmuch as the flow of current in a conductor

is

always accom-

panied by a

\//o-^zS AC Bt/sses

fall

of potential equal to the product of

Tube Tanff

the current flow-

ing into the resistance of the con-

Trcfns Jf^'^>\Load

Arreslir/^•?Tiynefe-r corl-

Load

necied ioATTim case STafzc--

r^

, ® SwiJcnes —@— ShoT^ Circtyii

maIa^t^wv^

:^M

Z>7SC

^myrteier-

V

foT- &0% 7zor?.

v>

lamps

end

of the

at the

system shown will not

have as

a

voltage

high

a-nd

tV

(hictor, the

Load Con yicc*

impressed

upon

them

those

as

nearer

the

chine.

ma-

This

drop in potential is the most seri-

Fi/sts Ifiaaliififl

5i^7ic?3 'e%

ous obstacle that Fig. 49.

weiring

Diagram for A. C. System Showing tion of Mercury -Vrc Rectifier.

Iiitrixluc-

we have to overcome in multiple systems,

various schemes have been adopted to aid in this regulation.

systems 1.

2. '.i.

4.

may

be classified as

and The

:

Cylindrical conductors, parallel feeding. Conical " Cylindrical anti-parallel feeding. " " " Conical

In the cylindrical conductor, parallel-feeding system, the conductors, A, B,C, D, Fig. 50, are of the same size throughout and are

same end by the generator. The voltage is a minimum lamps E and a maximum at the lamps F; the value of the

fed at the at the

voltage at any lamp being readily calculated. By a conical or tapering conductor is meant a conductor whose

diameter

is so proportioned throughout its length that the current, divided by the cross-section, or the current density, is a constant

146

II

Swell a

Miiaiitilv. ^IIlalI^•^

.sizt'.s

i

< I

oiuliHiur

of win- as

i-.

Xi

appnixiiuatctl in praclitt' bv using

tlir ciirrtMit in tlu* liiirs Ix'i-onu'S |fs.s.

to systi-ni, ilu- currftit is fed

un anti-paralUI

In

I'HIC F.KMI'IMNC

the lumps from

ends of the .system, as sh«i\vii in Ki;,'. .'»!. n|i|)<)site In order to take advantajje of a hi<;her Multiple W ire S\stcms. of power to the li;:htinf; einuits, three- and voltage for distrilmlion five-wire svstenis

have been intriMJueed, the three-wire .system U-ing In this .system,

to a verv lar^'e extent.

iis«'d

thri'c-

eonduetors are

used, the voltaj^e from each

conductor

outside

conductor

neutral

miildle hcini:

as

.same

the

for

fi

ParallW Kcctling Sytftfin.

Fig. 50.

this.

system the amount

this

of copper recjuired for a

en

a

Fi{^.

simple parallel .system. of .')2 gives a dia<jram

Bv

B

the

to

number

«)f

is

lamps

j,'iv-

from

eighths of required

.Viitl-pan-llel Ki-cilInK

KIg. 51.

ve-si.\tcenths to three-

amount

the

for a two-wire dis-

tribution,

depending on the

size of the neu ral con-

riint -»

t

ductor.

System.

The saving

iri-

S:
of

with the disadvantages of the .system copjH-r together treatcfl in the paper on "Tower Transmi.ssion."

is

more

fully

ILLUMIN.ATION Illumination

which

aiils

l«'

dc(ine
the utline

Not only the

color.

the

in

may

arrangement

r)f


the units,

bnl

of the subject of illumination. Init of Illumination. TIk-

and

ramlli

it-

value

is

the

distance of one foot from I'll.-

given

a

ilie

must be

ipuility

of light (|Uanlily the |)erccption of of the light, as well as

eonsidere
unit

amount

and

and

of

illumination

of light falling

soun e of

light

on a

is

the

/<»<>/-

.surfatv at

one candle-iM»wer

a

in value.

law of inverse .sf|uan's— namely, that the illumination frtun a of the distinuv fnun the as the .sourcj- vari«s

— shows thai

^urct,

scpnire inversely the illumination at a distanc«- of two feet fn>m a

117

ELECTRIC LIGHTING

54

For further candle-power unit is .25 foot-candles. see of inverse the law of sideration squares, "Photometry." single

Illumination

may

be

classified

as useful

—when

con-

used for the

ordinary purposes of furnishing light for carrying on work, taking when used for decorative lighting the place of daylight; and scenic

—

such as stage lighting, etc. The two divisions are not, as a rule, distinct, but the one is combined with the other. Intrinsic

Brightness.

By

brightness is meant the surface of the light source. Table

intrinsic

amount of light emitted per unit XII gives the intrinsic brightness

of several light sources.

TABLE Intrinsic Brilliancies in

Source

XII

Candle-Power per Square Inch

ELECTRIC LICIITING I

rifltiiii)M

)itl'iis((l

virv importaiit

is

inasniiK'h as diirusttl interiors.

Light

is

'I'liis

li|;lit

form of

plavs an

rcflettion

in

seen in

is

tin-

iin|)(jrtaiit

55

.>tu«lv

of illuniinatidn

part in

tlu*

lighting of

many photometer

sereens.

when passing through semi-transparent shades

also tlitTused

or screens. In considering reflected light, we find that, if the surface on light falls is coloreil, the reHey the absorption of some of the colors. Since, as has Ixt-n

which the its

said, in interior lighting the reflected light

source of illumination, this illumination

and

forms a large part of the depend upon the nature

will

the color of the reflecting surfaces.

Whenever

reflected

is

light

from a surface, either by direct or

amount of light is absorbed by the surface. amount of white light reflected from different

difTused reflection, a certain

Table XIII gives the materials.

TABLE

XIII

Relative Reflectia}; Power Matkiiial

Whito hlottinu

s-j

puiH-r

so G2 50 40 36

^\'l^itl• cartri(,lj;c

pajKr Chniiiie yellow paper ( )raiip(' paiKT Vclliiw wall pai)f'r

pink pajHT Yellow eanlhoard Light l)lue cardboard I'riH-rald preen paper Lifjhl

Dark brown

pafjer. Verrnili<jii paf>or

IMin-preen paper. Hlack pa|»er

.

.U)

•Jo

IS 13

,

1_'

IJ

.

r ,)

IMaek cloth l?l!i(k

1

velvet

-'

1

i( is setii that the light-colored papers reflect the but of the darker colors only y«'llow has a companilivelv light well, Black velvet has the lowest value, but high c(M-fIicient of reflection.

I-'rom this laliie

this

only holds

dark walls

when

the material

re«|uire a great«T

is

amount

free

fn»m dust.

H(H>ms with

of illuminating power, as will

In-

seen hiter. Usi'ful

illumination

may

be

heads:

140

considered

under the following

ELECTRIC LIGHTING

5G

2.

Residence Lighting. Lighting of Public Halls,

3.

Street Lighting.

1.

Drafting Rooms, Shops,

Offices,

etc.

RESIDENCE LIGHTING Type

of

Lamps.

The lamps used

limited to the less powerful units

for this class of lighting are

— namely,

candle-power from S

incandescent or Nernst

50 per

unit. These should be so to shaded as the intrinsic The always keep brightness low. intrinsic brilliancy should seldom exceed 2 to 3 candle-power per

lamps

varying in

square inch, and

its

to

reduction

is usually accomplished by appropriate are so shading. lights powerful as to be uneconomical for small rooms, while the color of the mercury-vapor light is an additional

Arc

objection to

its

use.

Plan of Illumination. as to give a brilliant

and

Lamps may be

fairly

selected

uniform illumination

in a

and so located room but this ;

an uneconomical scheme, and the one more commonly employed is to furnish a uniform, though comparatively weak, ground illumination, and to reinforce this at points where it is necessary or desirable. is

The

latter plan is satisfactory in almost nomical of the two.

While the use where desirable, the same room.

of units of different

all

cases

power

is

and

to

the

more eco-

be recommended,

should not be used for lighting As an exaggerated case, the use of arc with incandescent lamps might be mentioned. The arcs being so much whiter than the incandescent lamps, the latter appear distinctly yellow when lights differing in color

the two are viewed at the

same

time.

Calculation of Illumination.

In determining the value of illumi-

tlie amount of remust be considered for the given location of the lamps. Following is a formula based on the coefficient of reflection of the walls of the room, which serves for preliminary calculations:

nation, not only the candle-power of the units, but

flected light

1

c.p. 1

= I

=

c.p. /;;

d

= =

-

r

^

Illumination in foot-candles.

=

Candle-power of the

unit.

Coefficient of reflection of the walls.

distance from the unit in

feet.

150

rr.ECTRIC LKJIITING WluTf

st'Vcral

lM'(()mt-<

fiiiiiiiila

or,

r.p.

:

units of

(/j,

«aiiilir-jMiwrr art-

iisitl

III 1

rf,

Naiiir

lhi.s

1

= ^

where

tin-

57

d.,,

1

1

•"

iP

1

^

"^

ttc, e(|ual

"^ 1

rf^,

^/=,

-

it

from the point consiih-red

tlic (Jistanc-es

to

the various li^ht sources. If the lamps are of dilFereiit eaiulU'-|>o\ver, the ilhiniinatioii inav be detenniiicd hv eoinbiiiiii'' the ilhiiniiiation

from is

source as calculated separately.

eacli

uiitler

given

The above

of

"Arrangement metluxl

take account of the

is

ande

An

e.\anij)Ie of calculation

Lamps."

not strictly accurate because it does not at whicji the li
sources strikes the assumed plane of illumination. light

perpendicular to the plane, the fornuda

is

= -^givcs

I

cor-

If

fornmla becomes

the

the ray of

(/ is the angle which the ray of light makes with a line the light source perpendicular to the assumed plane,

rect values.

drawn from then

If

I

=

'''^'

^^'2'^^^"

'

1''»'refore.

by

multiplying the candle-power value of each light source in the dire(tion of the illuminated jioint l)y the cosine of each angle a, a more

accurate result will be obtained. It is is

of

readily .seen that the elTcct of reflecteil light from the ceilings

more importance than

that

from the

floor of a

The

room.

value

formula, will ^ary from ^\{Yy^ to \{)^[ but for riHtms with a fairly light finish ')()^l may be taken as a goinl average value. The amount of illumination will dejM-iid on the use to U- made of

of

/;.

the

in the al)ove

room.

reading,

nation of

<

)nc

,

foot-
when measured normal ..")

illumination

foot-candle on a plane

.5

feet

ground illumination. The illumination from sunlight fn»m whil«' clouds is from L'O foot-<-andles up, whih- that «lue

cienl

light

is

in iId*

nei^hborlxMMl of

.().'{

for

and probably an from the tliMir forms

to the page,

fiH rel="nofollow">tH-andles.

It

is i,ot

easy

illumi-

a sufli-

rellwteil to iiuhmi-

ixwsibh* to

priNluce artificially a light eipiivalent to daylight on ai-count of the

\r>\

ELECTRIC LIGHTING

58

amount

great

of energy that

would be required and the

difficulty of

obtaining proper diffusion.

room that has method and it is taken of the angle at which gives very accurate results if account the light from each source strikes the plane of illumination and if

The method

of calculating the illumination of a is known as the point-bij-point

just been described

the light distribution curves of the units, and the value of k, have been Under these conditions the calculations becarefully determined.

come extended and complicated and methods only approximate, but simpler in their application, are being introduced.

One method,

which gives good results when applied to fairly large interiors, makes the flux of light from the light sources the basis of calculation of the average illumination.

measured in lumens and a lumen may be defined which must fall on one square foot of surface in order to produce a uniform illumination of an intensity of one footA source of light giving one candle-power in every direction candle. and placed at the center of a sphere of one foot radius would give an illumination of one foot-candle at every point in the surface of the and the total flux of light would be 47r, or 12.57, lumens since

Flux of light amount of

as the

is

light

sphere the area of the sphere would be

47r,

or 12.57, sq.

ft.

A

lamp giving

one mean spherical candle-power gives a flux of 12.57 lumens and the total flux of light from any source is obtained by multiplying its

mean

spherical candle-power

by

12.57.

In calculating illumination

determine the illumination on a plane about 30 customary inches from the floor for desk work, and about 42 inches from the to

it is

floor for the display of

number

of

lumens

goods on counters.

falling

on

this

If

we determine the total this number by

plane and divide

the area of the plane, we obtain the average illumination in footcandles. This of course tells us nothing about the maximum or

minimum

value of the illumination and such values must be obtained

than that if they are desired. Reflected light, other covered by the distribution curve of the light unit including its re-

by other methods flector, is

usually neglected in this method of calculation. assume that in large rooms the light coming from the

We may

of 75 degrees from the vertical reaches the plane In smaller rooms this angle should be reduced to

lamp within an angle of illumination.

about 60 degrees.

In order to determine the flux of light within this

152

FT.FrTRIC LUiHTING uii^'U-

u lioussetiu diagram, which

this IJy the ineaiLS of

source within

tiic

diagram

angU' assumed

mean

is

tlie

59

desc-ribttl hiter,

should

drawn.

Ix*

avi-rage candle-[X)W'er of the light Ix*

may

and

readily determined

tliis

12.57, will give the flu.x of light in lumciLS.

vahie, muhiphed hy This metluKl of calculation, together with some guides for its rapid M<-ssrs. Cravath and Laasingh in the application, is described hy

"Transactions of the Illuminating Engineering Society,

same

The

I'.MJS."

authorities give the following useful datii:

To

determine the watts recjuired

j)er

square foot of floor area, by the constants given

desired nuiltiply the intensity of illumination

as follows:

INTENSITY CONSTANTS FOR INCANDESCENT

LAMPS

Tungsten lamps rated at 1.25 watts per horizontal candle-power; clear prismatic reflectors, either bowl or concentrating; large room; light ceiling; dark walls; lamps pendant; height from 8 to 15 feet

Same with very

Tungsten lamps rated at 1.25 watts per horizontal candle-power; prismatic bowl reflectors enameled; large room; light ceiling; dark walU; lamps pendant, hoiglit from S to 15 feet

Same with

.25

20

light walls

verj' light walls

29 23

Gem

lamps rated at 2.5 watts per horizontal candle-jMiwer; clear prismatic reflectors either concentrating or bowl; large room; light ceiling; dark walls; lamps pendant; height from S to 15 feet. ... Same with very light walls Carbon filament lamps rated at 3.1 watts per horizontal canille-power;

55

45

bowl or concentrating; liglU ceiling; .65 dark wali.s; l.n m; lamps pendant height from 8 to 15 feet 55 Same with very 11Bare carbon fdament lamps rated at .3.1 watts |)er horizontal candlcix)wer; no rrflcctors; large room; very light ceiling and walls; 75 to 1 .5 height from 10 to 14 feet .25 to 2.0 Same; small room; me
.

;

.

.

.

1

i

>

.

INTENSITY CONSTANTS lOR ARC 5-am()ere, encloMj-d, din-ct-current arc on opal oiitrr globe; no n-di-rtor: large

walls

li.iglK

from 9 to

LAMPS

lU)-vult circuit; clear inner,

room;

light

ceiling;

medmiu 50

14 feel

.\ii Arrangcnicni
uf the

numU'r

of units re«piired,

and the

1&3

inartistic cfTcct.

Wc

arc

ELECTRIC LIGHTING

60

limited to chandeliers, side lights, or ceiling lights, in the majority of cases, with table or reading lamps for special illumination.

and the

^^^len ceiling lamps are used reflector or reflector lamp

form of

to

is

ceilings are high,

be recommended.

some

In any

case where the coefficient of reflection of the ceilings

I

is

less

than

40%,

it is

more economical

\Mien lamps are mounted on chandeliers, the illumination is far from to use reflectors.

uniform, being a maximum in the neighborhood of the chandelier and a minimum at the corners of the room.

*

f|

"*

<M

"

'

By combining chande-

with side lights

generally possible to ^ satisfactory arrangement of lighting for IV)§^^^ small or medium-sized rooms. ^ liers

As a check on

the candle-power have the following

- required, we

I

it is

in

lamps

:

T For brilliant illumination allow one candletwo square feet of floor space. In some Diagram Showing Po^'^r per Method of Calculatuig particular cases, such as ball rooms, this may be Room Illumination. increased to one candle-power per square foot. For general illumination allow one candle-power for four square feet of floor space, and strengthen this illumination with the Fig. 53.

aid of special lamps as required. ceilings will modify these figures to

As an example

The location some extent.

of

lamps and the height of

of the calculation of the illu-

mination of a room with different arrangements of the units of light,

assume a room 16

feet

<esquare, 12 feet high, and with walls having a

coefficient of reflection of

Consider

50%.

first

the illumination on a plane 3 feet above the floor when lighted by a single group of lights

mounted

at the center of the

the ceiling.

candle

is

we have

If

a

minimum

room

3 feet below

value of

.5

foot-

required at the corner of the room, the equation .0

=

Since d

method outlined)

(first

..1

1 c.

p-

=i/8'

-X 12.8^

+

:

8'

1

+

6'

_

.5

9 Q

1 '^'

/'see ^

^'^'

^"*

Diagram

8-c. p.

Side Wall.

Fig. 53)

154

for

I-amps on

Four

1

<

g

>:

Q

> z

fa

s

=>

o p u H '^ < Q Ko Cfi

b]

o

»}'

.ti

%^' ..

»

•a

fl

s < H U o < s

.3

a

> Q

o o K a z z o

M

^3

o o

O

e

p. 3

<,

>-

-

—

O

-r

= '^ =

a

/

^

art

/.

u e<

*^

a.

< z o r!^ a

<

?^8

Q 0.

«-

<

a

Aid

n 'a •J

J

,

FLKfTIUr Solving the c.

Thre<'

p.

icMTlvr;

valm-

aljovt- for the

=_

I

(»f r.

••'

X

.5

we have

p.,

H2

gi

41

=--

lamps would serve

Uj-euiulU'-jxnver

this

pur|)ose very

well. Deteriiiiiiiiifj

the illumination directly umlt-r

()-

1

-

tin-

lamj).

we have:

.ib

..)

2.7 foot-eandles, or five times the value of the illumination at the

corners of the room.

Next consider four 8-oantlle-power

lainj)s

walls S feet alx)ve the floor, as .shown in

illumination at the center of the the

Fij^'.

hxated on the side 54.

Calculating: the

a plane three feet above

room on

we have:

floor,

^

^

^

rf»

=

8'

+ S

1

"89" 5-

^

"^

"^

^~8Q

=

04

+

X

2

4

X

^

Hi)'

"^89

=

T^Ts'

= 89

25

.72 foot-carulles

8!)

The

room wouM

illumination at the ct)rner of the ^

"

^^W^W^ -Mo

= 8(-J- + -7^ <S9

In a similar

)

X

2

=

^

'

343 .4")

he-

1-..)

fiH)t-
.j4.)

manner

tht-

illuiuinatit)n

may

he (-dculattd for any

taken and curves

in the nK)m, or a series of points may ploC(c\ul siiowin^ the distribution of the li^'ht. as well as the areas having the same illumination. Where re(iiu
trihution curve of the

jM)Wer

lamp must

in dilFcrcnt ilin-'tions.

Ik- usvi\

Kij;.

')')

for determining: the ean
shows illumination curves

for

Meridian lamp as manufacture or 'I'liis is a form of nllector lamj) made in two sizes, pativ. tin-

.'»<>

eandlc-[M)wcr.

I''ij:.

'>(»

^ives

the

distribution curves

Similar incandescent (•andli'-powcr unit. nianufacturi-
1&5

hunps

ar*-

for

tin*

now

.'»(>-

Im-imj:

ELECTRIC LIGHTING

62

Table XIV gives desirable data in connection with the use of the Meridian lamp.

Fig. 55.

IlUmiiuation Curves for a G. E. Meridian

Lamp.

TABLE XIV Illuminating Data for Meridian

Lamps

,1

very ar«-mai.

...m,\

OiluT

inetluxl.

n\c ur.HTiNo

' :

.\licii

iiutliiMis

tin-

an-

sysU'in «»fteii

i)f

illiiniiiiatioii aiitiuLs

.simpler

and

of this

sufiicieutly act-urdte

for practical work.

FiR.

Dr.

Distrllnitlon

5ft.

T-()ui> Hell

gives

Curve

tlic

lighting:

f<»r

ii

G. K.

riO-c. p.

following in connection with residence

TABLE XV Residence Lighting Data .

Ruuu Hall, 15'

X

Lihriiry, 20'

Uccfpiioii

20'.

X

2U'_ l.V

ri)()in,

Mn-^ic roorii, 20'

.<

DiiiiiiK roDiii, l.V Hilliiiril r.M.iii, l.V

X

2.">'

X

1 l.V..

.

.

20'

.

20'.

\'l,Tch

H.Mlr.M)mrt (G), 15' Dr.

X

X

l.V.

lO'Xlo'

.S.T

Mailiruiiin.T Kitrliiii. l.V I'iUitrv, II.'iIIm'^

(Vlliir

15', 10'

\

10'

.1

10'

,

•

X

IV 1.V

(

)

.

.

Meridian I^iiip.

ELECTRIC LIGHTING

64

LIGHTING OF PUBLIC HALLS, OFFICES, ETC. Lighting of public halls and other large interiors differs from the illumination of residences in that there is usually less reflected light, and, again, the distance of the light sources from the plane of illumination is generally greater if an artistic arrangement of the lights is to

This

be brought about.

The primary

object

is,

in turn reduces the direct illumination.

however, as

in residence lighting, to

produce

a fairly uniform ground illumination and to superimpose a stronger illumination where necessary. An illumination of .5 foot-candle for the ground illumination may be taken as a minimum. In the lighting of large rooms it is permissible to use larger light units, such as arc lamps and high candle-power Nernst or incan-

descent units, while for factory lighting and drafting rooms, where the color of the light is not so essential, the Cooper-Hewitt lamp is

being introduced. High candle-power reflector lamps, such as the tungsten lamp, are being used to a large extent for offices and drafting

rooms.

The choice of Where the

work.

lamps are

to

are often the fully

lisj;ht

be preferred to the arc or vapor lamps, though the latter more efficient. AMien arcs are used, they must be care-

shaded so as

shadows due

lamp depends on the nature of the must be steadv, incandescent or Nernst

the type of

doing away with the strong lamp mechanism, and to reduce the Such shading will be taken up under the head-

to diffuse the light,

to portions of the

intrinsic brightness.

ing "Shades and Reflectors." Arcs are sometimes preferable to incandescent lamps when colored objects are to be illuminated, as in

and display windows. In locating lamps for this class of lighting, much depends on the nature of the building and on the degree of economy to be observed. For preliminary determination of the location of groups, or the illumi-

stores

when certain arrangement of the units is assumed, the prinoutlined under "Residence Lighting" may be applied. It has ciples been found that actual, measurements show results approximating nation

closely such calculated values.

\Mien arcs are used they should be placed to twenty-five feet

when used

fairly high,

twenty

and the

ceilings

for general illumination

are high. They should be supplied with reflectors so as to utilize Wlien used for drafting-room the light ordinarily thrown upwards.

158

I! I'C'IMMC

work,

tlu'V

the floor,

slioiihl

ami

Ik*

susjM'iulnl

rare s[M-
IrieuiKleseeiit latnj)s lij,'hts

inu.st In-

may

Im-

I

'(

MI'TIW;

from

r-^'i

twi-lvr to

taken to arraiifjetl

or inouiitetl on chandeliers, or they

fiftiH-rj

feet alxive

tlitTuse the light.

fjroups, either as side

in

may

Ije

arranged

u.s

a frieze

running around the HMiin a fiw feet Ix-low the eeiling. The la.st named arrangement of lights is one that may Ik- made arli>tie, hut it is

uneeonomital and when used should serve

the lights

may

b<'

for the grouncl illumiiui-

he useil fur this style of ui»rk and entirely concealed from view, the reflecting prop-

Kelleitor lights

tiou oiilv.

may

utilized for distrihuting the light erty of the walls iK'iiig

reiling

lights

should

are high. especially when the ceilings Indirect li'diting is emidoved to lii'htin"

we mean

where neede<J.

prcfcraMy he supplied with

some

extent.

reflectors,

Bv

indirect

a svstem af illumination in which the light sources

are coiuealeil and the light from them

is

reflected to the

njom hy

the

are wal.'s, or ceilings, or other surfaces; or in which the light sources the latter case In the diffusing plate plaied above a difVusing panel. In some ca.ses the walls them.selves apf ^ars to Ix' the .source of light. .so to form the refliH:tors for the light as are shajx'd ami constructed uni 5 (cove lighting), hut in others all of the reflecting surfaces, except the side walls and ceiling, are made portions of the lanij) fixtures. Tables XVI and X\II give data on arc and mercury-va|x)r lai

i|)S

for lighting large rooms.

ac'Mallv installf
Table XVII

refers to arc lights as

ELECTRIC LIGHTING

66

*

00

H

O

o o o

'^ _; CI t- ^3 5? "' to CO to

o

to

o

00

b "

m

CI

G

CO

^

O

2

CO

O

B<

to t^ ro

^

" {J

<J<

o

«<

r->

o CO

-H

-H

to CO Tf Tl* "O

in c^

*

-3 0> S ^ CO

^ O

^ I—o b r

C3 «

I

•<:

Q 00

a n

3 o oS O lO .

o

•a

o o 00 o (M

CO CO

•
IN

O O

o

00 CO CO C)

'

Li

is

O

1C5 (N to

^ o ^

^

C)

•

to

o

C-J

CI _;

o o M * 00

Q5

1^ C5 Q, CO "o ,ir

o

'-'

o

2oo CO

o

a

CJ

2 a

E I

cs

.J

wo u to

"3 t^

O

u

> < o

C)

w S

O

C)

uo

-<)

CI

< Q

o

G JS

> a < o w o

o

o

M

O

CI

CJ "*

_;

— S

CJ C) rt CO CO JC"

01

jd O) "^

o

Q

SKYLIGHT Tlie

upper

curb measures G'

0*

illustration

G'

A

shows the layout of a flat pitched .«kylight whose tiie run of the rafter or length of the glass being

— 0* X 7' — 6",

on a horizontal

wide

WORK *

line.

Five bars are required, making the glass 15 inches AB and CD is shown below.

working section through

It will

the roofing

be noticed in the section through

and flanged around the

inside of

AR tiie

tliat

the flashing

is

locked to

angle iron construction; over

rests, bolted through the angle iron as shown, tho capped and soldered to avoid leakage. The same construction is used in the section through CI), with tho excep-

this the

curb of the skylight

bolt being

when the flashing cannot be made in one manner indicated, over the fireproof blocks.

tion, that in the

•The

itluiitratiou referred to will

piece, a cross lock

bo found oa tho back of

lai

Ihia pa^*-

is

placed

coMSTnucTion drawing aHowiriG layout OF FLAT .5KYL1GH.T ARD i^lLTMOD OF FA5TEnin.G FLASamG on AnGLE.

mon

GOA5TRUGTIOn.

—^1 l£>-shmG,

Condensas-tion'

vSecTion \T.n<2-.

Secrion end.

i;hrouo,h lov/<s,r of curb A.-S

u.pper

end

rhrou^h of

C-D

FOR EXPLANATION OF THIS PROBLEM SEE BACK OF PAGE

curb

SHEET METAL

WORK

SKYLIGHT WORK \M»ere formerly skylij^lits were cnmstructe*! from wrod^lit iron or wood, to-
c«)[)j)er.

Sheet metal

skylif^hts,

having hy their

jieculiar

construction lightness and strength, are superior to inm and woollen lights; su|)erior to iron lights, inasmuch as there is hardly any exjjan-

and wooden lights, because they are fire, water and condensation* proof, and being less clumsy, admit more liglu. ^riic small Ix^dy of metal usetl in the construction of the bar and

sion or contraction of the metal to cause leaks or hreiikage of glass; su|)erior to

curb ami the provisions which can be made to carry off the inside condensation, make slieet metal skylights superior to all others constructed from diiferent material.

CONSTRUCTION The if

the

construction of a slieet metal skylight patterns for tlie various

is

a very simple matter,

intersections are properly devel-

For example,

oped.

shown

in

Fig.

14.')

the

bar

consists of

a

piece of sheet metal having the rcfjuired stretchout and length,

and bent by .special machinery, on the regular cornice brake,

or

into the .shaj)e .shown,

which rep-

resents strength an
llicleast

amount of

from the inside when the tlie glius.s,

while

In Fig.

]\ ]\

li(j,

C

warm

Fig.

1 J.'i.

air strikes against t\\v

I

ci>lil

ig.

un.

surface of

shovv the rabbets or glas.s-rest for the glasA. C is a re-enforcing strip, which is «imn1 to li(»ld

ih:<

tJic

SHEET IMETAL WORK

134

O O

together and impart to it great rigidity. When skylight bars are required to bridge long spans, an internal core is made of in Fig. 147, which adds to its sheet metal and placed as shown at

two walls

A

weight-sustaining power.

In

B B

this figure

shows the glass

laid

on

a bed of putty with the metal cap C C C, resting snugly against the glass,

fastened in position by the

rivet or bolt

D

D.

Wliere a very

large span is to be bridged a bar similar to that shown in Fig. 148 is

used.

A

heavy core plate

of j-inch thick metal

is

or bolted to the bar at construction,

A made

used, riveted

B

and B.

the various

all

terminate at the curb shown at

C Fig- 147.

in Fig. 149,

the

which

wooden frame

is

In bars

AB

fastened to

D E.

condensation gutters C C b, carry the water into outside through holes the to the internal gutter in the curb at a, thence 150 is shown a sectional In Fig. provided for this pm-pose at F F. of a view of the construction double-pitched

The

skylight.

in the bar

A

shows the ridge bar with a core

in

B the center and cap attached over the glass. in is used which or cross bar the shows clip the large skylights where it is impossible to get must r" where the and in one glass length, glass be protected and leakage prevented by means of the cross bar, the gutter of which conducts the water into the gutter of

the

main

bar,

thence outside the curb as before explained. C is the frame generally made of wood or angle iron

and covered by the metal roofer with

flash-

D

shows the skylight bar ing as shown at F. with core showing the glass and cap in position.

E is

the metal curb

condensation being against which the bars terminate, the through the holes shown.

let

out

In constructing pitched skylights having double pitch, or being In other words it is one-third hipped, the pitch is usually one-third.

164

^uv.KT Mrr\r

of

If

tlu- >|iiiii.

tht>

rttiiiirftl.

When

11

Hat

a

.skyliji;ht

.skyHj,'ht

is

huilt in

pitch is usually or iron frame anil a laiil

over

weif

IL' fet-t

rise in the center wuulil

The

it.

made

wmi-k'

ami one-third pitch were one-third of 12, or 4 feet.

wiile Im.*

tlie

the w^hmI

flat

skylight

jjlass

use
in

the construction of metallic .skyor lijjhts is usually J-inch rough cases some in hut rii)l)cd glass;

heavier glass If for

is useil.

any

rea.st)n

it is

desired

know

the weight of the various to thickness of glass, the following table will prove valuable. NN'eight of Koujrh (Mass Per

Square

Thickness

i iV Weight 2.

in •2\.

I

out.

in inches. i-

^-

^-

|)ounds. 3\. 5. 7.

^-

S'..

'•

^-

10. 12",.

B^ Y

FiR. 160.

10»

i::.'

SHEET METAL WORK

136

SHOP TOOLS In the smaller shops the bars are cut with the hand shears and formed up on the ordinary cornice brake. In the larger shops, the for the bars or curbs are cut on the large squaring strips required shears,

and the miters on the ends of these

known

as a miter cutter.

on a

single table,

strips are cut

on what

is

This machine consists of eight foot presses each press having a different set of dies for the purpose

The bars are then of cutting the various miters on the various bars. formed on what is known as a Drop Press in which the bar can be formed

in

two operations

to the length of 10 feet.

METHOD EMPLOYED The method

IN

OBTAINING THE PATTERNS

be employed in developing the patterns for the various skylights is by parallel lines. If, however, a dome, conservatory or circular skylight is required, the blanks for the various curbs, to

bars, and ventilators, are laid out by the Work, Part IV, under "Circular Work".

rule given in Sheet

Metal

VARIOUS SHAPES OF BARS In addition to the shapes of bars shown in Figs. 145 to 148 inclusive, there is shown in Fig. 151 a plain bar without any condensation gutters, the joint being at A.

rabbets of the bar, while

C

BB

represents the glass resting on the

shows another form of cap which covers

Fig. 153.

Fig. 152.

the joint between the bar and glass. Fig. 152 gives another form of bar in which the condensation gutters and bar are formed from one piece of metal with a locked hidden

seam

Fig. 153

at A.

shows a bar

on which no putty required when glazing. it is bent from one piece of metal with the seam at A, the glass B B D is the cap resting on the combination rabbets and gutters C C. which is fastened by means of the cleat E. These cleats are cut about It wall

is

^inch wide from

soft 14-oz copper,

166

and riveted

be noticed that

to the top of the bar

WOUK

•Iirir MI'.TAL

at F;

a >lot

tlifii

is

cut into

tin-

)

I

caii

as sluiwii from

the cap is pressed lirmly onto tlie down whicli holds the cap in |M)sition. tlifii

When ijuiretl,

as

a skvH;;ht

shown

is

raise
to h in Ki^;. I54;

ch-at

which raising

constnictetl in

K

tiirne
suslies are re-

the sides

re<juire
A

and

sash to he

tlie

are so constructe
obtained when

15<),

«t

ami the

};la.<>!

in Fig. loo, lialf l>ars arc

B. while the l)ars on each side of

Mil

whicli

is

closetl.

This

shown

is

an enlarge*! section through

Thus

in

Fig.

AB

in

AA

Fig. loG, represents the two half bars with condensation gutters as shown,

Fig. loo.

in

Fig. 154.

(^ C the locketl .seam taking place at B B. repre.sent the two half bars for the raising sash with the I) attachcaps etl to same, as shown, so that when the sash C C is close
D

FiR.

1.55.

EE

D

and the stationary half cover the jomt between the glass F F are the half caps soldered at a a to the bars C (' which bars. 1)

protect the joints between the gla.ss

II

11

and

tlic

bars

C

C.

VVRjOlS SliMMIS or CI R lis In

are

Figs.

shown

which are with I.')7

flat

I'vS

lo7,

and

1.'>M

a few sha|Hvs of ctirbs usi-tl

c«»nne<'tion

in

.\

skylights.

shows the curb

in

Fig.

for the thret*

sides of a Hat skylight, fornuti in

one

|)ii'<'e

with a joint

at

B. while

C

.shows the cap, fastt'tUMl as previously tlescrilM'
i.s

thick

and allows

tJie

wuter

U17

U>

run over.

In Fig. LVS,

A b

SHEET

138

INIETAL

WORK

another form of skylight formed in one piece and riveted at B; a shows the height at the lower end. In the previous figures the frame on which the metal curb rests is of wood, while in Fig. 159 the frame is

Fig. 157.

Fig. 158.

Fig. 159.

of angle iron shown at A. In tliis case the curb is slightly changed as shown at B ; bent in one piece, and riveted at C. In Figs. 160, 161; and 162 are shown various shapes of curbs for pitched skylights in addition to that shown in Fig. 149. A in Fig. 160 shows a curb formed in

one piece from a to & with a condensation hole or tube shown at B.

Fig. 160.

Fig. 161.

shown a

Fig. 162.

slightly modified shape A, with an offset to AMien a skylight is to be placed over an opening whose walls are brick, a gutter is usually placed around the wall, as

In Fig. 161

rest

is

on the curb at B.

168

SIIFI-T

to b to

c.

which

102, in

sh()\\ni in Fi^'.

a fitter, H,

MKTALWORK

139

A represents a section of tlie wall on which

hung, formed from one piece of metal, a.s shown from a On top of this tlie metal curb C is sohlereil, whicli Ls also i.s

fonnetl from

one piece with a

wooilen core

i<j

To

seam at /. shown at I).

lot-k

inside as

slippeil

stiffen this

FrtMu the

curb a

iasi«le

con-

densation gutter / a 14-oz. copjier tube runs through the curb, shown at d. The condensation from the gutter r in tiic bar, drips into tlie

tube d, into the main gutter H, from wliich outside by a leader.

out of

gutter

/,

veyed

to tlie

tlie

In Fig. 103

is

shown an enlarged

D

in Fig. l."). through C lower curb and C I) the .side

tion with Fig. Fig.

shows

103

K F

loO.

the

A

it is

c-on-

section of a raising sash, taken

103 shows the ridge bar, H the .sections of the bars explaine
in

h

upjjcr

frame of the raising sash,

fit-

ting onto the half ridjie bar

A.

On

each raising sash, at the upper end two hinges II

are riveted at

allow the

E and

.sash to raise

I,

which

or close

by means of a cord, rod, or J .shows the gearings.

K

lower frame of the sash over the curb B. |)unch'Hl

at

o

to

fitting

Holes are allow

the

condensation to escape int«» h, thence to the outside through

TIk. U>3.

the hinge II a hood or cap is placed which prevents Fig. KM .shows a .section through .\ H in Fig. 1(17 and repleakage. resents a hippe
C)ver

one-third pitch is meant a skylight whose altitude or height .\ H.isetpnil to one-third of the If the skylight was to have a pitch «if .span C I). one-fourth or one-lifth, then the altititde A H would espial oni»-fourth "

or one-fifth respectively of the span

The

(

O.

illustration .shows the construction of

a

hipj)etl .skylight

with

(' 1) is the curb; F. K ridge ventilat«)r which will be briefly descriln-d. the inside ventilator; F F die outside ventilator forming a cap over ihc

iiin

SHEET

140

IVIETAL

WORK

G shows the hood held in position by two cross braces H.

glass at a.

common bar on the rabbets of which the shows the condensation gutters on the bar J,

J represents a section of the glass

KK

rests,

L

Fig. 164.

which are notched out as shown

at M, thus allowing the drip to enter the gutter and discharge through the tube P. The foul air escapes under the hood as shown by the arrow.

N

G

Fig. 165.

170

I

DORMER ON MUSEE DE CLUNY, Built in the Fifteenth Century

PARIS, FRANCE

Note the Figure Sculpture at Sides of Dormer.

i u 3

I

8

o K

oz

i.

IT

r

: V.

=

= >a

Q - r S = —

a a

<

t

SIIKKT MK'I'M

AkIOtS STYLES

\

In Fi^. H'u) plact-il

on

:i

is

curl>

sluiwii wliat

made

In*

is

\\(

Ol

HI

i!;K

>KM.l(im>

kimwii as a single-pitdi

and

Itf^lit,

the car|)C'nter wliicli luis the ilesirnl

is

jiitcli.

Fig. 160.

'rhe.se .skylislit.s are chiefly u.setl

tration,

ami made

to

on

.steep rt)of.s a.s .sliown in

a \\(MKlen

.set <>n

furl).s

the

ilhi.s-

pitching the .same as the

A

FiR. 107.

roof, the

(

\\'ntilation

iirh first l)eing {la.shctj.

one or more

liglits l)y

means

is

obtainetl

of gearings, as sliown in Fig.

l(i.H.

FJK.

17

1

l)y

l.V).

raising

SHEET METAL WORK

142

Fig. 166

shows a double-pitch skylight. Ventilation is obtained at each end as shown at A. Fig. 167 shows a

by placing louvres

The corner bar C skylight with a ridge ventilator. bar; the small bar D, mitering against the corner bar, bar, while

E is called

itor skylight

the

common

is

called the hip

is

called the jack

Fig. 168 illustrates a hip

bar.

with glazed opening sashes for ventilation.

mon-

These sashes

can be opened or closed separately, by means of gearings similar to those

shown

In Fig. 169

in Fig. 177

is

shown the method of

raising

Fig. 169.

sashes in conservatories, greenhouses, applicable to both metal and of a photographer's skylight;

wooden if

etc.,

the

sashes.

same apparatus being Fig. 170

shows a view

desired, the vertical sashes

can be made

to open.

extension skylight at the rear of a store or building. The upper side and ends are flashed into the brick work and made water-tight with waterproof cement, while the lower side

In Fig. 171

rests

is

shown a

on the rear wall

to

flat

which

it is

172

fastened.

In some cases the rear

SHEET gutter

of cast iron, put

is

tlir

up hy

of No. 22 pilva!u/,e
the lM>ttoin of the jjutter

MirrAI.

and

143

iron workt-r, l)ul

2(>-o/..

colil-rolle*!

skylight,

usuully niiule copper. To receive

when

re<|uire
ami another

tliick.

e
two planks are not

is

it

wall should he c«»vere
tiie

two inches

\viK)den plate A, Ki^. 172. al>out .set

WORK

a cast iron flutter

shown

at B.

l»y

a

j^lank 'I'he

is u.se
slu)ws a hij)j)ed skyli;;ht without a ridfje ventilator, .set on a metal curh in which louvres have Keen place
tnav he

\7'^

made

When made

stationarv or movahle.

movahle. they are

' '

:

Imr. 170.

con.structed as

shown

shows them

in

17

Fij,'.

and

I,

in

which

A

.shows a pers|HH'tive view,

'

open. They are o|)erate«l hy the tpiada and h, which in turn are j)uIUn| up to the rants attached upri|^ht hars and down hy cords or chains work«-d from hclow. ^^hen a skylight |{

lias

closetl,

a very lonj; spati, as

iti

(

Ki^'.

17.">, it

is

constructeil as

shown

in Fijj.

repres«'nts a T-hcam which ean he tru.vsiNl if ne
which

up|MT

li^'ht

of the iijiper

.A

to the outside of the top of the lower skylight, the lij^'ht

fittinjj

over the <'urh

173

H

of the lower light.

curh

C

SHEET METAL WORK

144

In Fig. 177

is

shown the method

A

of applying the gearings

shows the side view of the metal or wooden sash partly opened,

B

the

Fig. 171.

end of the main

shaft,

and

C

the binder that fastens the

main

shaft to

D

shows the quadrant wheel attached to main the upright or rafter. shaft and E is the worm wheel, geared to the quadrant D, communicating

F

is

motion

to the

whole

shaft.

a hinged arm fastened to the

main

B

and hinged to the By turning the hand-whee

shaft

sash.

1

the sash can be opened at any angle.

DEVELOPMENT OF PATTERNS FOR A HIPPED SKYLIGHT The and

following

illustrations

text will explain the princi-

ples involved

in developing

the

patterns for the ventilator, curb,

hip bar,

and

common bar

cross

bar, jack bar, or

clip,

These

in

a

hipped skylight. princiare also applicable to any other form of light, whether flat, double-pitch, sing-le-oitch. etc. ples

174

SHEET METAL WORK In Fi^. 17S

is

shown

a

half

.se<'tii)n,

a

145

fjiuirtfr

phiii,

ami a

iJiiip)naI elevation of a hip har, inthuhnj; the patterns for tl»e curh, ami coinnion hars. '^Tlie method of niakinjij tliese drawinpi hi|), jack, will l>e exi)lainetl in detail, so that tlie student wlu) pays close attention

173

Fig wn'll

have no

pitch of

tlie

First

be, or

may

draw any center

C 4', ef|ual

out any patterns no matter what the what angle its plan may have. its A B, at right angles to which lay off

difficnlty in laying

skylight

to 12 inches.

line

A.'isuming that the light

is to

have one-third

FlK. 171.

nuike the distaniv

pitch, tlicn

asei'tion of [larallrl

li>

1

CI)

e<|Ual to

and
of 21 inches,

theconnnon )

1'^

and the inside

l»ar a.s

1

>

I.'

shown

intersei'ting the curl)

l>y

S inches which

shown fn)m a

se<'tion of the ventilator fn^ni

\7T>

is

on«Mhird

At right angles to I ) I' phur K, through which draw lini*s 1-'

to / at the Utttoni

to (i at the top.

At

SHEET METAL WXDRK

146

of the outside vent shown from hio I and the pleasure draw the section hood shown from mtop. X represents the section of the brace resting on i j to uphold the hood resting on it in the corner o. The condensa-

Fig. 175.

tion gutters of the

common

bar

E

are cut out at the bottom at 5' 6'

which allows the drip to go into the gutter d

e f oi the curb and pass out of the opening indicated by the arrow. Number the corners of each half of the common bar section E as shown, from 1 to 6 on each

through which draw

side,

D

lines

4' until

they inter-

sect the curb at the

bottom as

parallel to

shown by similar numbers 1' to 6', and the inside ventilator at the top by similar figures 1" to 6". This completes the one half-sec-

From this tion of the skylight. section the pattern for the com-

mon Fig. 176.

At right angles to stretchout of the section

D

4'

draw

bar can be obtained without

the plan, as follows: the Una I J upon wliich place the

E as shown by similar figures on I J. Through

and at right angles to I J, draw lines, and intersect drawn at right angles to D 4' from similarly numbered intersections V to 6' on the curb and 1" to 6" on the inside ventilator. Trace a line through points thus obtained then A* B* C^ D' will be the these small figures,

them by

lines

;

176

SUKKT MKr.\L for the (luninon liar in a

piitterii

would

\\T)HK

liippeil skvli^jlit.

147

'I'lie

same

inetluKi

a pattern were ilevelope*! for u flat or a «loul)leemploye*! From this same half section the pattern f«jr the curh is pitili li^lit. the stretchout i»f the various corners in tiie curb, ilevelope«l l)y takin;^ (J

h

l(f

'.V -I'

if

(•

r aiitl

il

by similar letters

A B

angles to

C

angles to

/.

and

and

draw

|»lacinj^

figures.

lines

A' froni similar

them on the center

Through

which

line

AB

as

shown

these divisions and at

intersect with lines

jKiints in the curl> section a

drawn j.

rij^ht

at right

'IVace a line

through points thus obtained; then K' F' the curl) to

shown

in the half section.

he punched into

light.

As

tlie

pattern between each light of glass in the skyc d turns up on c 4', u.se r as a center, and with

tlie

{x)rtion

I'^g.

the radius

r

.v

V

/ a will he the half pattern for represents the condensation hole

177.

strike the semicircle

shown.

AI)ove this semicircle

punch the hole \. Before the patterns can l>e obtained for the hip ami jack bars, a i|iiarfcr j)lan view nnist Ik- constr\icte
between the hip bar and curb, between the hip bar and and between the hip and jack bar. Therefore, fnun

vent, or ridge bar,

j)oint on the center line .V B as K, draw K 1/ at right angles to A B. the skylight forms a right angle in plan, draw from K, at an angle of 4.')°, the hip or iliagonal line K \'\ Take a tra<Mng t»f the ctmunon

any .Vs

bar line

with the various figures on same, ami j)lao that the ]Hiin(s I I <"t»me dinn'tlv on the hip as by K'. Through tlic various figures draw lines parallel to K 1°

se<'tion V.

K P

shown

in

177

1^

PATTERN FOR COMMON BAR

rrCUT FOR UPPER

OF JACK BAR

Fig. 178.

END

WORK

SlIKirr MK'IAI.

or»e-lialf

H

of which are

iiiterse<'tt*
vertical Hne^i tlrawii parallel to

l>y

fn)in similar jHjints of intersection

on the

IW

1'

to

on the curb, and

(5'

A

1" to 0*

shown res|)ectively in plan by Helow the hip line K 1° trace the

ventilator in the half section, as

interse<-tions 1° to

V

and

('t°

to

0''.

It shoulil he untlersto«>d that the opposite intersection as shown. section E' iti ])lan does not indicate the true profile t>f the hip bar (

whichinust heohtained

later),

hut

only j)lace« there to give

is

I

tlie

hori-

zontal distances in j)lan. In laying out the work in practice to full size, the up[)er half intersection of the hip bar in ])lan is all that is ret|uiretl. It will

section

be noticed that the

of intersections in j)lan and one half if the student will carefully follow

j)oints

have similar numbers, and

each point the method of these projections will become apparent. Having obtained the true j)oints of intersections in plan the next step is to obtain a diagonal elevation of the hip bar, from which a true To do this draw any section of the hip bar and pattern are obtained. line as

R

M

j)arallel

{joints 1° to G°

and

K 1°.

to

C

tion as the base line

4'

V to

This base

line

M has the same eleva-

R

has in the half section.

G^'

M

From

the various

in plan, erect lines at right angles to

K

1°

Now measuring in each and every crossing the line R indefinitely. in the half section take the various distances instance from the liiu' ( '

to jM.ints I) 1" 2" 3" 4"

V

.")"

and

(i"

at the top,

and

to iK)ints

1' 2'

3' 4'

">'

the biJttom, and place them in the diagonal elevation meason the similarly and every instance from the line R in each uring iiumberc
and

G' at

M

|X)ints

P

N r

2^ 3^ 4^

^

and G^

at the top,

and

1'' 2'' 3'' 4'"

')•

and tr

at

Through the points thus obtaineoints by lines as .sliown,

tlie

l)ottom.

which completes the diagonal elevation of the hip bar intersecting the curb and vent, or ridge. To obtain the true section of the hip bar,

K

take a tracing of the c<jmmon bar

shown by 1'

]'

Iv\

being careful

as shown.

Rnglf^

til

From

r r draw


or K' and place it in the |>osition the j)oints 1 4 at right angles to

to j)lace

the various j)oints in the se<-tion K' at right

lines intersecting similarly

shown from

shown; then V/

will

I

In

•"•

munberi'd lines

mi either

siile.

in tlie

ConiUH-t these

be the true profile of the hip bar.

Note

the di (Terence in the two profiles; the normal l''.' and the modititnl K'. Having obtaine<| the (rue profile F' the pattern for the hip bar i:« oiitairnil

by drawing the stretchout

170

line

O

V

at right angles 1'

1'.

SHEET METAL WORK

150

Fake the stretchout similar figures.

O

and place it on P as shown by these small figures and at right angles to

of the profile E*

Through

O P draw lines which

intersect by lines drawn at right angles to 1^ 1^ from similarly numbered points at top and bottom, thus obtaining the A line traced through the points tlius points of intersections shown. obtained, as shown by H* J^ K^ L^ will be the pattern for the hip bar.

For the pattern

common

for the jack bar, take

a tracing of the section of the

E

and place it in the position in plan as shown by E^ being careful to have the points 1 and 4 at right angles to the line 1^ 1°. It is immaterial how far the section E" is placed from the corner 2° as the intersection with the hip bar remains the same no matter how far bar

is placed one way or the other. Through the various corners in the section E- draw lines at right angles to the line 1° 1^ inter-

the section

secting one half of tlae hip bar on similarly numbered lines as shown by the intersections P2^3'^ 4^ 5^ 6^ and 1^ 2"^ 3-^ 4^ S*' andG'^; also inter-

secting the curb in plan at points 1^ to 6^. The intersection between the jack bar and curb in plan is not necessary in the development of the pattern as the lower cut in the pattern for the common bar is the

same

as the lower cut in the pattern for the jack bar.

shown

However, the

make a complete

drawing. At right angles to the line of the jack bar in plan, and from the various intersections with the hip bar, erect lines intersecting similarly numbered

intersection

is

lines in the

tions

in plan to

Thus from

section as shown.

shown from

P

to 6^ in plan,

erect

the various

vertical

lines

ing the bar in the half section at points shown from similar manner from the various points of intersections in plan, erect lines intersecting the

P

intersecintersect-

to 6^.

and

3'', 5"^,

In 6"'

bar in the half section at points

shown by 3"' 5'^ &. Connect these points in the half section, as shown, which represents the line of joint in the section between the hip and jack bars.

For the pattern for the upper cut of the jack bar, the same stretchout can be used as that used for the common bar. Therefore, at rio-ht angles to

draw

D 4' and

from the various intersections

lines intersecting similar

common

bar as shown by similar figures.

various intersections 3^ 5^ and right angles to

as

numbered

shown by

6"'

in the

P 2^

3''

4^

5''

and 6^

lines in the

pattern for the In similar manner from the

one half

section,

draw

lines at

D 4' intersecting similarly numbered lines in the pattern

3'^ 5"^

and

Q'^.

Trace

180

lines

from point

to point,

then the

SIIKKT cut

shown from N'

MKTAL WORK

to I" will represt'tit the

151

miter for that part sliown iu

and the cut shown from I" to ()• in the pattern will cut for that part shown in plan from 2*- to 0'', the The represent lower cut of the jack bar remains the same as that shown in the pattern. plan from

2''

to G'

,

The half pattern for the em nf the hooil is shown in Fij;. 17'.>, ami obtained as follows: Draw any vertical line as A H, Ujxjn which I

is

place the stretchout of the section of the hood m n o p in Fij^. 178, as in Fi{^. 17!>. At right angles shown by similar letters m nop on A to A B and through tlie small letters draw lines, making them e<jual in \'>

from the line A B) to jM)ints having similar letters measuring from the center line A B. C'omiect jxjints shown in Fig. 170, which is the half j)attern for the end nf the hood. For the half pattern for the end of the outside ventilator, take tJie length, (measuring

in Fig. 178, also

I J

2*1

Tl

A"

HALF PAT T El FOR END OF HOOD

op]

m

HALF PATTERN FOR END OF OUTSIDE VENT

H

G HALF PATTERN FOR END OF INSIDE

VENT

B Fig. 179.

stretchout of A

/;'

k

Fig. 180. I

in Fig.

Fig. ISl.

17s ami jilace

it

on the

vertical line

.\

H

in

Fig. ISO as shown by similar

letters, tlirough which draw horizontal lines making them in length, measuring from A H, ecpial t«> similar letters in Fig. 178, also measuring from the center line .\ H. Connect

In the points as shown in Fig. ISO which is the desire
stretchout of which isobtainetl from

F

1" 2" 3" l" II (I in Fig. 17S.

the jjattern l>eing obtained as explained in connection with Figs. 17l) ami ISO.

When a skylight is to be constructed on which the bars are of such lengths that tlic glass cannot be obtained in one length, and n cross bar or clip is re<jnia«d as shown by B, in I'ig. l.*)(), which miters against the main

bar, the j)attern fnr this intersecting cut

181

is

obtaineil as

shown

in

SHEET METAL WORK

152

A

Let Fig. 182. represent the section of the main bar, B the elevation of the cross bar, and C its section. Note how this cross bar is bent so that the water follows the direction of the arrow, causing no leaks because the upper glass a is bedded in putty, while the lower light b is

capped by the top flange of the bar C (See Fig. 150). Number all of the comers of the section C as shown, from 1 to 8, from which points

draw horizontal At

lines cutting the

right angles to the lines in

main bar

A at points

1 to

8 as shown

B draw the vertical line D E upon which

2

1

4

3

C

8

-_Z^^

13";

PATTERN FOR CROSS BAR

e"i

E Fig. 182.

place the stretchout of the cross bar C, shown by similar figures, through which draw horizontal lines, intersecting them with Unes

drawn parallel to D E from similar numbered intersections against the main bar A, thus obtaining the points of intersections 1' to 8' in the Trace a line through points of intersections thus obtained pattern. which

be the pattern

will

In Fig. 183 turret sash

is

shown

for the

end cut of the cross bar.

shown a

carefully in Fig. 168 at A.

182

drawn working section of the These sashes are operated by

SHEET METAI. means of

chains or gearings from the

ct>rds,

thev turn l>eing

shown hy

S

11

vitling

he understamls the construe-

tion.

This

mmle

the pjvot on which

Tlie method of obtaining as omittwl, they are only stjuare and

for these saslies will l>e patterns which tlie student will have htitt miters

\>e

insitle,

in Fig. 1S3.

tlie

will

VA

^VOI{K

clear

n-*

trouble in developing, pro-

hy

the following explanation: A B represents the ujiper part of

I

on

turret proper with a drip bent

tlie

at B, against which the sashes close, and a double seam,

1

same, as shown as

shown

at

In

°1.^

A. which makes a tight

joint, takes out the twist in bending, and avoids any soldering. This upf in per part A B is indicated by '

Fig. 1G.S, over

183.

of fits

D

C.

over

tlie

183

which

wooden curb W, and

D

in

Fig. lOS.

represents

made from one double

is

in Fig.

represents the lower part

indicated by Fig.

XUY

turret proper or base,

tlie

B

which the gutter

shown by

placed as

the

E

is

in

lua_-.

muUion H

piece of metal ami

seaiiie
This mullion

the top and bcttom. joine
'r

to

is

cut, wliile tlie j)attern for

V.

-i)^

the bot-

FiK. 1S.1.

wouM represent a butt miter Before forming up this mullion the holes against the slant line i j. shoulil be punched in the sides to admit the U .'^. These mullit»ns tom

j)ivot

are

shown in position in Fig. KJS bv E etc V ( in Fig. 1S;.3 represents the .section of I'^.,

I

tlie

side of the sash Ih>Iow

the j)ivot T. Notice that tliis lower half of tlie siile of tlie siush has a lork attachment which h(X)ks into the flange of the mullion E at F.

While the |)ivot

T,

.side

of

tlie

hiLS the lock

sash

is

bent

in

one

piecx;,

omitted as shcwti by

((pens, the uj»per half of the sides turn

IH.<

.1

the uj)j>cr half, alxive the

K.

'llius

when

toward Uie inside

lus

tiie ."MLsh

.shown by

SHEET METAL WORK

154

the arrow at the top, while the lower half swings outward as shown by the arrow at the bottom. When the lower half closes, it locks as shown at F,

which makes a water-tight

joint;

but to obtain a water-tight joint

which the upper half, a cap is used, partly shown by L IVI, into This cap is of the sash closes as shown at M. of side half the upper fastened to the upper part of the mullion E with a projecting hood / for the

which

is

will have placed at the same angle as the sash shown by e e' and d cV or by the dotted lines.

when

it

is

opened as

The side of the sash just explained is shown in Fig. 168 at H. The pattern for the side of the sash has a square cut at the top, mitering with

H I at the bottom, in Fig.

183, the

same

as a square miter.

HI

of the sash. Note where the metal represents the section of the bottom is doubled as at h, against which the glass rests in line with the rabbet

on the

side of the sash.

This lower both ends.

shown

.section is

NO

in Fig.

A beaded edge is showTi at H which stiffens in Fig. 168 by G and has square cuts on it.

shown

in Fig.

168 by F.

183 shows the section of the top of the sash The flange in Fig. 183 is flush with the out-

N

side of the glass, thereby allowing

the glass to slide into the grooves in the sides of the sash. After the glass

is

in position the angle

tacked at n.

A leader

is

P

is

attached

Y as shown by B° in While the method of

to the gutter

Fig. 168.

construction IE

11

10

shown

in Fig. 183 is

employed, each shop has different methods; what we generally

^^'

have aimed

'

to give is the general construction in use, after

which, the student can plan his

which are apt

own

knowing

construction to suit the conditions

to arise. illustrations. Figs. 184 to 187, it will be explained the true lengths of the ventilator, ridge, hip, jack, and in a hipped skylight, no matter what size the skylight

In the following

how to obtain common bars

be. Using this rule only one set of patterns are required, as for example, those developed in connection with Figs. 178, 179, 180, and If, however, a skylight 181, which in this case has one-third pitch.

may

was required whose pitch was different than one-third, a new set of patterns would have to be developed, to which the rule above mention-

184

SHEET METAL WORK e
155

woulil also be iipplicaltlc for .skyli^lits nf tlmt particular pitcli. tliis rule it sliould l)c unclt'rst«M)d tliat tlie size of the curb, or

Using

frame, forms

basis fur

tlie

or l)endsoftlie barshoulil

all

bottom of the bar K

where

tlie

curb c

4' at 4',

and the

ri
and that rme of the

mejisuremeiits,

meet the

line of the

curb as shown

in the half section

at the top at 4'.

lines

in Fig. 17K,

meets the

line of the

Therefore when laying

B

K^

10^

i>nhiiliiililil.ii l.iilii.l.iil.i.l.i.Li^1r>>^ 11 10 9 6 7 6 5 -^ 3 2 1

12

Fig.

185.

out the lengths of the bars, they would have to be measured on the line 4 of the l)ar E from 4' to 4" on the patterns, as will be e.xplaineil as we proceed.

The first step is to prepare the triangles from wliich the lengths common and jack bars are ol)taine(l, also the lengths of the hip

of the

After the drawings and j)atterns have been laid out

bars.

full si/e

according to the principles explaineil in Fig. ITS, take a tracing of the triangle in the half section 1) C 4' and place it as shown by A 12 O, in

IM.

Fig. will

Divid.- ()

be 12 inches

IJ,

which

and

(piarter, half-inches,

inches,

the same as on a 2-foot rule, as shown by the figures C) to 12. From these divisu)ns erect lines until they intersect the pitch

.\

which cMm|iletes the triangle •

tbtaiiiing the true lengths of

and conunon bars tracing j»lac«'

it

>>(

as

X

1!

ili<-

anv

for I'

tin*

(

d

X

)

for

jack In similar

size skvliirht.

the

in

shown by H

iM'comes the base nf ba-ic of

a'-o'-

in full size, into

12 ()

diagonal in

Fig.

elevation

1S.'».

triangle for the hip

trI;iiigU> for tlie

connnon and jack

The bar

in

manner take I7s and

Fig.

length 12

O

in a skvlight

i)ars meiusure.s

tlien

whose

12 inches

156

\

SHEET METAL WORK

THE "NASSAUER HAUS Built at the

End

of the Thirteenth Century. Decorated with Coats of Arms.

Ivower Right,

is

" IN

NURNBERG, GERMANY

Railing of Gallery underneath Red-Tiled Roof In the Niche over the Fountain at the a Statue of King Adolf von Nassau.

is

^ii

A i

'^r^.

TERRACE OK HOUSE AT MONTECITO. CALIFORNIA For

IVr
Myrou Hiiiil View of IlulldlDtf.

.11:

Kliiu-r lin-}-, Archltcitx,

Sr
Pasp SOS: niiirniPUt, on I'n^v ^

Lkk

Aut:<'l<^!*'

Klrnt,

and

*-'•''

Src«iuil

Kloor I'lan*

Shown

SIIKKT MinWI. est sitle of

frame)

2

-r-

=-

2

We

feet.

to j)roceeoiiiiiioii

of the

eominon har

d

c

have now the

and hip

tlu-

liar liip

ISo.

Fij;.

jack bars / y are spact**! for 12 inches will e<|ual

Iti

A

i>

leiij^th witli

Imrs.

will l»e e<|iial to twice the

1x4, while the length of the amount of H () in

botl) of

Work

amount

^A

e in V\^. IS*), will l)e

Referrinj; to

Fif;.s.

in Fijj. 1S4,

which are adde
and 4 inches

A

( )

njual

isfi

inches, therefore, the length of ( )

whicli

ThiLS the len^tii in Fij;.

to twice

and Is? the tlie

jack bar

e<|ual to 4° ();

for the full length.

The lengths of the common and hip bars will be .shorter in Fig. 187 because a ventilator has been used, while in Fig. ISO a ridge bar was employe) 1. To obtain the lengths of the common and hip bars in — 4 inches (widtii Fig. 187 use Rule 3: 4S inche.s (length of short side) of inside ventilator) ^ 44 inches; and 44 inches -r- 2 =22 inches or 1 foot 10 inches. Then the length of the conunon bar c' d' mea-sure
O

I80 and

10*0 added

together.

Use the same method where

fraction-

parts of an inch occur. In laying out the patterns according to these measurements use the cuts .shown al

in

Figs. 17S, 179, ISO,

and

ISl, being

careful

measure from thearrowpoints shown on each It

will

be

iKJticed in Fig. 17s

wc always

urc on line 4 in the j)atterns for the

and jack the

bars.

j»rofiles

Tins

K and

F*

is

liij),

done l)ecause the

come

directly

on the

t«»

j)atteni.

mea.s-

connnon, line 4 .slant

in

line

of the triangles which were traced to Figs. 1S4 and \X'>

and from which the true lengths were obtained. a curb might be us«'d, as shown in l*'ig. ISS,

WluTc

TiR. ISS.

which would bring the bottom line of the bar ]\ inches toward the inside of the frame h, all around, then insteaci of using the size «tf 4 x S feet as the basis of measurements deduct .{ inches on each side, nuiking the basis of measuremeiMs .\

7

ft.

'.»

inclies,

and

j)rocee
1H7

."?

ft.

'.•

inches

SHEET METAL WORK

158

ROOFING A good metal covering on

a roof

is

as important as a

There are various materials used

dation.

good foun-

purpose such as terne

for this

The rigid body, or the plate or what is commonly called roofing tin. base of roofing tin, consists of thin sheets of steel (black plates) that are coated with an alloy of tin and lead. AVhere a first-class job is

The soft copper used for and allows itself to be dressed down cap flashing generally well after the base flashing is in position. The cold-rolled or hard copper is used for the roof coverings. In some cases galvanized sheet iron desired soft and cold rolled copper should be used.

is

or

steel

is

employed.

No

matter whether

tin,

employed the method of construction copper be explained as we proceed.

is

is

Another form of roofing

is

known

which consists of black or galvanized strength and stiffness. Roofs having

galvanized iron, or the same, and will

as corrugated iron

roofing,

sheets, corrugated so as to secure

than one-third pitch should as flat-seam roofing, and should be coverless

be covered by what is knowm ed (when tin or copper is used) with sheets 10 x 14 inches in

size rather

than with sheets 14 x 20 inches, because the larger number of seams stiffens

weather.

the surface and prevents the rattling of the tin in stormy Steep roofs should be covered by what is known as standing-

seam roofing made from 14" x 20" tin or from 20" x 28". Before any is placed on a roof the roofer should see that the sheathing beards

metal

are well seasoned, dry and free from knots and nailed close together.

Beforelayingthe tin plate a good building paper, free from acid, should be laid on the sheathing,or the tin plate should be painted on the underside before laying.

buildings.

It is

Corrugated iron

usually laid directly

used for roofs and sides of

is

upon the

purlins in roofs,

and

held in place by means of clips of hoop iron, which encircle the purlins and are riveted to the corrugated iron about 12 inches apart. The method of constructing flat and double-seam roofing, also corrugated iron coverings, will be explained as

we

proceed.

TABLES The

following tables will

prove useful in figuring the quantity of

material required to cover a given

number

188

of square feet.

SIIEtrr

METAL WORK

FL.Vr-.SEA.M

...

Table showing quantity of '

mil

H .

M|uare inches. "

full

^

^

In

tl>e

following

H()<)FI.\'(i

x 20-ineh tin rccjuircil to cover a given »ii»

wit all

l.VJ

Hjofing.

A

8ln-it of II

X

.'

ll

or folilid, 13 X I'j i: ^ iV fractiontil jMirtii of a sheet arc counted a fclgi'
SHEET

160

ISIETAL

WORK

STANDING-SEAM ROOFING Table showing the quantity of 20 X 28-inch tin in boxes, and sheets required to lay any given standing-seam roof. SQ.

FEET

SIIKKT MKTAI.

NKT WKKWIT ]'.<

Trade term

80-lb.

I'KU I

BOX TIN PLATES .'Mil.'

II

»-lb. 90-lb.

DMb.

8B

»

WoUK

lOO-lb.i

ic

j

WelKbt per Sl««

r.f

Im>x.

tl>.

'm

,90

'

lOU

luT

ir.l

SHEET METAL WORK

162

OTHER FORMS OF METAL ROOFING There

is

another form of roofing

gles, pressed in various

known

as metal slates

and shin-

geometrical designs with water-tight lock attach-

ments so that no solder

is required in the roof. 189 shows the laying Fig. general shape of these metal shingles

which are made from tin, galvanized and copper, the dots a a a a

iron,

representing the holes for nailing to the wood sheathing. In Fig. 190, A represents the side lock, showing the first operation in laying the metal slate or shingle nail.

on a

roof,

a representing the

B, in the same

figure,

shows the

metal slate or shingle in position covering the nail b, the valley c of the bottom ^'s- ^8^'

slate allowing

flow over the next lower slate as in

In Fig. 191

is

shown the bottom

A

the water,

if

any, to

in Fig. 189.

slate

A covered by the top slate B,

the ridges a a a keeping the water from backing up. Fig. 192 shows the style of roof on which these shingles are employed, that is, on steep roofs. Note the construction of the ridge Fig. 192,

which

at a a etc., after

is first

roll,

A

and

B

5HEATH/NG

BOAR D

in

nailed in position B are

which the shingles

slipped under the lock

c.

Fig. 193

pl

IJ

shows

jSb SHEATHING BOARD

^^S- 190hip covering which is laid from the of the lower end a the hip having top downward, projection piece for nailing at a, over which the top end of the next piece is inserted, thus

a

roll

% Fig, 191.

covering and concealing the nails.

Fig. 194 represents a perspective

view of a valley with metal slates, showing how the slates A are locked to the fold in the valley B. There are many other forms of

192

RHKI-n^

•netiil

sliiii^'les,

hut

MriWL WORK

163

shapes shown herewitli ure known as

tlie

tlie

Cortright patents.

TOOLS Fig. 195

RI:QI

shows the various hand

er; starting at the left

we have

IRHD

tools re<[ulre«l

hy the metal roof-

the soldering copper, mallet, scraj>er,

A^-,

B ImK. 192.

21 stretch-awl, .shears,

hammer,

tools a notching maciiine

is

aiul dividers.

In addition to these

hand

retpiired for cutting ofT the corners of the

1

sheets, (piired

and

ii;.

r<M)(ing

for e
seam

roofing,

and

r(X)fing

roofing.

]'.»:{.

folders

are

the sheets in

rellat-

and hand double seamer

tongs for standing-seam Tiic roofing doul)le seamer

and s(|ueezing tongs can he

uso»l

ft>r

standing-seam roofing plaiv of the hanil diiiilile seamer), which allow the (in

I'JK.

lai.

operator to .stand in an iipright jM)sition

if

the ri>of

is

not

to«»

steep.

ROOr Mi:\SlR\TI()\ While .some mechanics imdiTsiand tlion»ughly

i03

llie

metltods of

SHEET METAL WORK

164

kinds of roofing, there are some, however, who do laying the various how to figure from architects' or scale drawings the not understand

amount of material required

to cover a given surface in a flat, irregular

The modern house

shaped, or hipped roof.

with

its

gables and va-

Fig. 195.

rious intersecting roofs, forming hips and valleys, render it necessary to on roof measurement. In Figs. 196 to 198 ingive a short chapter clusive are shown respectively the plans with full size measurements for a flat, irregular,and intersected

of the hips

how the length obtained are direct from valleys

hipped roof, showing

and

the architects' scale drawings.

The drawn

a scale as architects' drawings will be, but the measurements on the diagrams are as-

6'0'

tia

sumed, which will clearly show the principles which must be applied when figuring from scale drawings. Assuming that the plans from which

ed i

- A2-0"

—

we

= 3

drawn to a quarter-inch scale, when measurements are taken, every quarter one foot. ^ inch = 6 inches, ^^

are figuring are

then

Fig. 196.

inch

inch represents If the drawings were

inches, etc.

then \ inch = 12 inches, \ inch = I2 inches, etc. yg inch A B C in Fig. 196 represents a scale,

D

as

shown hy ab

was no

shown herewith are not

illustrations

to

12.5

X

flat

6

drawn

to

inches, \ inch

a half-inch

= 3

inches,

roof with a shaft at one side

we will figure it as if there Thus 64 feet X 42 feet = 2,688 square feet. feet = 75 square feet; then 2,688 feet - 75 feet = In a roof of this kind

c d.

air shaft at all.

The shaft is

= 6

194

SHEET METAL WORK 2,613 s
of

fct-t

r»H)lii4i;. ti)

wlikh must

l>e uiitlwl

forming an irreguhir

iH'ing

irreguhir,

roof.

The

ilar to

that useil for Fig. 10<) with the exception

Fig. 197 sluift

is

allowaiife for

=

d

which

Thus

4,S()0 sfjuare is

9.25

To

scpiare feet. sliaft,

x x x

.r

bisect

H C

.\

1)

= lOS

feet

4,aS2.G25

4.')

X-

^ o

O

9^

b

c

xx and

and ohtain a

.r.r

\,s{'A)

.sf|uare feet

The

square

a,

feet,

and

an.l

412

minus 777.'S7o =

X d e t*

9-3

entire roof

—

feet

of surface in Fig. 197.

.'

o

find the area of the irregular

365.375 = 777. M75. -

K

Find the area of h c 39..^ - 3G5.373 or 3(l.^>g

measure the length of a a which is 4S = 412, multiply by 9. Thus 48 X 9 the shafts

^

in

feet. •

^

sim-

is

deterinineil differently to that of the

hcde.

feet

sliape*!

rule for ol)tainuig the area

that the area of the irregular shaft

-}-

iiii

walls at tlie sides. flosliinj; turning up against an
tlie

e

1G3

A 5-0" ^^'K-

1.

1

_1 JC

'•'"•

.shown the plan, front, and side elevations of an in.\ H (' 1 ) tersected hipped roof. represents the j)lan of the main buildIn Fig. 198

is

SIDE

ELEVATION

lie ing intersecte
roof as

if

tlierc

1«»S

We will first figure the main II. F by the wing were no wing attaclml an
<

i

ins

SHEET METAL \WRK

166

up by the intersection of the wing. While it may appear difficult to some to figure the quantities in a hipped roof, it is very simple, if the As the pitch of the roof is equal on four sides the rule is understood. length of the rafter shown from O to N in front elevation represents the true length of the pitch on each side. The length of the building at the eave is 90 feet and the length of the ridge 4S feet. Take 2 = 21. Now either add 21 to the length of the 90 - 48 = 42, and 42 edge or deduct 21 from the length of the eave, which gives 69 feet as shown from S to T. The length of the eave at the end is 42 feet and = 21, as shown from T it runs to an apex at J. Then take 42 feet -^ 2 to U. If desired the hip lines A I, J B and J C can be bisected, obtaining respectively the points S, T, and U, which when measured will be of similar sizes; 69 feet and 21 feet. As the length of the rafter O N is 30 feet, then as follows: 69 X 30 = 2070. 21 X 30 = 630.

^

multiply

Then 630

+

2,070

=

gives 5,400 square

and multiplying by 2

2,700,

feet or

(for opposite sides)

54 squares of roofing for the main building.

From this amount deduct the intersection E L F in the plan as follows: The width of the wing is 24 feet 6 inches and it intersects the main shown

roof as

at

E L F.

Bisect

E L and L F and obtain points W and

V, which when measured will be 12 feet 3 inches or one half of HG, 24 feet 6 inches. The wing intersects the main roof from to F' in the

Y

side elevation, a distance of 18 feet.

Deduct 220.5 from 5400 =

5,179.5.

Then take 18 X 12.25 = The wing measures 33

220.5. feet 6

L

inches at the ridge M, and 21 feet 6 inches at the eave F G, thus =27 feet 6 inches. The length of to making the distance from

V

X

the rafter of the wing is shown in front elevation by P R, and is 18 feet. Then 18 27.5 = 495, and multiplying by 2 (for opposite side), gives

X

995

sq.

ft.

in the wing.

We then have a rooting area of 5,179.5 square

main roof and 995 square feet in the wing, making a total 6,174.5 square feet in the plan shown in Fig. 198. If it is desired to know the quantity of ridge, hips, and valleys feet in the

the following method is used. the plans by adding 48' + 33'6" = 81'

tlie roof,

the hip I until

it

The ridge can be

-

distance I

D in the

On

ply this length

by

4,

which

I'

in the front elevation

the eave line e.xtended, place the

plan as shown from 1° to

D° and draw a line from

D

D° to I* which will be the true

in

taken from

For the true length of

6".

D in the plan, drop a vertical line from

intersects the eave line 1°.

of

in the plan. Multilength of the hip I will give the amount of ridge capping re-

196

SHEET MirrAL WORK This

(luiinl.

«»f

lengtli

ing the vertical

hcij,'ht

liij)

tan also

of the roof 1°

Ik* obtaiiietl

I-

to

For from F'

D in the plan, as shown, D which is the desired length.

Take

tlie

the distanc"e

and draw a

shown hy tlie

line

LF

retjuireil

F L in

from

tlie

from

in the plan.

nund>er of

roof of the wing, right angles to

F which

is

FL

I'^

{)lan

drop a

it ils

this length

tlie

valley

which

will give by 2, This length of valley

by taking the

from

vertical line

shown from F° to L°,

vertical height of tlie

F* in the side elevation,

in tlie plan,

plan by tak-

the true length of

is

feet of valley retpiired.

shown by

tlie

and placing it at P, and draw a lint-

intersects the eave line at F°.

which

Multiply

I to

in tlie plan,

it

plan and j)lace

T^° to F*,

can also be obtaine
to

LF

length of the valley

in the side elevation until

from

in the elevation

I'

right angles to I

from

lo:

and placing

it

at

P

I^ Ut

the desired length similar lo

P, ami draw a line from F' L° in tht; side elevati
ri.AT-SEAM ROOFING

The Fig. 1!>0

step necessary in jjreparing the plates for dat scam notch or cut off the four corners of the plate as shown in

lirst

iHHifing is to

which .shows the plate as

is

it

taken from the

\)ox,

corners a a a a representing the ctjniers which are notchetl on the notching machine or with the shears.

Care mu.st be taken when cutting

oil'

to cut off too

sheets will not edce

little

well,

and not

show

at tlie corners

otherwise

to cut off too

amount

when

tlie

much,

the.se

the shawled

^

^"

corners not

otherwi.se a hole will

the sheets are laid.

To

fiiul

**' proceed us follows: that a l-inch is set the dividers at \ inch ilesireil, .\ssuming e
the correct

where the

to

be cut

lines intersect at a,

off

draw

the line d c at an angle of 45 dt^rees,

which reprasents the true amount and true angle to be cut off on each corner. After all the sheets have been notchetl, they are etlged as shown in Fig. 20(), tlie long sidesof the .sheet being bent right and left, tis shown at a,

while the short

the

sitle

is

bent as .shown at

notched corner aj)pear

lus

at

c.

b,

making

In .some

CJises

after the .sheets are edg«tl the contract retpiires that the 1)«; on the underside before laying. This is usuallv piiintetl d«)ne with a small bru.sh. bring careful that tlic etlges of the .sheets

sheets

SHEET METAL \TORK

168

are not soiled with paint, which would interfere with soldering. Before laying the sheets the roof boards are sometimes covered with an or rosin-sized paoer to prevent the moisture or fumes from below from rusting the tin on the underside. As before mentioned, the same method used for laying tin roofing would be applicable for laying

oil

copper roofing, with the exception that the copper sheets would to be tinned about 1^ inches around the edges of the sheets

have

after they are notched,

and before they are edged.

In Fig. 201 is shown how a tin roof is started and the sheets laid when a gutter is used at the eaves with a fire wall at the side. A repre-

Fig. 201.

sents a galvanized iron gutter with a portion of it lapping on the roof, with a lock at C. In hanging the gutter it is flashed against the fire

wall at J

;

after

which the base flashing

D D is

out on the roof at E, with a lock at F. miters with the flange of the gutter the flange E of the base flashing as

put in position, flashing the base flashing E

Where

B

it is joined as shown at b, allowing shown by the dotted line a. As the

water discharges at G, the sheets are laid in the direction of the arrow H, placing the nails at least G inches apart, always starting to nail at the butt e e, etc. Care should be taken when nailing that the nail heads are well covered flashing

DD

wall as at

by the edges, as shown

J the cap flashing

L

is

O.

198

in

W, by

Over the base

a.

placed, allowing

it

to

go into the

SHKKT MKTAL WOHK Wlifii Ill

Fig. 202

ill l)ii.se

jiiittiiij^

is

shown a

flashtnl into the wall four

and

as

shown

at

I),

two

(lashings tliere are

iiiftluMis eiii|iluve(l.

side thtshiiig hetweeii the roof

A sh«)ws the fhishing turning out on e
mi

ami

j»araj>et

wall.

the nwjf at H, with a lock C, uttach-

courses of hrick al>ove the

where wall hooks and

.

rtxjf line,

-^^

are usetl to paintskins or roofer's cement make a tight joint. Flashings of this be i)ainte
always

underside, and l)etween

slujiild

paper

lie

the

cause the moisture in the wall

This method

rust the tin.

flashing

l>ecause to settle

result

is

is

j)la(ed

brick work and metal, be-

not advisable in

when

the

and when

l)iiil«ling

this

apt to

is

of putting in

is

I'ifi.

new work,

20J.

new, the walls and beams are liable D tears out of the wall, and tlie

occurs the flange

When

walls. disagreeable leaks that stain the

a new roof

is

be placed on an old building where the walls and ctipings are in beams have .settled, there is not so much place and the brick work and

to

danger of leakage. Tlie proper metliod of putting

in flashings

and one which allows

of the metal and the settlement of tlie expansion and contraction which A shows the cap flashings, in is in shown 203, Fig. building for the

When the ma.s4in has coats of paint bcfon* using. painted with two iibovc the roof line the ca|> four of brick to courses wall built his up flashing

.\.

is

j)laced

H

and

in j>osition anil the wall

ct>])ing finislutl;

the

In |>racticc the cap base fhisiiing is cut 7 inches, then bent at right angles through the «t*nter. (lashing making each .side (t and h 'i' inclcs. Tlic l»ase flashing H is then tlipp«-d

is

then

uiuler the cap .slipjx-d

under the cap flashing A

a.N

shown

1110

at

.\.

(\

SHEET METAL WORK

170

Where

the cost

is

not considered and a good job

better to use sheet lead cap flashings in place of tin.

do not

desired,

it is

longer,

and can be dressed down well

rust,

Into the lock

flashings.

is

They last

C

to lay tight onto the base the sheets are attached. After the sheets

down

are laid the seams are flattened

by means

well

of a

heavy mallet,

with slightly convex faces, after which the roof is readv for soldering. When a base flashing P"b

required on a roof which abuts against a wall composed of clap boards or shingles as shown

is

in Fig. 204, then, after the last course of tin Fig. 205.

j^g^g

locked into the course

before

laid, the flashing

B

with the lock a

A is

and extends the required distance under the

The

boards D.

how

A

been

it is

flashing should always be painted and allowed to dry placed in position. In the previous figures it was shown

the sheets are edged, both sides being edged right and

left.

In

Fig 205 is shown what is known as a valley sheet, where the short sides are

edged both one way, as

shown at a a, and the long sides right and left as shown at bb. Sheets of this kind are used

when

the water runs together from two Fig. 206. directions as shown by in Fig. 206. By having the locks a and a turned one way the roof

A

is

laid in

both directions. Fig. 207

the flashing

shows a part plan of a roof and chimney A, around which is to be placed, and explains how the corners C and D are double seamed,

B CDE

whether

on a chimney, bulkhead, or any other object on a roof when the water flows in the direction of the arrow F.

Thus

it

In laying ance must be it.

The

first

operation is shown at a and Fig. 207. the final operation at b. will be seen that the water flows past the seam and not against flat

seam roofing

made

for the

especially when copper is used, allowexpansion and contraction of the sheets.

200

MKTAL WOUK

SIIERT Care should ill

\V.

Fi},'.

r
l)c

taken not to nail Wliilf this

201.

on a g«H)d joh, as

I) in Fij;. 2()S

should he

wt-ll

The

the sheet as

«lirectly tlir«>Uf,'h

is

shown

method is j^eneraliy employed in tin as on c«j[)|)er nx)ling, cleats as shown at

tised.

To show how sheets.

171

they are used, lock tm the cleat

and nailed into the roof boards

A and H

D

is

at

ii

represent two locked-etlged of tlie sheets e
locke
b c

and

d, ar as

often as retjuired.

d

b

1^ B D

Fig. 2(is.

In this

maimer

the entire njuf can he fastene
for expansion havin«; a nail driven into tlie sheets, thereby allowing and contraction of the metal. The closer these cleats are placed, tlie

firmer the roof will be

and the better the seams

fewer cleats, time

be .saved

is

lost

when

may

will hold.

in laying the rt)of,

By using but double this time

soldering the seams, for the heat of the soUiering copper

Imk.

JO".).

causing a succession of buckles, which retard When the seams are 10 [)er cent more .solder. .S4>ldering re<(uire luiiled or cleaite
ami

with ease and less

When

soliler.

a connci-tion

terra cotta, the

is

to

method .shown

be made between metal and stone or in

Fig. 2(K)

is

tration .shows a stone or terracotta cornice A.

201

employnl.

The heavy

This line

illus

ah c d

SHEET METAL WORK

172

represents the gutter lining, which is usually made from 20-oz. coldis of stone, the stone cutter cuts a If the cornice rolled copper.

A

A

as at B, dove-tail in shape, after raggle into the top of the cornice which the lining abcdis put in position as shown. Then, being careful that there is

poured

no water or moisture

into the raggle

and

after

in the raggle

cooled

it is

the caulking chisel and hammer. By having the dove-tail cut, the lead

it is

is

B, molten lead is down well with

dressed

secured firmly in position,

holding down the edge of the lining and making a tight joint. Should the cornice be of terra cotta this raggle is cut into the clay before it is

baked

This method of making connection between

in the ovens.

Fig. 210.

metal and stone is the same no matter whether a gutter or upright wall WTien a flashing between a stone wall and roof is to is to be flashed.

be

made tight,

in

molds made

then instead of using molten lead, cakes of lead are cast for this purpose, about 12 inches long, and these are

driven into the raggle

B

as

The most important

shown is

shown

soldering copper employed pounds to the pair. WTien rosin in tinning the coppers,

209 at X.

in Fig.

step in roofing

is

is

the soldering.

used as a

but when acid

is

The style of

210 and weighs at

in Fig.

flux, it is also

used as a flux

least

8

employed

for soldering

zmc

or galvanized iron, salammoniac is used for tinning the coppers. It will be noticed that the soldering coppers are forged square at the ends,

and have a groove

at A. When the copper turned upward the groove should be filed toward the lower side within J inch from

filed in

one side as shown

is

^*g- 211-

the corner, so that

when

upon the seam,

shown

as

the groove

is

in Fig. 211,

placed it

acts

as a guide to

the copper as the latter is drawn along the seam. The groove a being in the position shown, the largest heated surface b rests directly on the seam, "soaking" it

thoroughly with solder.

the locks, about 6

pounds

tin roof is to

As the heat draws the solder between and h solder are required for 100 square

x 20-inch

tin

be avoided

fta

feet of surface using 14

seams in a

of ^

202

The acid

u^e of acid in soldering contact with the foming

m

Ml.

-

COCYAftC'lTC^

r i'

Kj

1 t

z.

- '\^«i

r.*^

^.-.-r-f'iT

PLANS OK MODSF. AT MONTECITO. Myri>ii

Hunt K

(

Al.IFORNIA

Kliiior (>r«}'. AroUII
i

MKTAI.

SlIKI-rr

lijire

and corners, where

ed^'es

cause rusting. rosin shotild he employe*!.

jjetlier,

will

WOUK

tlie slieeLs

are

173

fol«le
No other soldering Hux The sune flux (rosin)

ami seametl

t«>-

but go«jd clean sliould l>e use
when soldering copper n^ofing whose edges have previously been tinned with rosin.

We will now consider the soldering of upright seams. The solderas shown in Fig. ing copjier to l>e emj)love«l for this purj)ose is shaj>ee,

3Fig. 212.

thick at the end, and is tinned on one side and the end only; if tinned othersvise, tlie .solder, instead of remaining on the tinned side when

would flow downward; hy having the soldering copper tiniie
t

)

A

soldered by first tacking the seam to then tlioroughly soaking the .seam, the .sheet

an
In

it

lay close,

to strengthen

it

the soldering copper it in the position

using

should shown

make

of solder placing ridges the same.

tlien

across

1", is

be held

l)y

)-

C, wliidi allows the sol-

y"

^

./

der to flow forward and into the

seam, while

if

the c-opper were held

/ '^^^D

shown by D, the solder would flow backward and away from the

a.s

seam. solder

In ".soaking" the .seam with copper should be place
directly over

the

heated and draws

where

vl\(^'

Vifi.

213.

tlie

The

lapj)eil

part, so

tlie .solder

that

between the

this cross joint o<curs; the

riM.f

the metal gets tlioroughly joint.

It

same methods

makes no

dilTer-

are usctl.

being comj)leteil, the rosin is si-rajHtl oiT the .seams ami and painted with good iron oxide aiitl linseetl oil paint.

tlier(M)f cleaiie
.Some roofers omit the s<Ti[)ing of rosin nnd paint dirwtly over it. If the is the cau.se «)f rusting of se^uns which sometimes occurs.

Tliia

20fl

SHEET METAL WORK

174

paint is api)licd to the rosin, the hitter, with time, will crack, and the rain will soak under the cracked rosin to the tin surface. Even when is dry, by raising the cracked rosin, moisture be found inulerneath, which naturally tends to rust the plate more and more with each storm. If the rosin is removed, the entire

the surface of the roof will often

tin surface is proteeted

One

of the

most

ing a conical tower.

by

paint.

jobs in flat-seams roofing is that of coverthe roof in question is round in plan and taper-

difficult

As

ing in elevation,

method

is

it

necessary to

know

the

of cutting the various patterns for the

ABC

In Fig. 214 shows the elevation of a tower to be covered with flat seam sheets.

roofing, using 10

X

14-inch tin at the base.

As-

suming that the tower through B C is 10 feet 6 inches, or 120 inches, in diameter, the circumference

3.141G inches.

is

obtained

by multiplying 120 by equals 395.8410, or say 390 10 x 14-inch plate is to be used at

which

As

the base of the tower the nearest width which

can be employed, and which

will

divide the

space into equal spaces, is 13^ inches without edges, thus dividing the circumference in 30 equal spaces. This width of 13^ inches together with the length of the rafter A B or B C in elevation, will

be the basis from which

patterns for the various courses will

all

the

be laid

off.

At any convenient place in the shop or at the building, stretch a piece of tar felting of the required length, tacking it at the four corners with nails to keep tlie paper from moving. Upon the center of the felting strike Fig. 214.

A B in Fig. A B or A C in

a chalk line as of the rafter

Fig. 215 at either side,

making it equal to the length At right angles to A B in draw the lines B D and B C each equal to Of 215,

Fig. 214.

one half of the 13|^ above referred to. From the points draw lines to the apex A (shown broken). As the widtli of the sheet used is 10 inches and as we assume an edge of f inch for each side, thus leaving 9j inches, measure on the vertical line A B inches, being

C and

D

lengths of 9| inches in succession, until the apex

204

A is reached,

leaving

wohk

siiKirr MF;r\i.

the

liist

slut't at

A

(ilttaiiinl oil

ami lie

A

top to ••miu- a.s it may. tiraw liiu-s |»arallfl to (' 1)

l) JUS shtiwii.

the net

'I'limu^li tlie |M>iiiLs

tlii'

I?

i)atterii.s

'I'heii

the variiiis

for siniilarlv

.^lla|M•s

marketl

iminhered

jtatterns

on the

felting

I

2

.'{

A

<"

etc. will

A

'

'I'ake the shears

courses.

tliiis

the hues

iiitrr statin;;

and cut out the

and nuuiher them

a.s

re(|uiretl.

No.

For example, take the j)aj)er pattern 1, place it on a sheet of tin a.s shown in

I'ig. 21t),

and allow g-ineh edges all arounil, .\ B (' and D. Mark

and notch the corners on

tlie tin pattern "No. 1, 21> more", as 'AO sheets are re(julre«l to go arouixl the tower, and cut 29 more for course No. 1. Treat

of the paper patterns from No. 1 to tiie apex in similar maimer. Of course where all

the patterns become smaller in size at the top, the waste from other patterns can he used. In Fig.

217

is

.shown

how

the sheets

should he edged, always being careful to have the narrow siile towards the top with the edge toward the outside, the flat

seam

roofing.

Lay

same

as in

the sheets in

tlie

u.sual

manner, breaking joints as in general As the seams are not sohlered |)ractice. care must be taken to lock the edges well. .\fter the entire roof is laid and before closing the seams with the nudlet

take u snuill brush an
C

-

>

tin'

locks with thi«-k

lead,

with

the

will

make

job.

then

mallet.

.\fter

close

This

a water-tight

the

r(M)f

is

SHEET METAL WORK

176

terns the line

as

from

C

to

D

and

all

following lines should be curved,

struck with a radius from the center A, and not straight as shown. those the wi-iter would say that the curve would be so little on a

if

To

small pattern, where the radius

is

so long, that a straight line answers

the purpose just as well in all practical work; for it would amount to considerable labor to turn edges on the curved cut of the sheet, and there is certainly no necessity for it.

WTien

be connected together, as for instance or copper flashing, copper tubes to galvanized iron gutin or zinc connection with copper linings, care must be ters, flashings different metals are to

tin roofing to

taken to have the copper sheets thoroughly tinned on both sides where it joins to the galvanized iron, zinc, or other metal, to avoid any electrolysis

between the two metals.

It is

a fact not well

known

to roofers

we take

a glass jar and fill it with water and place it in separateof zinc and the other of copper, and connect the two clean ly, strips, one

that

if

two with a thin copper wire, an

electrical action is the result,

and

if

the

connection remains for a long time (as the action is very faint) the zinc

would be destroyed, because,

may

it

he said, the zinc furnishes the fuel the electrical action, the

for

as

wood

fire.

same

furnishes the fuel for the

Therefore,

if

the copper

was

not tinned, before locking into the other metal, and the joint became

wet with

rain, the coating

of the

metal would be destroyed by the electrical action

between the two metals, and the iron would rust

through. Wliile the roofer roofing

is

seldom called upon to lay out patterns

work occasion may

arise that a roof flashing

is

for

any

required around

a pipe passing through a roof of any pitch, as shown in Fig. 218, in which A represents a smoke or vent pipe passing through the roof B B, If the roof B B were the metal roof flashing being indicated by C C. level the

opening to be cut into the flashing C same diameter as the pipe A.

C would

simply be a

But where the roof in becomes an the the flashing ellipse, whose minor pitches opening axis is the same as the diameter of the pipe, and whose major axis is true circle the

ao6

^'TTFF'I'

lo

ttjiial taii)e«l

will

pitch a

till'

tlie

by

use of

In

h.

few

ji

MKTAL WoUK

I'ig. L'l'J

nails, a

1~7

slmwii liow Uiis

i.s

ami a

strinir.

pencil,

()l>i>|>c>nin^ is

which the

rfM)fer

always have handy.

A W representing the >lant of the roof, and the pipe of the
First tlraw the line

make

then

[iroper

H

line

."^

'

.shown.

where tlie

draw the center

Xe.xt

line.

of

the

all

t

line

this

r«>of

line,

A

B.

and the and

F.

and

(J

K

making

estal>-

Having

j)ipc.

K L

lished the minor axis

O

and the major axis the ellipse

ing

1

II,

made by

is

III-

major and with '

as a center strike arcs in-

tersecting the

major

each of these two

keeping Nt>te

tained. th«'n

jM)ints

the string

ill

placnl string,

axis, at iM)ints

K M

the dotted lines

a,

II.

tak-

half the

axis, as a radius,

L

H.

each

the half diameter

to

cipial

of the

and

.\

L

1

F

draw

at right angles tn I

<"

II r«'I

Through

spectively.

KL

i

intersects

I,

points where 1) intersect

pipe, as po n t

h e

h,

it

taut

how

X.

in sui-h a

will

it

all

Drive a small nail

when

way

that

K.

Move

a

in

shown by

.string to the nails as

|K)int

j)encil

i>

the |)cncil aK)ng the

the tinu' imtil the ellipse

K

the position of the string changes

\\IHN(i-Sr:AM kOOl

Another form of mclal is

reach

ami N.

-'•'

L

II

when

(i it

is

ol>-

reache."

etc.

SI

which

M

and attach a

'*^-

u.s«'
rooliiig is that

on steep nnifs not

of the building.

It

known

than

consists of metal sheets

s<'am.s are |o<'k«'d a> in (hit

.standing Icx-keil

less

seams, as

M-am will

nwiling,

\

as standing seiun.

pitch, or

whose

and who.se

be dcscrilxtl

•zoi

l\(i

\

cni.-vs tir

the withh hori/jontal

vertical s«>ams are

in conne«-tion

with Figs.

SHEET METAL WORK

178

220

220,

Assume

229 inclusive.

to

making

that 14 x 20-inch sheets are used

and

A

on the 20-inch

sides only, as shown in Fig. by the sheet 13 x 20 inches. After the required number of

the sheets are edged

sheets have been edged,

and assuming that the length roof

is

30

feet,

then as

of the pitched

many

sheets are

locked together as will be required, and the seams are closed with the mallet

and soldered.

In practice these strips are prepared of the required length in the shop, painted on the underside, and when

dry are rolled up and sent to the building. If desired they can be laid out at the build-

Fig. 220.

ing,

which avoids the buckling caused by

from the shop

rolling

and transportation

to the job.

After the necessary strips have been prepared they are bent up with the roofing tongs, or, what is better and quicker, the roofing edger for standing-seam roofing. Tliis is a machine into which the strips of tin are

fed, being dis-

charged in the required bent form shown at A or

B

in Fig. 221,

bent up

1

inch on one side and IJ inches on the other side.

Or

the machine

desired,

^'^- ^'^^^

will, if

bend up \\ inches and \\

inches, giving a |-inch finished

doubled seam in the first case and a 1-inch seam in the second. WHien laying standing-seam roofing, in no case should any nails be driven into the sheets.

This applies

nized iron sheets. I"

J

to tin,

A cleat should

copper or galvabe used, as shown

which also shows the full size for laying the sheets given in Fig. 221. Thus it will be seen in Fig. 222 that \ inch has been added over the measurein Fig. 222,

-k

^XCLEATN

ments

in Fig. 221, thus allowing edges.

These

cleats

shown

in Fig.

222 are

made from

Fig. 222.

scrap metal; they allow for the expansion and contraction of the roofing and are used in practice as shown in Fig. 223, which represents the first operation in laying a standing-seam roof,

and

in

which

A represents

the gutter with a lock attached at B.

208

The

MKTAL WORK

SIIKET

j;imii

lock

arc

la.^itncti

Ihim;^'

li

in

in flat

follows:

Take

laiti

its

hv means of cleats unrler the

|)Ositinn

— the same as

170

.scam nxdiiig

the strip

('

— the

stamiiri;; y^aiu

ami lock

it

.stri|»s

well into the

A its shown, ami place the cleat sliown in Fig. the upright lientl of the strip C in Fig. 2'2.'i a^ shown tijijhtly a},'ainst at 1), anti fasten it to the roof by means of a 1-inch roofing nail a. lock

H

«)f

the "gutter

222

Fig. 223.

Press the strip C firmly onto the roof and turn over e
holds

it

down and

K

against the cleat 1) and turn over the e
in jKJsition.

Fig.

Fig. 225.

-JJ-I.

and by using them it will be sitMi that no nails have Ikhmi driven through the .sheets, the entire roof being held in positi«)n by nieans cf

aj)art

the cleats onlv.

The

.second operation

hantl ilouble si-amer .s<juee/.ing tongs,

and

is

and mallet

.shown (>r

the single .seam

in

Fig. 22

By means

I.

of the

w itii the roofing double .seamers and is

made

as

shown

at «.

The

third

.shown in Fig. 22') where by the n.se «)f tlte .same In Fig. '2'2^) is .shown how the tools the doubled seam a is obtained. last

finish is

operation

made

is

with a ctimb ridge at

tin*

(oj).

The

.sheets

A A A have

SHEET METAL WORK

180

single edge as shown, while the opposite side B has a double edge turned over as shown at a. Then, standing seams hhh

on the one side the are soldered

down

In Fig. 227

is

to

e.

shown how the

side of a wall

is

flashed

and counter

Fig. 226.

A

flashed.

and

C

shows the

gutter,

B

the leader or rain water conductor,

the lock on the gutter A, fastened to the roof boards by cleats

Fig. 227. 9-s

shown

D. TJie back of the gutter is flashed up against the wall shown b^ the dotted line E. F represents a standing-seam locked into the gutter at H and flashed up against the wall as high at

as high as strip

310

SHEET METAL WORK xs at

shown by

J J.

tlic ilotteil line

.Vs

the Ha-sliing J J

part to the wall the l>eain.s or wall

any

can

ISl

E

Ls

not fastenetJ

settle witliout tlLsturhing

counter or cap Hashing K K K is now slep{>e<J as heavy lines, the joints of the brick work iK'ing cut out to This is well fastenetl with allow a one-inch flange d d d etc. to enter.

The

the tliushing.

Jiown by

tiie

flashing hooks, as indicatetl

by the small dots, and then made water-

tight w ith roofer's cement. As will be seen the base flashing a tlistance indicated by J .1 and

L L;

covers to

the corner

is

cajj flashing

overlaps the

double seamed at

M

shows a sectional view through the gutter showing liow the tubes ami leatlers are a

b.

The

joined. at

i

()

is

X

tube

and soldered

i,

is

flanged out as

shown

to the gutter; the leader

then slijjped over the tube

N

as shown,

and fastened. In the section on Flat-.^cam Roofing

it

was explained how a conical tower, Fig. 211, would be covered. It will be shown now

how

this

tower would be covered with stand-

ing-seam roofing. As the circumference of tlie tower at the base is 396 inches, and

assuming that be

1-1

x 20-inch

base of

use«l at the

tlie

tin

tower,

))late tlie

is

to

nearest

be employetl and which base intoe<^{ual spaces is 17 ^''^ inches, witliout edges, thus divitling the cirwidth which can

will divide the

cumference into 23 equal parts. Then the width of ITn'j inches and the length of the

AH

rafter

AC

or

basis from which for the

standing .seam

cee«l

follows:

JLs

H

be the

in elevation will to construct strip,

for

^

the pattern

which pro-

'

1) ill Fig. 22.S represent a 2()-inch wide strip l.icktNl and the n-cpiirnl length. Through the center of ilie strij) draw Now measure the length of the rafter .\ \\ or .V (' in Fig. the line 1'. F. 211 and place it on the line V. V in Fig. 22S its .shown from II to F. At

T,ct .\

(

soldj-retl to

right angles to 11 e<|ual

to

S\\

F on

in»'hc.s,

eitluT side

draw F

O

being one half of the

21

1

and F

\.

making each

ITj'j alH)ve ref»Trc«l to.

SHEE'l

182

METAL \WRK

O draw lines to the apex H (shown broken). At and H O draw lines H P equal to 1^ inches and H S equal to 1 j inches respectively. In similar manner draw L D and O C and connect by lines the points P D and S C. Then will P S C D From

points

L

right angles to

and

HL

be the pattern for the standing seam required.

When

strip, of

which 22 more

will

be

the strips are all cut out, use the roofing tongs and bend up the sides, after which they are laid on the tower, fastened with cleats, and double seamed with the hand seamer and mallet in the usual manner. If the

tower was done

nized sheet iron or

could be used, as

steel,

many

m copper or

galva-

where 8-foot sheets

sheets

would be

cross-

locked together as required; then metal could be saved, and waste avoided, by cutting the sheets as

shown

in Fig.

229 in which

AB CD

shows the sheets of metal locked together^ and E and F tlie pattern sheets, the only waste be-

Where ing that shown by the shaded portion. in Fig. 214 sets over the tower, the the finial

D

'^'

""

standing seams are turned over flat as much as is required to receive the finial, or small

notches would be cut into the base of the

finial, to

allow

it

to slip over

Before closing the seams, they are painted with the standing seams. white lead with a tool brush, then clos.ed up tight, which makes a good tight job.

CORRUGATED IRON ROOFING AND SIDING Corrugated iron

is

used for roofs and sides of buildings.

It is

upon the purlins in roofs constructed as shown in and the former being constructed to receive sidings of 230 231, Figs. in while the latter figure the side walls of the building iron, corrugated usually laid directly

Special care must be taken that the projecting edges of the iron at the eaves and gable ends of the roof are well secured, corrugated are brick.

otherwise the wind will loosen the sheets and fold them up. The corrugations are made of various sizes such as 5-inch, 25-inch, IJ-inch |-inch, the measurements always being from A to B in Fig. 232, and the depth being shown by C. The smaller corrugations give a

and

313

SUKKT MKIAI. WoUK

IS3

sillier and pleasing ;i|)|K'aran(i*, Imt llie lurjier rurriij(ation.s are to |je further the a ^eacer jmrliiis tli.staiict'.thfreljy juTjiiittiiij,' span

luuri'

will

apart.

J

I'ig.

The

230.

of the metal f;ene'-ally iise
/

i-r

SHEET IMETAL WORK

184

TABLES The mation

following tables will prove of value

to

when

desiring

any

infor-

which they appertain.

MEASUREMENTS OF CORRUGATED SHEETS Dimensions of Sheets and Corrugations.

RESULTS OF TEST of a corrugated sheet No. 20, 2 feet wide, 6 feet long

uniformly with

Load

fare clay.

between supports, loaded

;tif.i-:t

The

is follitwiiij!; talilf

ct)rruj;aliiig.

j:?

"1.1 I

M.'.

23 St

W

.018

.73

mi"'''\'

tul
wmrk sUwts

.{(1^

w* iinlifs wi«Je lK-fi>re

SHEET METAL WORK

186

A

Should the gable have a fire wall, then let the sheets butt against the wall and flash with corrugated flashing as shown in Fig. 235, over which the regular cap or counter flashing is placed as explained in connection with Fi";. ^ 227. Should

^^—.^^ _

B

the

\^__

ridge of

the roof

against a wall, as

\^/y/yyyjmi^m\\\w///m'Mm^

ROOF LINE

shown

A at

butt

B

in

Fig. 230, then an end-wall flash-

ing

is

used as

shown

is

in Fig.

236 which must also be capped, either using

by

cap flashing or

allowing the corrugated siding to overlap this end-wall flashing

Fig. 235.

Fig. 234.

as would

be the case at

B

in

230.

Fig.

Now commence

the

second course at the eaves, giving one and one half corrugations for side lap, being careful that the side corrugations center each other exactly

and

nail with

washers as shown in Fig. 237.

Nail at every other corrugation at end laps, and at about every 6 inches at side laps, nailing through top

of Fig. 236.

this

manner

corrugation

Fig. 237.

as

shown

Continue laying

in

in

until the roof is covered.

The same

and flashing if the corrugated iron were to be fastened to iron purlins, and the method of fastening to the iron frames would be accomplished as shown in Figs. rule

is

238 to 240 inclusive.

to

be observed

in regard to laps

Assuming that

steel structures

are to be covered, as

shown

230 and 231, then

A

in Figs.

in Fig.

238 be the iron

let

rafter,

Fig. 237.

B

D

the cross angles on which the sheets of the clip or clamp C, which is made from

are laid, then by means hoop iron and bent around

angle B, the sheets are riveted in position. In Fig. 239 is shown another form of clamp, which is bent over the bottom of the angle iron.

tlie

216

;HKF.T MK'IAI.

blieet

B

\S1

slu)\vs still iiiiotliiT iiietli<Ml, wlierc the claiiii)

240

Fig.

WOHK

at K,

unminl the angle A at D. between tlie corrugated opening

the storm drive in rugatetl

F is riveted

tlieii tiiniitl

wood

used a^ shown

filler is

in Fig. '2\\.

'!'»•

uvriiil

to the

having

at the caves, cor-

'I'his

keeps out the

^

V

I FiR. 239.

Fig. 2:W.

snow and

On imn

sleet.

framing

this

Another form of corrugated iron roofing put

is

is

made

shown

of pressed metal.

This

in Fig. 242.

is

with cleats in a manner similar to standing-seam r(X)fing. tliere are hips on the roof, the corrugated iron should l)e care-

down If

and the hip This lead.

fully

cut

with

sheet

c«)vered is

hest

done by having a wooden cove or

place

filler

again.st

which

Sheet lead this

is

wooden

<1

tlie

tlien

on the

formed over

and

core

and

hip,

roofing butts.

into

the Fir. 210.

ta.stcne
by corrugations, meJMis of wood screws through the lead cap can

be

worked

the W(Kiden core.

intt»

into

any desireatsof paint

'i'he

lead

soft,

it

When

before laying, and

from

it

sheets, i

'*' "

n

Fit

lientling

ch

<-s

it

in

corrugated iron to lit the re(|uired angh-. corrugated iroti over the vallev from (I to s in(•lle^. cut

tlu-

When

a

make

wide

24-intii

u

jt

on each

1

2

.si«le.

the valley, an«l

Then

lap

tlie

chinmey is to Im- flashnl, a.s shown in Fig. 244, use plain and flashing into the chimney joint>, and allowing

iron, ix-nding U|)

217

SHEET METAL WORK

188

the flashing to turn up under the corrugated iron at the top about 12 inches and over the corrugated iron at the bottom about the same distance. At the side the flashing should have the shape of the cor-

rugated iron and receive a lap of about 8 inches, the entire flashing

Fig. 242.

being well bedded in roofer's cement. \Vlien a water-tight joint is required around a smoke stack, as shown in Fig. 245, the corrugated iron is first cut out as shown, then a flashing built around one half the

upper part of the stack

to

keep the water from entering

This

inside.

best done by using heavy sheet lead and riveting it to is

the sheets, using strips of sima r corrugated iron as a

i 1

washer to avoid damaging the lead.

Before

riveting,

the

flashing must be well bedded in roofer's cement and then

make a beveled angle of cement to make a good joint. After this upright flashing is is set over

in position a collar

the

Fig. 243.

bolted

and made

tight as

shown.

same and fastened

to the

stack by means of an iron ring Cement is used to make a water-

This construction gives room tight joint arovmd the stack. stack to sway and allows the lieat to escape.

Sometimes the end-wall flashing shown

218

in Fig.

for the

236 can be used

FRONT AND REAR VIEWS OF RESIDENCE OF MRS. H. M. COBB, MAGNOLIA DRIVE, CLEVELAND, OHIO Watterson & Schneider, Architects, Cleveland, Ohio.

FRONT AM) KKAK \11.WS OK HKMKKNU. I

Wnitprooti Cr," i>-

•

»3Rnno.

Flmt

Siorjr

A

^l^

I.KVKI.ANI).

MH.

M.

1.

llHlMls,

Srhnrlilpr. An-hliwin, t'lcvplaiiil.

WulU

i.mi.i,

t>l>li«.

of MrCatmlnnil nrlok. %\cnW o'

('oliibltinlloii

.MAi.Sviii\

OHIO

KnlTllr

AVir..n.

QUo. Koofl

vf

SHEET MEIWL WoKK to goo«l a
the currugatetl iron

Imiltliiiji; tlie ui>riglit

inet't.->

1S^»

llasliing in Fi;^. 24'j.

at the ridge, as at 1)

and

Where

i) in Figs. 2'.U)

and

^p-p_^-_

Fig. 244.

^\, a wooden

core

tlie hij)

and an angle

ridge,

is

plac^I in position

TiK.

corriigatnl iron,

a ridge

roll

i.s

is

a.s

exphiined in connection

ridge, pressed

phiced over the

witli

by dealers who furnish the

21.".

riilge

jis

.sh(»wn in Fig.

re«jwiri-d, the .shape .shown in Fig. '217

210

'2\i\.

is

When

eniployitl.

SHEET METAL WORK

190

These ridges are fastened

direct to the roof sheets

by means of riveting

or bolting.

LAYING CORRUGATED

SI

DING

Before pntting on any corrugated siding or cla])boarding, as in Fig. 24S, a finish is usually made at the eaves by means of a

shown

Fig. 24G.

hanging gutter or a plain cornice, shown in Fig. 249, which is fastened This method is generally to the projecting wooden or iron rafters. used on elevators, mills, factories, barns,

etc.,

where corrugated

crimped iron or clapboards are used for either roofing or siding.

iron,

This

Fig. 217.

and gable projections, so as to make When laying the siding commence the building entirely ironclad. at the left hand corner, laying the courses from ba.se to cornice, giving style of cornice covers the eaves

the sheets a lap of two inches as the ends and one and one half corruga-

Fig. 248.

Nail side laps every 6 inches and end laps at every tions at the sides. other corrugation, driving the nails as shower in Fig. 250.

Where

the sheets must be fastened to iron framing use the

same

method as explained in connection with Figs. 238, 239 and 240. In If siding this case, instead of nailing the sheets, they would be riveted. the studput on the wooden studiling care should be taken to space In of iron used. width the ding the same distance apart as the laying

is

220

siii:i:r

vase piet-es of

tliis

eml of

tlie

facli

stiidiliti;;

miim.

sIhmiM

In-

i'.»i

plat «i| Ix'twdMi the iipri^liLs at

nail tlir laps.

.slu-rt (u

\\<)1:k'

\\ lini toveriiig gruiii cievutur"*

(\)nuneinr at the hase and necessary to use swinging scall'olds. ( 'omineiKe of the course to the the the scatt'ol.!. eave, leii<,'tli carry up it is

and

at tlie left luiiid

j^ive

and a two-inch lap

the sheets a lap of one coriui^ation on the side

at the end.

Nail or rivet in every corrugation 'i inches from the lower

end of

Fig.

allows

sheet; this

tlio

for settling of the huilding.

When any lie

(ii\frfd

oil

two

(ir

iron

are

A to

is

nior«'

made

corner casinjjs

.sides, flat

structure

-d.

I(

that a ralihet .sides

(I

an
of

eniploved, of a

sha|<e similar to that .shown

H, I'V-

i^

h

he

s.eii

heiit

on

lH>th

to

admit

edges of tlie .siding. casings a jamli is usnl as shown at

frame.

II

to re«'eive the siding,

In

I'ig.

J.'iL*

is

KiK

the

rough l.el

-diy

iit

will

This makes a neat

.siding.

2.")«.

on

finish

a

If

at .\,

and a

-'.''

I.

outside and

tlu*

window opening

l-'ig. 'J.'»l

,

is

hides to

whirh has a similar

sipiare heiid at

l>

t«»

ral>-

nail against the

.shown the ning.

091

the

have

It is

SHEET METAL WORK

192

bent so that a

nailed to the

is

window

or other frame at the bottom,

while b forms a flashing over which the siding will set. Fig. 253 shows the sill of a window, which has a rabbet at a, in which the siding is

Fig. 253.

Fig. 252.

slipped ; then b forms a drip,

and any water coming over the

over the siding without danger of leaks; window frame.

c is

awnings.

which corrugated iron Sheets laid on wood are nailed

sheets laid

on angle

Another use

to

sill passes nailed in white lead to the

is

put

is

to cover

sheds and

in the usual manner, while

iron construction are fastened as explained in the

Fig. 254.

In Fig. 254 is shown an awning over a store laid iron In work of this kind, to make a neat appearon angle supports. are cui'ved to conform to the iron bracket A. sheets the ance, preceding sections.

222

CORNICE OVER BRICK BAY * An ^ides of

elevation and plan of a brick.

which are S inches, 3

lj;iy

feet 2 inches

are .shown in the illu.stration, tho

and

feet

Ft

10 inches wide.

I^ijm

allowed on the 3 feet 2 inch pieces and no laps on the S inch and 5 feet 10 inch i)ieces. The lookouts or iron braces are indior flanges for soldering are to

\)e

cated in the plan by the hea^•y dashes making a total of 9 required. After the detail ."section is drawn and knowing the angle of the bay in plan, the angle

is

placed as

vertically from

.'i—1

shown by ABC, being careful The miter line

BI), the section divided into equal spaces,

miter line

drawn

as

BD

At

as shown.

shown by

similar figures from

drawn from the miter

line

Now

BD

and

right angles to

angles to 1-2G, lines are dra\\'n

miter cut shown.

to place

in the .•section.

and

1

Ls

vertical lines

BC

intersected

drawn

dropped

to the Ls

which points at right

by similar numbered

lines

BC, thus obtaining the upjwr

using this miter cut in practice,

from either points 25 or 24 (which rcpre.sents the 8 inches, 3 feet 2 inches and 5 feet 10 inches.

a line

the girth of the section

to 2G, through

at right angles to

CB on

then drawn as shown by

The

make

the distance

line of the wall) equal to

3 feet 2 inches

and 5

feet

10 inches have oppo^ite miter cut^ as shown.

As right

will

be seen by the plan, two eight inch j)ifces will be required, one Nine left and two 3 feet 2 inch and one 5 feet 10 inch pieces.

and one

iron lookouts will be required

where holes are punched * 1

formed to the shape shown

in the detail section*

for bolting as there indicated.

nv illuatrutlon rcfemxl to will

l>o

(ouud oa

823

tlie

buck of

tliiii

imgv.

\\\\\\\v.y\\\\\\\\\v

w a, -r*

C


" W o

^

."

-t^

-^

cu

o

to

^ 3 O

o w < n H H

>K

_ -

(fl

«

s H

in

n o «

(0

a-

a H to

O 2 O Hi*

J 6<

H ee

o

7 ©-^ .,-2-.e-

:,oi-s^-

SHEET METAL I'AHT

II

WORK

COIi^MCi: There

is u»)

trade

iti

WOPK

the liuildiii^ line

ti)-
wiiieh Iia^ ina«le

.-.uch

Sheetrapid projjress as that of Sheet-Metal (Joniice, or Arehitectural Metal Work. It is iKit very lun^ since the j^eiieral scope of this braneh iif

(Taftsinaiishij)

merely represented a tin-shop hnsiness on a larj^e Fn)iu an enlarged this is changt^l. tt)-tlay,

But as things are

seale.

that title tin-shop business, sheet-metal cornice work, including under everA' branch of architectural sheet-metal work, has l)ecoit'e one of tlie

substantial industiies of the countrA-,

anv

mechanical branch

<»ther

comparing favorably with almost

Nor

in the building tra«les.

is

this

wrk

In tlie smaller towns is .>.hown the progconfined lo the larger cities. ress of architectural sheet-metal work in the erection of entire building

consMurtcd from sheet metal.

fronts

CONSTRlCriON Sheet-metal cornices have heretofore,

measure, l>een

in a great

duplications of the designs commonly em|)loyed in wood, which, turn, with minor modifications, were imitations {»f stone.

With the marked advancement of need no longer be the tive.

It

j)os.sesses

ca.se.

a variety

A

this industry,

.sheet-metal corni«'e

and beauty peculiarly

is

its

however, not

now

own.

in

this

imita-

.\'o

j»at-

complex or too diilicult. I )esigns are salisfact«»rily e.\tH-ut«il in sheet metal which are imjM>.ssible to product' in any other material. free and judi«'ious aj)plication of j)res>ed metal ornaments, a liy the lern

is to«)

pn»
is

For bo|dnes.s of figure, obtained that eijuals carved work. lines, sheet-metal work takes the leail of all coim-

and clean-
sharj)

|»ctitors.

In onler that there nuiy be no misimdersianding as to the various onlained in what the sheet-metal workir ealls a "cornice." I

'„

.

in tlu-

>.»

ha.i

been prepared, which

giv«'s

"entablature" — the architeitural

2aA

the

nanus of all the meiMbers for what in Uu* .sliop ia

name

SHEET METAL WORK

194

The term

known

as the cornice.

among

mechanics, a veiy general use of the word "cornice" having

supplanted

it

in the

common

"entablature"

language of business.

seldom heard

—

An frieze,

is

entablature consists of three principal parts the cornice, the and the architrave. A glance at the illustration will serve to relation that each bears to the others.

show the

the shop term for architrave

is

Among mechanics

foot-moulding; for frieze, panel; and for

cr

i—- i

/dentil mould q,0

STILE

£

1 UJ

QUARTER ROUND

COVE I

u

_l UJ

PANEL V

PANEL MOULD

i— u

Z

\

I

WA5H J

'"ILLET

y QUARTER ROuFTd^

X o a. < .JL.

OQ O

FASCIA

-I

o DRIP

FASCIA Fig. 255.

the subdivisions of the cornice, dentil course, modillion coixm^, bedIn the modillion course, are the modiUion-

mould, and croum-mould.

band and mod ill ion-mould; while in the dentil course are ihe dentilhand and dentil-mould. Drips are shown at the bottom of die crownand foot-mould fascias, and the ceiling under the crown mould is called the planceer. The edge at the top of the cornice is called a lock, and is used to lock the metal roofing into, when covering the top of the cor-

226

SHEET >frrAE WORK

195

In the panel, tliere are tlie panel pruper, the paael-iiwuld, The side and fmnt of the inodilhon are als4) shown.

nicv.

aii
the Mile.

2')<>

Fij;.

shows the side and

fr«int

view of what

<s

known

as a

Lar^e tenninal brackets in cornices, which ])roject l)eyond the niouldin^'s, and a;;ainst which the hracket.

nionhUngs end, are caUed trnsses, a front and a side view of whidi are

shown

ill

above which

Fi^.

tlie

hlfx'k,

stop

'2'u

A

.

common

a

hlock phiced

bracket

a<;ainst

monlding ends, is calle
which are shown

Fig. 250.

in Fig. 25S. 2.jU

F'i<^.

tion of iiiiiiiiiii i iii i iii i iiiiiiii i i

u iiiii

is

tlie

front eleva-

a cornice, in which are

sliown the truss, the bracket, the modillion, the panel.

It

is

dentil, and the

stnnetinies the case,

in the construction of a cornice,

that

a

bracket or modillion

whose

called for,

is

and sides

front

are car\e«l as .shown in the fmnt an«l side views in

F^ig. 2(50.

In

that case, the brackets are ol)-

tained

fmnx dealers

in

pressetl

ornaments, who make a

specialty

of this kin«l of work.

FRONT

SIDE aj)[)lics

Imk.

unins, such

in .sheet

ca|>ital

dered 2r)3,

A

metal, and

the

antl

sol-

purcha.se«l

In

in

position. .shows an

moulding, which, general

be reipiircd for

shown

tho.se

would be formed

oolinnn

up

a.s

'-ViT.

in

Figs. 2G1 and »

'I'he

2l'i2.

j

blasters or col-

The

pilaster or

r !

liu

inclined a.s

is

position cenied, would be the

far as

front

same

SIOC Fi«. 2.VS.

con-

as a gable monlding.

2'27

same

capitals which would

to

SHEET METAL WORK

196

Raking inouldings are those which are incHned as in a gable or pediment; but, inasmuch as to miter an inchned moulding (as A) into a horizontal moulding (as B and C), under certain conditions, necessia change of profile, the term "to rake," among sheet-metal workhas come to mean "to change profiles" for the accomplishment of

tates ers,

FRONT ELEVATION Fig. 259

Hence the term "raked moulding" means one whose has been changed to admit of mitering. The tenn miter, in common usage, designates a joint in a mould-

such a miter. profile

ing at any angle.

Drawings

foiTn a veiy important part in sheet-metal architectural

FRONT ELEVATION

SIDE ELEVATION Fig. 2G0.

An

work.

elevation

is

a geometrical projection of a building or other

—

on a plane perpendicular to the horizon as, for example, 259 and 263. Elevations are ordinarily drawn to a scale of | or

object, Figs.

228

>liHKT MHTAI. \

iiuli

ti>

till'

a.s,

for

A

fiMit.

(itluT <»l)ject as

example,

.^fctionul

would

it

a|)|)ear

2').*).

Fij;.

WORK

19/

drawituj sliuws a view <
Detail draw'mtfs arronliiiarily

full size, ai.d

A--

SEC

i

ON


iUN

.V/. / ....

Fiu.

-'t,!.

Fit;

are often called work'nuj drawhuja.

made

\>y traciii
iipon traiisparct't

2(V.>.

Traeinrjs are (iii|iiicate
i-lotli

Fi»?. 2rt3.

inal

drawiiij;.

eiioiigli,

we

general

]Miint.s.

M-inv other terms might l>e ititrodiiccti her«'; l>nt ha '•' l>«'eii presented to give the student the leading

lielieve,

22(i

SHEET METAL ^NORK

198

A few

words are necessary on the subject of fastening

the cornice

to the wall.

Sheet-metal cornices are

made

of such a

wide range of

sizes,

and

are required to be placed in so many different locations, that the methods of construction, when wooden lookouts are employed and

Fig. 264.

when

the cornice

is

put together at the building in parts, are worthy of The general order of procedure in putting

the most careful study. up,

is

as follows:

The

foot-moulding or architrave a b (Fig. 264) is set upon the up to /, the drip a being drawn tight against the wall.

wall finished

The brickwork is then carried up, and the lookout A placed the wall being carried position.

A

board

B

in position,

up a few courses higher to hold the lookout in is then nailed on top of the lookouts (which

should be placed about three feet apart) ; and on this the flange of the foot-mould b is fastened. The frieze or panel 6 c is now placed into the lock B, which is closed and soldered; when the lookout C and the

board

D

are placed in their proper positions^ as before described.

230

siiKi
The

plaiifeer

ami

work

M9

d an- iiow lucke«l and

l»oul(l c

.s<»l(lere
at

1>, and the Io<jk(iUt E phiceil in position, with a lx)ard F phicetl under t!>e liHikoiits the entire lenj^th of the cornice; onto this l>oard the j>lun-

ceer

is

Having the

fastened.

|)n)j)er

measurements, the framer now

constructs his lookouts or hrackets (I II I H, fastening

T, when the crown-mould d

tt)

the

beam

at

fastened to the plani-eer, through the at the and top at r. The joints l)etween lengtns

flange of the drip at d, of mouldings, are made

c is

by lapping,

riveting, or bolting, care l>eing

taken that they are joined so neatly its to liide all indications of a seam when

and viewed

finished

from a

sliort

distance. If

brackets or modillions are to

in position, they are riveted or bolte
be placed of

l)ack

cornice

tiie

is

I

"T

"'"^''°*»'

j

blocked out

with wood, and the brackets screweil in

position tlirough their flanges. \Miile a galvanizeil-iron cornice

wooden lookouts

thus constructed on

a long time, a strictis obtained cornice ly fireproof only of for supports and the metal use by will resist fire for

fastenings, to

w(H)d.

This

Ntniction

is

the entire exclusion of

method

flrej)roof

shown

of con20.';.

Fig. in

In-

20.').

Fig.

stead of piitting up ill j)arts on the l)uilding, the c-ornice stnicted in one piece in the shoj) or upon the ground, an
bottom of the foot-mould, and the

di(ate
and

r,

with a lock at d.

joints nuidc

Hand

in the

is

i-on-

lioisteil is

used

way

in-

and braces shown bv .\ \\

iron supp«»rts

are \iscd, formc(l to the general ctiutour of the parts as ( ', an
When to the

the cornice

main brace, as

fastening.

and

I.,

hi> wall,

which holds the then framrd

jus

at (',

with an cud

If tlie c<»rnice sets perfectly

hark

iirr

on the wall

.sets

at I>

iisn.-il

up or d«»wn

iM>^itii>ii.

nwiimer and

881

l>«'ut

for

phnnb. the nut.son carries up

c«»rni
in flu-

anchors are fastenni

ct)vere
The

top and

bv the metal

SHEET METAL WORK

200

roofer.

In constnirtiiif^ cornices in this manner, the nionldiniis are The brackets solid, behind jill l)rackets and niodillions.

run througli

and niodilhons are attached by means

of riveting through outside

flanges.

SHOP TOOLS One of the most

important tools in cornice or architectural sheetmetal working shop is the brake. On those operated by hand, sheets In the laCrger shops, are bent up to 8 feet in one continuous length.

power presses or brakes are used, feet in length, the press

in

which sheets are formed up

to 10

being so constructed that they will form ogees,

l)en(ls in one operation. squares, or acute <S- f)r 10-feet squaring shears also form an important adLarge dition to the shop, and are operated by foot or power.

\Mien cornices are constructed where the planceer or frieze is verv it is usual to put crimped metal in, to avoid the waves and buck-

wide, les is

showing

in the flat surface; for this

purpose the crimpitig machine

used.

In preparing the iron braces for use in the construction of fireproof cornices, a punchltu/ machine and slittimj shears are used for cutting the band iron and punching holes in it to admit the bolts. \Miile braces are sometimes bent in a vise, a small machine known as a

In large fireproof building necessary that all doors, window frames, and even sashes be covered with metal, and made in so neat a manner that,

hra^e bender

is

constructions,

of great value in the shop.

it is

grained, no differences will be apparent to indicate whether the material is wood or metal, the smallest l)ends down to \

when painted and

inch being obtained.

This, of course, cannot be done on the brakes

done by means of the draw-hcnch, which is conin structed lengths up to 20 feet and longer, operated by means of an endless chain, and capal)le of drawing the sheet metal over any shaped wood mould as tightly as if it were cast in one piece. The smaller

but just mentioned,

is

shop are similar to those described in the Instruction on Tinsmithing and Sheet Metal Work, Part I. Papers tools in the

METHOD EMPLOYED FOR OBTAINING PATTERNS The

to cylinder developments as explained in principles applied

the Tinsmithing and Sheet Metal Work courses, under the heading of "Parallel-Line Developments," are also applicable for obtaining

232

SHEET Mtrru. WoKK llif

jialicni.^ fur :iiiv iiiiMil«liii<: wlu-ii-

makes

method

uris«'.

is

ehiefly

which

ill

is

j)rulile

one another, the

to

|»aralUI this

what

Wiirereiiee

int

method

To

is inilir i-iitfiinf.

are to

l»e

anjjie of

joined

IK)*^,

The

L'tit't.

as

woukl he

first

to

an^Ie an
t)

the

make

on

iiitiin};

will

(ex-

e<.rnief

90°

V^-T"',

initrr-

that

and he would

kin.

If a

a joint of this kind,

and cut one

in the miter-l)ox, l.")°,

While

use«l.

step necessary the j^iven

olitaiii

had

sitifui l)eforo

it

l)ise
and cut each piece so they wnidd miter to^'et her.

of

for

at

in Fi<;.

linf

<arj)°iiter

lei;

>iippo -c two piece-r of moiildin;;-^

illiistrite,

lo^'elher

shown

is

I

the lines nin

work, other proMems rriaiij^'iilation" methoijs

plained in previous Papers) will lu- of >erviie. 'I'lie term used in the >hop for pattern ;,'enerally

work

a.s

Imig

in corniee

"Kadial-I.iiu" and

l!ie

run para

iiu-iiiIhts

:(ll

eiiiiiloxed, Mt

i>arallel-line

employed

2xi\

j>iece

ri<,'ht

-'till.

he would

|)lace his

and one pie<e

moulding' an aiijjie

left at

careful to hold the moulding in its proper posawing; or else he may, instead of having a return miter as shown, have a face miter as in l»e

I

frame, shown in Fig. sheet-metal cornice-

|»ictiire

'I'he

L'(i7.

maker cannot, is

\.

l>o\

»o.

XJLU FIr.

:it>7.

after his

formed, place

lay

out

moulding

in the miter-

the miter, hut

cut

to it

it

—

or, in

must

other words,

develop it—on a Hat surface or lie nmst also he

sheet of metal.

careful to place the profile in its piopi-r |>o.sition with the miterliu'-'; or else, instead of ha\ing a return miter as shown in Fig. L!(i(>, lu* will

have a face miter as shown

corre«tly,

when l<M,k

he can (hen cut two

in Fig. 2
jiieces,

a miter will result hetween as

shown

^howti in

l''ig.

i*i

Fig. LMWJ.

'ji\7,

which

is

If.

lln'

fonn om-

If

he lays out his w«trk

and the other

left,

two pieces of moulding and

will

right

|iowe\cr, a face miter

used

when miters

an-

and other purjMises, the method of laying them out we ppweed. The same principles reijuired for

is

desinil. as

d«'sir«s|

will lie

esplaiiml as

de\i'|oping

and

Uti?

are

\isvt\,

whether the mouldings are mitereil

2.T1

at

for panels

I''igs.

"Jllti

angles oflH/'

SHEET METAL WORK

202

or otherwise.

The method

of raking the mouldings

their profile to

words, changing moulding at various angles

—

will

—

or, in other

admit the mitering of some other also be thoroughly explained as we

proceed.

VARIOUS SHAPES OF MOULDINGS The

of mouldings arising in the cornice shop are style chiefly and are obtained by using the arcs of a circle. In some cases, Roman, Greek mouldings are used, the outlines of which follow the curves

of conic sections; but the majority of shapes are arcs of circles.

In

Fig. 269.

Fig. 268.

268 to 272 inclusive, the student is given a few simple lessons on mouldings, which should be carefully followed. As all pattern-cutters are required to draw their full-size details in the shop from Figs.

Roman

small-scale drawings furnished

must understand how

to

by the architect, it follows that they draw the moulds with skill and ease; other-

Fig. 270.

Fig. 271.

wise freehand curves are made, which lack proportion and beauty. In Fig. 268, A shows the mould known as the cyma recta, known in the

shop as the ogee, which

is

drawn

as follows

:

Complete a square abed; draw the two diagonals a c and b d, intersecting each other at e. Through e, draw a horizontal line intersecting

adatf and

6 c at h.

Then, with

/

and h as

spectively the two quarter-circles a e and e

2.34

c.

centers,

draw

re-

Cupples Hall, No.

2.

Building is 207 FulI L.,u^, i. i Engineering; Second Floor, to

. v ., ij^lectrical

>..

First Floor Devoted to Mechanical

Engineering.

The Library. The Building is 257 Feet Long. 46 Feet Wide. " The Reading Room is 100 Feet by Feet. The Stacks tor Books Have Room for Over 400,000 Volumes. Cost of Building, $250,000.

Busch Hall, the Chpmical Laboratory.

Ih.- 1!iiu.Iiiil;

i>.::;ni i',-.i

L.,ug,60Feet Wide.

THREE FIREPROOF BUILDINGS OF THE UNIVERSITY OF WASHINGTON, Illustrating the Restful Effect of a Long,

41

CostJUO.OOO.

ST. LOUIS, MO.

Almost Unbi-oUen Roof -Line.

SHEEl In

h

H shows

Fiji. -•"»!K

(Hfir, rcversetl.

d and a

r

WORK

tlu- rt/inu rtiTr.ia,

'oniplete u

(

.\ifc:iAl.

square a h

r d,

2(A

known

and «lniw

shop as the two lUimonuls

in the tlie

thnai^h r, draw a vertical line intersecting which points are the respective centers fur tlie arcs

interseetinj; at «;

abut } and

r

d

at

//,

a f an
C is

in Fig.

270 shows the

cavetto, calle
whidi

drawn hy

the

I) I )raw coni]>lcting a s(|uare a c d. diagonal h d at 4o°, which pn)ves tlie

using d as a center, (|uarter-(ir(le a c In Fig. 271, 1) represents the s(|iiare;

rchinun,

and,

known

rnund, which

is

draw

7

tlie

ovolu or

the shop as the (juarfcrcon.stnicted similarly to C in in

Fig. 270, witli the c.\cej)tion that h in Fig. 271 is use
E

to obtain the in Fig.

272

is

FiK. 27.>.

curve ac.

known

known

the shop as a beadbisected, thus obtaining c, which is the

as the torus,

mould. A given distance a b is center with which to describe the semicircle a

in

b.

be drawn by the student to any deIn [)reparing mouUlings from sheet metal,

should All of tiiese pn)files sired scale for practice.

V\k. -27^.

it

is

somehnuvs m|uirrd

and bead.

richments, which are

are added in the t)giH', cove, mould must be bent to; receive these en-

tiiat iiirirlinieiils

In that case the

iisiuilly

pressed she<'t-metal work.

Thus,

view of a crown mould who.s»j oget?

in is

2.15

fmm

dealers in stanipe«l »»r Fig. 273, F reprvsents a front

obtaine
enriehetl. tlw; .section of tlie

e»j-

SHEET METAL WORK

204

richment being indicated by a 6 in the section, in which the dotted Hne d c shows the body of the sheet-metal uioukUng bent to receive the H represents i)art of a bed-mould in which pressed work. In Fig 274,

Fig. 274.

egg-and-dart enrichments mould is bent as shown by dart

is

In this case the body of the are placed. cd in the section, after w^iich the egg-and-

soldered or riveted in position.

J in Fig. 275 represents part

Fig. 275.

a foot-mould on which an enriched bead is fastened. The body of the mould would be formed as indicated by c in the section, and the bead a b fastened to it. This same general method is employed, no of

matter what shape the pressed work has.

PRACTICAL MITER CUTTING Under this heading come the practical shop problems. The problems which will follow should be drawn to any desired scale by the student, developed,

racy of the pattern.

shop and

test his

cardboard to prove the accuthe student cannot use the small brake in the cut from metal, he can use the dull blade of

and bent from If

stiff

patterns a table knife, over which the bends can be made,

when using cardboard

This at once proves interesting and instructive. Should patterns. there be any problem which is not clear, he should write at once for further information; or, should any problem arise on which he desires

236

SllKKT MlCr.VL WOltK iiifdniialioii, ilic

School

similar

l>«N»k.s coiitaiiis

will iiiforiii

liiiii

wliicli

J(I5

|trol)leiu

in

liis

text-

or will prrpart' such a pnihlein for

|)riiici|)U's.

liiiii.

The return

lirst

|>rol)lciii

will Ik* to ohtaiii the (Icvclopiiient of

such as would occur when a

iiiitcr.

around the nirner of a are

shown two methods

taiiiinjj

the

|»attcrii.

method which w ill he is

l)uililinj(, lus

apjilicalile

all

to

The

first

v^

ani,'le

^

olitaiuing

may

j

\

pat^'^^- -'*'

The

have.

second method

I

I

II

10 9

277

.1

ELEVATION

II'

Fij:.

\

descriheil

the |)rinci{)les

the plan

In

'

terns for niouldin<;s, no matter

what

in Fij;. 27t).

of ol)-

the "lon^" inetluHl, in which

are set forth

shown

a .stjuare

inoiiltliii;; hail to return

8 7'6'5'4'3' Z'

'

l'

'h

l-ig

a:n

"V7

'

is

the "short'

SHEET METAL WORK

206

rule generally

employed

when the angle

in the shop, which,

however, can be used only

H G F in plan is 90°, or a right angle.

To

obtain the pattern by the first niethotl, proceed as follows: of the mould as shown by 1, B, A, 11, drawing the coves by the rule previously given. Divide the curves into equal First,

draw the elevation

spaces; and number these, including the corners of the fillets as shown by the small figures 1 to 1 1. In its proper position below the elevation, draw the soffit plan as shown by C E F H. Bisect the angle

D

F by

the line

G D, which

is

drawn

at

G

HG

an angle of

From

45°.

the va-

rious intersections in the elevation, drop lines intersecting the miter-line At right angles to as shown. G, draw the stretchout line 1' 11',

H

upon which place the stretchout of the mould 1 11 in elevation, as shown by similar figures on the line 1' IT. At right angles to 1' 11', and from the numbered points thereon, draw lines, which intersect by lines drawn at right angles to H G from similarly numbered intersections

on the miter-line

G D.

Trace a

line

through the intersections

Fig. 278.

Then will 1' G J 11' be the desired This gives the pattern by using the miter-line in plan. In developing the pattern by the short method, on the other hand, the plan is not required. At right angles to 1 B in elevation, draw the thus obtained, as

shown by J G.

pattern.

stretchbut line 1" 11", 1

11 in elevation, as

angles to which

draw

upon which place the stretchout shown by similar figures on 1"

of the profile 11", at right

through the numbered points as shown, which intersect by lines drawn at right angles to 1 B from similarly numbered intersections in the profile in elevation. Trace a line through lines

G

K. Then will points thus obtained, as shown by 1' 11' obtained from the similar to J plan.

G

238

G

1" 11"

K

be

.^iii:i:'i

In

Fijj.

?78

shown a

is

Mi;i'AL

wouk

207

hurizontal mmiUling l»utliim

Jigaiiist

a

A miter cut <»f this kind would plane surfatr oljlitjue in elevation. be re<|uired when the return nioiilriinj^ of a ilonner window woidd butt mansard or other

against a Ui

be the return

In this case

pitclietl roof.

liuttinj; Ji^jainst

we

The

the pitched roof U.

a.ssunie

A

luetljocl of

PATTERN

'JTU.

Fig.

obtaininp; a pattern of this kind

is

shown

in Ki^'.

I,i-t

LT'.t.

.\

1?

('

|)

the pitcli of the represent n'j»resentin>,' nxif. In its proper position as shown, draw the .section 1 II. which diviilc into e<|ual spaces as .sliowii. and fn)m which, paralh'l ti» A H, tlie

draw hues

elevation of the return.

intersecting,' the

right atigh's to

AH

erect

shmt

th»'

the stretchout of the

s«-«'tinii

At

11',

right angles In

I'

hiic

)

.\

1

A

1)

fn)m

stretchout hue as

shown

b\'

1'

1

to 11',

1

1,

as .sliown.

similar li;4un's

and thniugh the ninnbcrcd

on

jMiints

tlraw lines, which intenjcci by lines drawn at right angles to similarlv tnnnberc
^S9

At

ujM>n which phuv 1'

11'.

tiiertiin,

A

li

fn»in

Through

SHEET METAL WORK

208

draw E

the various intersections thus obtained,

Then

F.

will

EF

be the desired pattern. It is sometimes the case that the roof against which the moulding butts, has a curved surface either concave or convex, as shown by B C 11' 1'

in Fig. 280,

which surface

moulding, as

D

E; and

is

in

convex.

its

Complete the elevation of the

proper position draw the section

1

9,

which divide into equal spaces as shown by the small figures, from which draw horizontal lines until they intersect the curved line B C, which of the

struck from the center point A. At right angles to the line 1' 9', erect the line which moulding upon place the stretchout is

SECTION

c Fig. 280.

shown by the figures on the stretchout line. Through points, at right angles to 1' 9', draw lines, which by lines drawn at right angles to 2 D from similarly numbered

of the section, as

the numbered intersect

intersections

on the curve

B

9" in the pattern, as shown. ductions of the arcs 2 3

C, thus resulting in the intersections 1" to The arcs 2" 3" and 7" 8" are simply repro-

and 7 9 on

B

C.

These arcs can be

AC

traced by any convenient method; or, if the radius to make it inconvenient to use, the arcs in the pattern as follows:

Using

AC

as radius,

and

7"

and 8" as

is

not too long obtained

may be

centers, describe

arcs intersecting each other at A' in similar manner, using 2" and 3" as centers, and with the same radius, describe arcs intersecting each ;

240

SHELT MKIAL WuHK A

otiier at

With the same

.

ilraw the ares S" 7"

and

.)"

nulius.

2(W

ami with A' and A' as

2" respeetively.

the other various intersections as shown.

ct-uters.

Traee a hue through

Then

will

I'

1" 'J" 9' l>e llie

desiretl pattern.

In

"J-Sl

Fi<j.

shown an

is

panel for which "panel" or "face" miter.

a miter-cut

elevation of an oblong or rectangular is

desired on the line a b

— known

its

a

The

rule to aj)j)ly in ol)taining this is shown in Fig. 2S2.

pattern

A

shows the

the

panel;

miter-lines

In

45°.

jjart

a h

drawn

its

elevation of

and

c

at angles of

proper

with the lines of


1

the

position

tiie

mouM-

the ing, draw the pn)Hle B. cun'eor mould of which divide into ef|ual spaces, as shown

hy the figures

1

to 7;

and

fn)iu

the poHits thus obtained, parto

allel

1

h,

draw

inter-

lines

I-iR. •Jsi.

.seeling

to

allel

draw

liK.

the miter-line a h as shown. /)

(I,

draw

line-s

the stretchout line

At

pndih' n.

right

From

intersecting also ril. 1' 7'.

angles

JSJ

the.se intersections,

parAt right angles to bd

upon which plai-e the stretchout of the 1' 7', and through the nundiertnl

to

which intersect by lines drawn at right d fnmi numbereints <»f inter(I Trace lines lines anti through )M)iiits

of divi>-ion.
section in the pattern

a.s

shown.

Then

will

(

1>

1',

1'

be the

re«|uin*
cut for the enils of the panel.

The same

miter-<'Uts

would be employnl

•,;»i

for the long side u c in

SHEET METAL WORK

210

D

it E in Fig. 282 that length being necessaiy only to make laying out the patttern on the sheet metal. Wliere the miter-cut is required for a panel whose angles are other

Fig. 281,

when

example, a triangular panel as shown in Fig. shown in Fig. 284. First draw the elevation of the triangular panel as shown by A B C, the three sides in the case being equal. Bisect each of the angles\A, B, and C, thus obtaining the In line with the elevation, place in its miter-lines Ac, B 6, and C a. than right angles,

as, for

283, then proceed as

proper position the profile E, which divide into equal spaces as shown; and from

numbered division points, parallel to A C, draw the

ELEVATION

lines cutting 'the miter-line

C

a.

From

these intersec-

tions, parallel to'

C

B, draw

lines intersecting the miterline.

6 B.

At

right angles to

C B draw the stretchout line V T, upon which place the

Fig. 283.

Fig. 284.

stretchout of the profile E. sion

and

at right angles to

V

Through the numbered points of divi7', draw lines as shown, which intersect

by lines drawn at right angles to C numbers on the miter-lines a C and obtained, trace the pattern

B

from intersections of similar

h B.

Through the

points thus

F G H I.

It makes no difference what shape or angle the panel may have; the principles above explained are applicable to any case. In ornamental cornice work, it often happens that tapering mould-

ed panels are used, a plan and elevation of which are shown in Fig. 285.

242

WOHK

SIIKKT MinWI, My

rt'ffrriiif;

ami

to the plan,

it

will In-

swii that the four parts h

«' b are syinmetrical; tlicrefoR*, in practice,


tion, sinc-e the height

d

v (I'V-

shown

2^3)

is

in Fij^.

1m«.

15

by a

fi

0.

Fn)ni

tiiese jxtints,

velojxxi

draw

hy

by triangulation, a

Fi^. 2s7, fur I;

and

panel fn)in

is It

2.S(),

apex

4,

5 and

1

and

a.

only to

otnit the eleva-

o,

and

9 into (»,

7, S.

As the ])attern

set of trian<,'les will

I'lK.

ami

2,S.5.

1, 2, 3,

lines to the

b', h' a',

Thus, in Fig. 280, draw what is its shape, as shown

Divide the curves from

spaces, indicated respectively

a

a,

it is riei-exsan.-

known.

the (juarter-plan of the |)anel. no matter

n

211

he

rcnpiireil.

will

as

ofjiia-

and he

'.t.

ile-

shown

in

-'sti.

which procccil as follows:

Diaw any

horizontal line, ns

a erect the perpendicular (i «' npial to the height the to havi-. Now take tlu> lengths of the \arious lines in Fig. 2S(»

to

Fig. 2S7,

fi-orn

I, rj

a.s

to 2, a to 3, etc., to a to<),

.shown

l»y

similar ninnhers.

843

and place iheni on the

Then

line o

1

in

using as radii the vari»)us

SHEET METAL WORK

212

lengths a' 1, a' 2, a' 3, etc., to a' 9, and with any point, as a' in Fig. 288 as center, describe the various arcs shown from 1 to 9. From any

point on the arc

draw a Une

1

to a'.

Set the dividers equal to the spaces contained in the

curve

1

5 in Fig. 286; and,

starting

from

1

in Fig.

from one arc

step

num-

othcx having similar bers, as

shown from

288

to an-

1

to 5.

In similar manner, take the distance from 5 to 6 and ^'

'

the spaces in the curve 6 9

in Fig. 286, and place them on corresponding arcs in Fig. 288, stepping from one arc to the other, resulting in the points 5 to 9. Trace

a line through the points obtained.

Then

thus

will a' 1

r

5 6 9 a' be the

quarter-pattern,

which

can be joined in onehalf or whole pattern as desired.

In Fig. 289

is

shown

a perspective of a moulding which miters at an

Fig. 288.

occurs when a moulding is angle other than a right angle. This or other structure whose angles vary. window for a over bay required

The rule given

in Fig.

290

is

applicable

any angle or profile. First draw a section or an elevation of the moulding

to

as

shown by A B 14

the moulding, from as

2

3,

angle as Fig. 289.

1.

its

Directly below

extreme point,

draw a plan of the desired shown by C 2 D. Bisect this

angle by using 2 as center and, with any radius, describing an arc meeting

the sides of the angle at C and E. With the same or any other radius, and with C and E as centers, describe arcs intersecting each other in F. be the From the corner 2, draw a line through F. Then will 2

H

244

SHEET METAL WORK initor-l inc. 1

|)n>tile

or

ilip line l)ist'ctinf?

14 into vt[un\

tlius obtaineti

ilitjp

('2

tlip aiifjle

as sluiwu by

.s|)ac'e.s

213

Xow

1).

the

iliviile

and from

tlie figures,

tlie

vertical line.s intersprtintj the miter-line

2

-\

I

\

:•:;:

:

111

12 ,1

, 1

.1

ELEVATION

1

,

' 1

'

-B

13

.

I

I

l|-i

n

(4

lail 109 8 7 6

5 4

T

p

I

"M

PATTERN

Fig. 290.

plan from

II in

At

angles

ri^'ht

14

to

1

to ('

2.

a.s

.shown-

draw the

n|K)n which place the stretchout of the |)rofile in elevation a.s .shown by similar figures on the line

K,

I

stretchout line, through which drop

|K'rpendicular to

lines

intersect with to

K

I

|M>int.s

line

_'

II.

Traci- a line as

shown

liy

from

linivs

similarly

of intersection I-

.1

M, which

K, which

drawn

is

parallel

mnnb«'nHl

on the miterthe miter-<'ut

desired. \N

hen two mouldings having dilTercnt

miter lt)gelhcr

lus

.slu»wn in Fig. 2*.H.

24.^

where

j)roliles ('

are reipiin^l to

miters at right angles

SHEET METAL WORK

214

with D, two distinct operations are necessary, which are clearly shown in Figs.

292 and 293.

The

first

operation

shown

is

in Fig. 292, in

which C represents the elevation of an ogee moulding miter at right angles with a moulding of different profile as

C

Divide the profile

which

shown

is to

at

D.

into equal

2 spaces, from which points draw horizontal lines

D

moulding right

intersecting

the

to 10'.

At

to the line of

the

from

angles

1'

moulding C, draw the line A B, upon which place the stretchout of the profile lar figures

angles to

C

shown by simiAt right B, and through the

on

A

as

A

B.

PATTFRN FOR Fig. 292.

points indicated by the figures,

draw

lines,

which

intersect with

drawn parallel to A B from similarly numbered intersections Trace a line in the profile D.

lines

through the points thus obtained, as

shown by

F

GH

E H. Then

be the pattern for

will

E

C

in

elevation. Fig. 293.

To

obtain the pattern fori), is to miter at right draw the elevation of (Fig. 293), which Proceed in precisely C. is angles with a moulding whose profile Divide with connection in the same manner as explained Fig. 292.

D

the

profile

which draw

D

in

Fig.

293

into

equal

parts,

horizontal lines cutting the profile C.

246

as

At

shown,

from

right angles

MhrrAL

siiKtrr

to

liiu's tif till- moiiltliii;;

till-

D, ilraw

wliith place the stretclioiit of

tli«'

wouk

21;

llif >tri't(li«)Ht

At

pnilik' I).

A

liiu-

ri}^lit

anil thniiigh tlie iuiiuIhtc*! points of ilivisioii, ilruw lines

which intersect hy Hnesdniwii parallel intersections in the profile •

Iraw

F

(

Then

;.

will

203 are fonned antl

shown

is If,

EF

G

in

iijm»ii

its

A

B,

shown,

fruni similarly nunil>ere«i

'riirou^'h these |)oints of intersection

('.

II

he the

pattern for

clesire«l

he understood that when the

shoulil

It

AM

to

IJ,

uii^U's to

joine
I

).

|)atterns in Fifjs.

will

202 and

form an inside miter, as

201.

Fig.

however, an outside

miter were

wouKl he

refjuired,

it

neccssar}' only

to \ise the reverse cuts of

the patterns in Figs. 202 EJ

and 203, as shown by in

II

202 for the

Fig.

mould C, and F J G in Fig. 203 for the mould D.

When

j

o

i

n

i

n g

Fig. 291.

a

curved moulding with a straight mouUling in either plan or elevation even though the cur%ed or .straight mouldings each have tlie

same

it

profile,

is neces.sar}-

to estal)lish

the true miter-line before

the pattern can be correctly develojied, an example being given in of a curvtnl moulding which Fig. 204, which shows an elevation is

intersecte
by

tlje

horizontal mouldings

A

The method

H.

of ol>-

for the horizontal pieces, taining this miter-line, also the pattern

shown

clearly

is

moulding

Then, with the arc

B

in Fig.

to have, as

("

on

First

20.'). 1

10.

draw the

pn)iile

Let the distance

the center line as center,

From any point on the line Through the various divisions

and

.V

is

whiih the horizontal

H be

e.stablisluMl.

("as ra
H, as n. erect the vertiinl

A.

pmlile 1 10, draw to 10 asshowii. horizontal lines intersecting the vertical linea/in ( radial line, as d, cutting the arc M A at e. From the center ( ', draw

line


I).

in the

1

'

any

Now

take

tin-

various divisions on a

/»,

and place them from

e to


Then, using (' its center, with radii deterniineil bv the various jioints on r d, dniw arcs intersecting horiz«»ntal Through Urn's of similar mu'diers drawn through the divisions on a b.

shown bv points

1'

to 10'.

1247

SHEET METAL WORK

216

these points of intersection, draw the miter-Hne shown. will note that this line is irregular.

The

student

Having obtained the miter-line, the pattern is obtained for the horizontal moulding by drawing the stretchout line E F at right angles On E F lay off the stretchout of the profile 1 10; and to 9 B.

E F, draw horithrough the numbered points and at right angles to zontal lines, which intersect with lines drawn at right angles to 9 B from similarly numbered tersections

a'.

in

the

determined by horizontal already vertical

in-

miter-line lines

drawn through the Trace a line line a b.

through the points thus obtained, as shown by H I J K,

which

is

the desired pattern.

A B

Fig. 296. is shown a shaded view of a gable moulding intersectthe vertical pilaster the gable moulding B cutting against ing a pilaster, this joint-line, obtain To c. a 6 A, the joint-line being represented by

In Fig. 296

without which the pattern for the gable moulding cannot be developed,

an operation in which

in projection is required.

BCD shows

This

the plan of the pilaster

is

explained in Fig. 297, in elevation by E.

shown

in plan, place the profile of the gable moulding, proper position the figures as shown by A, which divide into equal spaces as shown by

In

1

its

to 8,

lines intersecting the plan of the through which draw horizontal For convenience in prosimilar figures. B C as shown

pilaster

D

by

248

MKTAL WoHK

SlIKKT

jectiiij;

varu)ii.s |x)iiil.s,

till'

and

to

2l'i

avoid a coiifusion of

number

lines,

the intersections between the Hnes «lrawn from the pntfile A llirougfi At the (h-sired in.int II in elevathe wash H 2. "7°". "4°", an
draw the lower hne

ti«)n,

of the j;able mouldinij,

II

a.s

Take a

I".

traeini; of the ])roliU' A in phin, with all of the

various intersections on

and

>anie,

in

it

j)lace

shown

as

elevation

by

A', placing the line 1 S at rifjht an^^les to II V. 'riiroufjh the various in-

tersections

1, 7°,

2, 3, 4, o,

7.

and

A',

draw

<),

in

F

11.

|)arallel

lines

4°, 3°.

and S to

indefinitely,

which intersect by

drawn

H

("

plan fnini sim-

in

ilarly

lines

at ri^dit an<jles to

numbered

intersec-

tions in the pilaster

H,

t

h

11

s

T

[)oints of intersection

to

I)

the

obtainini:

1"

S* in elevation.

For the pattern, (cvA as follows: At angles to

draw

II F,

^t^•tchout line

j)rorij^ht

.1

the

K, upon

which place the stretchout of the pn)(ile A or .V, with all the points of intersection I

2.

At

lines as I''

on the wash ri/;ht

anodes to

shown, which

I

K, and through the nuntber«Nl

intersect

fn)m similarlv numbered

by

lines

drawn

inlerse<-tions

in

j>oints,

draw

at rij;ht anj^les to II

the

j«>int-line

MN

Throu^'h the points thus obtained, trace iIm- miter-cut will I, \ ( ) I' be the pattern for tlu- jjable mouldiiifj.

(

l"

>.

S*

'I'hen

M

In Fiy.29S are

shown pable mouldings miterinn

•jji»

uj)on a wash.

The

SHEET METAL WORK

218

A A intersect at any desired angle the wash B.

In this case,

as in the preceding problem, an operation in projection

must be gone clearly shown

mouldings

through, before the pattern can be obtained. in Fig. 299.

This

Draw

is

the section of the

horizontal moulding B^ with the wash a b. From this section project lines,

and draw the part elevation ^^S- ^^^-

have,

draw C B,

Knowing

D

C.

the bevel the

in this case the top line of the

gable is to moulding. Draw a

which divide into equal parts as and through the point of division draw lines

section of the gable mould, as A,

shown from parallel to

B

A, and place

1

to

8;

C, indefinitely, as shown. it

in section as

shown by

Take A'.

a tracing of the profile A into the same

Divide

PATl

ELEVATION

SECTION

Fig. 299.

number

of spaces as

A; and from the various divisions in A* drop wash a 6 as shown, from which points

vertical lines intersecting the

draw

horizontal

lines

intersecting

lines

drawn

parallel

to

B C

through similarly numbered points in A, at 1° to 8°. Trace a line through these intersections as shown, which represents the miter-line or line of joint in elevation. For the pattern, draw any line as

E F, at right angles to B C, upon which place the stretchout of the profile A, as shown by similar figures on the stretchout line E F, Through the numbered pomts of division and at right angles to E F, draw lines as shown, which intersect by

250

SIIKK'I

lilies

tlrawii at

tioiis

on

rij^lit an;,'lr.s ti»

1° ff anil

on

tlu-

MKTAL WOHK |{

('

219

fnmi similarly

vertical

line

15

1).

A

niiiiiltertti

iiUersec-

line trace«l tlinrnj^li

as shown Ity I, uill he tiiedesiretl pattern. shown a fnjiit view «)f a turret on which four j:aljles are to he i)hice
|)oiiit.s thii.sc)l)taine
Ill

1

i

I

1

Fifj. 30() is

the developments of the jjahle on a square turret. In developing

sists in ohtaininjj

moiihlinfjs

this pattern, the half-elevation

shown center Hne as

Fig. 301, in

in

E

is

only

which

.-J

A

rtH|uire
draw the

first

F; then cstahlish the half-width of

C

the turret, as

I),

B

and draw the rake

riuht annjles to tlic line

B

and

( '.

in

its

C.

At

j)n)j)er

position as shown, draw the prf)file .\, whicji divide into ef|ual spaces as shown hy the Hjjures 1

which, parallel to B C, draw lines intersecting the shown; and extend the lines helow (", indefinitely.

lo 0, throuj^h

FE

center line

Now

as

take a tracing of the profile A, an
shown hy

shown from

divisions, as

FiK. 300.

1

lines intersecting similarly

to 6,

through which,

numhered

lines

it

position as of

in

same numher

j)aralk'l to

D C, erect

drawn through the pmfile

A, thus ohtaining the intersections 1° to G°, through which a line is traced, which represents the line of joint at the lower end hetween the two gahles.

For the J

j)attcrn,

take a stretchout of A. and |)lace C, as .shown hy the figures

K drawn at right angles to B

it

1

on the to

('»

on

line .1

K.

At right angles to .1 K, and through these p«)ints of division, draw lines, which intersect hy lines drawn fn)m similarly numhere
1" li

anrl

shown hy

1'' (')°.

'Trace a line through the |)oints thus ohtaine
B° C°

1*^

are rciiuin-d to complete the turret, four formol right and four left. If the roof shown hv B in Fig. '.)()() is desire
pattern in Fig. ejpial to

F

P

F' then, at right angles to V^ (l®, draw the line the half-elevation, and draw a line frum F' to ••'^ in the

.'{(ll.

II in

pattern.

In Fig.

302

is

shown

zontal returns at l)ottom

which

will follow, a

front vij'wof .\

an angular pnlinient with

and top H.

change of

pn)lile is

S51

lu)ri-

In this pntl>leiii, as in othets i)efon' the otrreet ne«'e."vsary

SHEET METAL WORK

220

In other words, a new propattern for the returns can be developed. or from normal the file must be given profile before the patdeveloped

can be developed. It should be underare given profiles always divided into equal spaces; there-

terns for the required parts

stood that

all

fore the modified profiles will

contam unequal spaces, each one

oi

^i

I

I

HALF ELEVATION Fig. 301.

which must be carried separately onto the stretchout line. Bearing this in mind, we shall proceed to obtain the modified or changed proof a gable files and patterns for the horizontal returns at top and foot moulding, as at B and A in Fig. 302, the given profile to be placed in the gable moulding C.

In Fig. 303,

let

C

I

represent the gable moulding

I 2.52

I

MiKivi'

nljKtil at iiij;

pn)pcr an^'lo with

its

Mrr\i.\vr)nK Imri/ontal

tlie

221

iiiouldiiitj

As.smu-

(ill.

the prujuT an<jU'. place the ^iveii pn>file A at right to the rake. a.>< .shown; and divide .same into e<jiial .spaces as

that

aiij^le.s

(»"

<)° is

fmm 1 to U). thn)U^h wliich |)«>int,s, parallel towards the top and hottom of the

to 6*

.shown

()*'

('»"

t-orreet,

is

draw

take a tracing;

^.

of the j)rofile A. an
and

(1

the

in

lines

.V-ssuniin^ that the

rakiiif^ nionldin<;.

lenj^th

O**,

t«»

have the

j)n)files directly

''n

jjoints FiK. 303.

a ver-

From the vatical position below the jioints Vi^ and ()°, as .shown. contain tlie A" mu.st A' and (which the in rious intersections profiles same ninnber

of spaces as the

fi:iven

A), erect vertical lines

j)rofile

drawn through the j)rofile A, as .shown at the lower Trace a line lO'', and at the ui)per end from 1° to K)®.

intersectinj; lines

end from

P to

P

lO'^ be the modifie«l Then will througli the points thus obtained. for the lower horizontal return, and 1° 10° the moditietl prt)file |)n)hle

fur the upj)er liorizontal return.

Note the difference in the shapes an
from

(\^

to 10'.

For the

jiattern

right angles to

K

F,

for the gable

draw the

moulding.

the stretchout of the given pri)(ile A, as J

K.

Through

lO* at

the lower cud.

tained.

Then

Vov the

will

lines

shown by the

drawn

intersections

lunuln-rcd

1

p.ittiTM

in

Tra(«> a line ,

M N

(

for tile

at right

1°

as follows:

10° at

1

fig\ires

1

lOon

angles to V. V Inun the top and T »•''

lhr..,igii th<- infersecticuis

bi- tlic

to

K, draw lines as

pattern I'm- '. horizontal rt'turn at thetoj».

)

At

K, u|x)n which place

.1

these figures, at right angles to

shown, which intersect with similarly

j)roceetl

.stretchout line

thus

ol>-

(

draw aside

view as .^howii at H, making I' K the desired |)rojection. and the pntlile 10 «»n H. with it.s various intersections, an «'\act n-pnxluction of 1

1° 10° in the «'Ievation.

from I

10. lay off

to 10 i>n

U

S.

right angle-, to

Extend the

the stretchout of the

line

pr«>lile

K in

T H

as

as

II

."-1;

an«l. starting

shown by the

figures

being careful to measure each spa«-e separately.

U

.-^

ilraw

tin-

usual measuring lines,

a&.i

which

At

intersect

SHEET METAL WORK

222

by

drawn

lines

UV

parallel to

S

R

from similarly numbered points

in the

through points thus obtained. Then will 10 1 be the pattern for the return B. In similar manner, draw the side view of the lower horizontal

profile in

shown

return as —

ru
Trace a

B.

^ m

at

coNqj

line

D, making the projection o>9

W 10

equal to

P R

(-

CO o CO

S

— in B. to

The

be an

shown from

1

o)2

to 10 in

X

D, with

all its

divisions,

exact reproduction of the profile 1^ to 10^ in elevation.

the line W' 1

profile

(\iir)tu)
X

as

X Y,

upon which

all

unequal.

Extend

lay off the stretchout of the profile

10 in D, being careful that each space

as they are

is

Thiough

is

measured separately, X Y draw lines as

the figures on

254

METAL WOHK

'IIHET

i23

W

\ from tl»e variou.s shown, which intersect by hnes
thus ohtainetl, as \'

will

he

t]ie

desired cut, and

1

Z

10 the pattern for the return D.

In Vi^. 304

is

shown a

front view of a segmental pe
upper and lower horizontal

presents a pn)l)lem of obtaining' the pattern for horizontal returns at 'I'his

to[) and foot of a segmental pediment, shown respectively at A and H. the

The

given profile to be place
'

'>^

'*'"

these patterns are similar to tliose the problem, only difTerence being that tlie moid
j)rinciples

in

obtaining

in tlie preceding

ing

is

given.

First ilraw the center line

B

D, through which draw the horizon-

-^--H

»^

tal line (' f

''.

Fn)m

dcsire
a.s

"

the line

(

C establish

H, draw the arc

the heigiil

K ami with the ,

*

]•]

(

interse«ting the line ('

(' at (',

proper |M)sitionon a vertical line F (1. parallel to I) H, draw the ^^ivcn pnililc of the cuncd moulding as shown by A, which divide int«» In

its

e
F

(i,

.shown

draw

fmm

1

to 10.

Through

tlu'se (igures. at right

lines intersecting the center line 1>

fins

H

as

shown.

SHEET METAL WORK

224

B

as center, with radii of various lengths corresponding to the various distances obtained from A, describe arcs as shown, ex-

Then, using

The point of the pediment. tending them indefinitely below the foot with all the of the a take C or 6" being established, tracing profile A, it as shown and in intersection of various points same, by A^ place the A^ come below in 6 the to have careful point directly point being Then, from the various inter6" in elevation in a vertical position. sections in A- erect vertical lines intersecting similarly

numbered

arcs

Trace a line as shown from 1" to 10", profile A. the modified profile for the foot of the curved moulding.

drawn from the which

is

Establish at pleasure the point V at the top, and take a tracing of the given profile A, placing it in a vertical position below 1', as

shown by A^

From

the various

intersections in A^ erect vertical lines intersecting similarly

num-

bered arcs as before. these intersections,

T

Through shown from

to 10', trace the profile

which

is

shown,

the modified profile for

the top return.

The

curved moulding shown in elevation can be made either

by hand or by machine. general method

The

of obtaining the

blank or pattern for the curved average a line through the extreme points of the moulding as I J, extending it until it intersects a line drawn at right profile A, is

angles to

We

to

D B from the center B, as B

H,

at

K.

not go into any further demonstration about this curved matter will be taken up at its proper time later on. as the work, To obtain the pattern for the upper and lower return mouldings, will

proceed in precisely the same manner as explained in connection with returns

B and D

in Fig. 303.

In Fig. 306 are shown the plan and elevation of a gable moulding This problem should be carefully followed, as it in octagon plan. in presents an interesting study in projections; and the principles used solving this are also applicable to other problems, no matter what

angle or pitch the gable has.

By

referring to the plan,

256

it

will

be seen

SIlKE'l"

225

moulding has an octuf^on aii^lr in plan u h c, while .similar c' run on a rake in one line, the top aiid foot

that tlif

in elevation «' //

points of tlie

MK'IAL WuitK

moulding hutting against the hriek piers li an«i A. of pHx-ettlin^ with work of this kind is exjjlained in Ix't in V'\i^ 307, where the principles are thoroii<,'hly explained.

The method detail

'

A H

<

•

I

muuldinu

1.

is io

which a j^aM* represent a plan view of the wall, over I II. the ^^iven be placed, as shown hv < pmfile of the I

!

?E

SOFFIT P:»N

:U)7.

FiL'.

)ivi(io tlir profile into equal spact»s nouldin^ hoinjj shown l>y I, M. shown liv the li^'iiri>s to s. Parallel to II or (J. and thn>ui;h ihe Bisect the ai^jle fi^'ures mentioned, draw lines imlclinitely as shown. 1

ns

H

'

(

f)

in |)lan.

and obtain the miter-line as follows: With N ). With N and ( as

and anv radins, describe the arc '

unv radins other

at

jfreater

r

than

(

N

I'ntm the point '

die miter-line

<

.1

1

1

t^.

or ('.

)

(

(' ().

(' jis

piiililc

ijft?

and

describe an-s intersiftinj; each

and lhron^;h the interseition

Transfer the

center,

centers,

I -

M

in

1*.

elevation to the

draw |M»si-

SHEET METAL WORK

226

shown by R S in plan, dividing it into the same number of spaces Through the figures in the profile R S, and parallel to D C, draw lines intersecting the miter-line C Q, as shown. From the intersections on the miter-line, and parallel to C B, draw lines intersecting

tion as

L M.

the surface

B

A.

Now,

at right angles to

C

D in plan,

and from the

SOFFIT PLAN Fig. 308.

intersections

C Q, draw vertical lines upward, internumbers drawn from points in profile L in

on the miter-line

secting lines of similar

M

A

elevation parallel to J G. line traced through points thus obtained, as shown from 1' to 8', will be the miter-line in elevation.

For the pattern for that part of the moulding shown by and H G 8' 1' in elevation, proceed as follows:

in plan,

angles to

1

H

in elevation,

draw the

258

line

T U,

C

D E Q'

At right

upon which place the

MK'I'M

SIIKK'I'

WORK

227

At rij^ht I^ M, as shown hy the Hj^ures 1 to S. r, and throuf^h these figures, draw lines, as shown, wliich H intersect with Hues of siinihir nunihers drawn at rij^ht anjj;les to

.stretchout of the pniHIe to

iii»i;h's

'I'

1

from

on the

intersections

against the vertical surface

shown

lus

ol)taine
niiter-line

H

\V

l)v \'

S'

and

intersectioas

fnjni

Lines trace
(J.

X

1'

Y,

will

in plan by C U E Q' of Fig. '.0)7. on the other hand, the j)osition of the plan is changed, .'iOS, A Q horizontal. At right angles to \i T draw the line hring

shown

the gahle

In Fig. so as to

f

In the same E, on which locate any |X)int, as K. J C line B draw the vertical manner, at right angles to B, intlehnitelyFr')ni the point E, parallel to B C, draw the line E S", intersecting

the vertical line

Now

the line J B, as shown.

and

tion, Fig. 307,

fn)m J

Now

moulding. line

Z Z

set

off

it

from S" toward J

Draw

in Fig. 'MS.

a line

of the represent the true rake for this |Mjrtion take the various heights shown frt)m 1 to S on the

which

to E,

take the distance from S" to J in eleva-

will

and

in elevation in Fig. 307,

them as shown hy Z Z

i)lace

in

elevation. Fig 30S, being careful to jilace the point S of the line

Z Z on

E

the line S"

extended.

and from points on same, draw with lines drawn at right angles to Z,

numbers on

tions of similar

through

points tlius

From parallel

Q

E

draw

J,

lines,

B

C.

A

line trace«l

DE

in eleva-

in plan.

which intersect with

intersections of similar

at right angles to

from intersec-

the miter-line I) E, and

the intersections on

to

drawn from j)lan

C

B C

in plan.

shown by

obtained, as

be the miter-line on

tion, will

Q

C

At right angles to Z which intersect

lines,

A

line traced

lines

AB

mnubers on through

in

jwiints

shown by F J, will be the miter-line again.st the pier shown in plan by B A.

thus oi)taineil, as

or line of joint

Before obtaining the pattern section or |)rolile at right angles

ceed

lus

follows:

it

t«)

will In-

necessary

the moulding

'i'ransfer the given pi"olilc

I.

F

M

1

>.

t«>

.^.^—^ ''K- ''^^^

obtain a true

To

«lo so,

pro-

in elevation in Fig.

307, with the divisions and figures on sanu-, to a position at right angles At right angles to F D. and fn)nt to F ) of Fig. 30S, as .shown at I.. i

the interstM-tions in the iar n(Miil)ers in

F

1

)

I''

|>ro(ile I.

E,

Trace

draw

lines inter.se<-ting those of sinii-

a line fhn)Ugh interse<"tions thus

2an

ob-

SHEET METAL WORK

228

tained, as

shown from

at right angles to

F

1

to 8, thus giving the profile

M,

or true sections

D.

For the pattern, proceed as follows: At right angles to F D, draw the line H K, upon which place the stretchout of the profile M, as shown by the figures. At right angles to H K, and through the figures, draw lines, which intersect with those of similar numbers drawn at

Fig. 311.

Fig. 310.

from points of intersection in the miter-lines D E and J F, as shown. Lines traced through points thus obtained, as shown by N O P R, will be the pattern for the raking moulding shown right angles to

F

in plan, Fig. 307,

D

by

AB C

Q'.

In Fig. 309 is shown a view of a spire, square in plan, intersecting In practice, each side A is developed separately in a four gables. manner shown in Fig. 310, in which first draw the center line through the center of the gable, as

E F.

Establish points

260

B and

C, from which

WEE'V MK'l'AL WollK At

tlraw lines to the apex V. to

F

fmiii

aii«l

K,

H ami

For the pattern, take the distances as

shown hy

on the

A

pleiLsure. estal)li.sli

draw the

.1,

229

B

lines

K.

K

H

1

A, and

A

At right angles

).

J

II antl

F,

K

respectively.

and place them

similar letters

B F

vertical line

e

^

in

SIDE

B

At right angles

^11.

Fi-:-

to ]{ F.

and

H and

A.

thnuigji points lines as

draw

shown, making B II and li II' on the one hand, and A X an«l A O on the other hand, li

to

etpial respectively

AX

II anil

in elevation in

Til en,

Fig. 310.

in

Fig.

.-=*!

Fig. 312.

31

draw

1,

Fig.

lines fn)ni

X

H

to

to

K

1o

fl'

to

O.

its

MA.

shown, which repre-

sents the j>attern for one side.

In Fig. 312 is .shown a perspective view of a drop B mitering against the face of the bracket (' as indicated at A. The princij)le.s

and can he apthe j)rofilesof «ln>p or hrneket B (' 1) F represent the faceor fn)nt view of thehnieket Divide one-half I the side of the ilrop and hrackel.

for developing this prohleni are explaine
to similar

I

Let

he.

may

droj),

and

I"

1

work no matter what die

.\ 1

<

i

of the face, as 1) C,

in sid«-

IH!, ilraw

out of the profile B angles to .sect

.1

shown

on

II

<

1

»,

as

tlu- line

shown

.1

l>y

the figures

l>y

1.

drawn

parallel

to

,1

to 7

cro.>vsing II (i

at

points

1' t<»

1

K fmm

Tra<-e a line through the

2i\\

1

K, n|M»n which place the stretch.\t right to 7 to 7 to 1 on .1 K.

K, draw the usual measuring lines

lines l»y

tions

ecpial sj)aces, as

side,

In line with

7'.

intf)

from which points draw hori/onial lines view and intersecting the face II I of tlu* hracket

on either

a.s

shown, which

similarly mnnlu'n'd |M)int.s

inter-

inier.iM'^

thus ol)|aine
Then

SHEET METAL WORK

230

will J

K L be the pattern for the return of the drop on the face of the

bracket.

In Fig. 314,

A shows a raking bracket placed in a gable moulding.

When brackets are placed in a vertical position in any raking moulding, B represents a raking bracket brackets. they are called "raking" The patterns which will be developof the gable. placed at the center ed for the bracket A are also used for B, the cuts being similar, the only difference being that one-half the

width of

the

bracket in

B

is

formed right and the other half left, the two halves being then joined at the angle as shown. In Fig. 315 are shown the principles

employed

for obtain-

the side, patterns and returns sink face, strips, cap, h ese for a raking bracket. ing

the

for

T

ELEVATION

principles can be applied to any form or angle in the bracket or

Fig. 314.

T

Let S U V represent part of a gable moulding respectively. front elevation of a raking cornice placed at its proper angles with draw the outline of the any perpendicular line. In its proper position,

M

O. Also, in its proper position shown by E G draw the normal profile of the side of the bracket, indicated and X and 6-Y-Z-15 the normal profile of the cap-mould, as

face of the bracket as as shown,

by

W

;

;

the normal profile of the sink strip, as indicated by 10 10' 15' 15. Complete the front elevation of the bracket by drawing lines parallel to

E O

from points 7 and 9 in the normal profile; and establish width of the sink strip in the face of the bracket, as at

at pleasure the

J

K and L H.

To

complete the front elevation of the cap-mould of

MO

G

E and of the Extend the lines the bracket, proceed as follows front of the brackets, as shown by E 6 and 6, on which, in a vertical of the normal profiles position as shown, place duplicates (W^ W^) :

O

W

W^

and X, divided into equal spaces as shown by the figures and W^ From these intersections in W^ and W^ drop vertical lines, vhich intersect by lines drawn parallel to E O from similarly numbered 1

will

RE

()

in

X, and trace lines through the points thus obtained. and O 1^ represent respectively the true elevations, also

intersections in

Then

to

262

TM

SlIKKT MKTAl. WollK tli<

ii 111

[ii.Mii.

-.

tup ami foot uf

at

i.ir tin- ivliirii.s

tin*

cap of

tin-

rakiii^

lirackft.

Now

tliviilo

shown hy the

tliL-

iiuriiial

figures G to

15,

intersecting the nonnal sink of the bracket KFt!.

HI.

of the hraeket into etjual >pactrs, as

profile

through which, parallel to E O, draw lines from 10' to l.V and tlie face lines jirofile

KI..

and

(

)NM,

as shown.

To

obtain the

PATTERN

roR SIDE BRACKET

f

6'

icT-

e'WpATTET.l

W^y

FOR SINK STRIP

4'

5'

PATTERN FOft/ RETURN R E

.

315.

l-iK.

true profile for the side of the bracket on the lino Parallel in as follows: )M, ilraw any line, as

cet-il

(

angles to

()M, and from the

variotis intersections

in

distances to points

mnnbcred

V

Z',

ti

to

line

1.')

VZ in

1.')'

Z'

and <JK, proat right

on the same, dniw

and i>lace them on similarly and every instance from the line to 1.'.' and 1")" to 10", as shown.

an
lines nteasnring in I'ach

thus obtaining the points •'»' line through the points thus cibtained.

10'

).M

V Z'; and

V

Trace a ?''.>'

(

Z' as shown. Now, n»easuring the normal prolile. take the various

lines indefinitely, crossing to the line

each instance from the

PAT T CRN FOR C

be the pattern

Then

will

V

0'

for the side of the raking bracket,

tf
SHEET METAL \WRK

232

and

10' 10" 15" 15'

lines

K L and H J in the front.

the pattern

For the pattern right angles to

nonnal

the sink strip shown by the

for

for the face strip B,

draw any Hne,

as A^ B', at

G M, upon which shown

profile, as

place the stretchout of 10 15 in the from 10 to 15 on A^ B^ Through these

at right angles to A' B^ draw lines as shown, which intersect points, and J. with lines drawn from similar intersections on the lines

H

FG

through points thus obtained as shown by F° which will be the pattern for the face B, B.

Trace a

line

G° H°

J°,

For the pattern for the sink-face C, draw C^ D^ at right angles to GM, upon which place the stretchout of 10' 15' in the normal profile

shown from 10' to 15' on C^ DS through which, D\ draw lines, which intersect by lines drawn from similar intersections

as

at right angles to

C*

on

K L and H J.

Trace a line through

the points so obtained as J° K° L° H°, which is the pattern for the sinkface C.

The the face

will

be developed

by drawing

piece,

EO

pattern for the cap

A

the line E^ F'.

D

and

in

one

at right angles to

At right angles

Fig. 316.

Fig. 317.

and through the figures, draw lines, which intersect with lines drawn at right angles to EO from similarly numbered intersections on REF and NOP. A line traced through the points thus obtained, as shown by R° E° F° and N° 0° P° will be the pattern for D and A. For the patterns for the cap returns R E and O P, draw any line to E' F',

at right angles to 1 1 in the

normal

place the stretchouts of the profiles R each space separately onto the line 0^'

G'

1^

and

W,

6"^

which

F.

Through

intersect

by

profile, as

these points lines

drawn

204

H^

G',

upon which

E and O P, being careful to carry H^ GS as shown respectively by draw

lines at right angles to

at right angles to

1

1

from

;iii:i:i-

siiuilar

mktal work Trace

imnihers in \V ami X.

Then

uhtaiiuij.

R

of the (a)),

will

K; while

N' .1'

(

233

lines through the tlius jx)iiit.s he the pattern for the lower return L' K' will he the pattern for tl»e up|>er re-

U'

)'

M'

S'

IM J.

turn.

In

31G

Fig.

is

shown

a perspective view of a gutter or eave-

an exterior angle, for wliich an outside miter would he reIt is iiiitnaterial what t|uircd. shape the gutter has, the nieth<«I of the for miter is the same. the In Fig. 317 let 19 nl)taiMing pattern trough at

the section of the eave-trough with a l)eaer of spaces, as shown liy the small divisions d to 1 to 9

10 represent at

ah

edge an e<^|ual

Draw any

to 10.

A

r;

vertical

out of the gutter as .shown ed lar

line,

as

ujM>n which place the stretch-

r..

letters

l)v

sinn-

»

and nund)ers on

A

B,

through which, at right angles to .V H, draw lines, which intersect l)V

FiK. 31.s •'IPS V

drawn

line

pjtrallel

to

1-iK. M'.).

AB

from similar points

thntugh the points thus ohtained.

in the section.

Then

will ('

U KF

pattern for the outside angle shown in Fig. 31(1. If a pattern is refpiired for an interior or inside angle, as

is

Trace be the

shown

CI) and F K

in the necessary only to extend the lines .1 I) 111. a> Tlienwill pattern in Fig. 317, and ilraw any vertical line, lie 3 shown in IS. II the for the inside !•' Fig. angle pattern in Fig. 31S,

it is

In Fig. 319 are .shown a plan and elevation of a moulding which In other words, A B has more pn>jection on the fnuit than on the side. is to l>e represents the j)lan of a hriek pier, around which a ct)rnice constructed. The |>rnjcction of the given profile is itjual to C, the The projection of the fn»nt profile in eh-vation heing .shown l»y ('.

in

plan

is

also c«pml to C,

«.s

.shown hy

C.

The

pntjecfion of the

left

side of the cornice should he only as much as is shown l>y I) in plan. This re«|uires a change of profile thn)Ugh I), as shown hy D'. I'o ob-

2UQ

SHEET METAL WORK

234

tain this true profile

Fig. 320, in

which, in

which

its

and the various

patterns, proceed as

shown

in

A B C D represents the plan view of the wall, against E is placed and divided into the 1 to 12. figures by Through 1 2, parLocate at pleasure the projection of the re-

proper position, the profile

equal spaces, as shown allel to C D, draw F.

G

B H, and draw H G parallel to B C, intersecting F G Draw the miter-line in plan, G C. From the various divisions

turn mould, as at

G.

in the profile

CG

E, draw lines parallel to

as shown.

nitely, as

shown.

From

C D,

intersecting the miter-line

these intersections, erect vertical lines indefi-

Parallel to these lines erect the line

K J, upon which

place a duplicate of the profile E, with the various divisions on same, as

shown by E^

Through

these divisions

266

draw

horizontal lines

in-

;'?'-

FRONT AND BEAK VIEWS OK HKSIDKNCK OK HENRY STEINBRENNER. BKl IKIDWKK AVENUE. CLEVELAND, OHIO WnltonMiii Ilrli'k l'
Kxl«rl<>r

\

S.

Iiiirlili-r.

l« M<<';iu
Anhltr.

!•<.

<

lirlik. M.t
llHl»orlftl" H«Hl TUn.

IrvrUnd. Ohio. Akron. Ohio, linnts IVtrrml wiih

I

SHEErr

METAL WoliK

miinl)eri'
tersectioivs

Tiacr a

to 12'.

1

line

tliroiifjli

235

as

shown by

these points,

tlie in-

'Hien

will

tlie true section or profile t)n II H in plan. For the pattern for the return II (1 (' B in plan, extend the line which place the stretchout of the profile F', l>eing A, as B M,

F' be

B

upon

measure each space separately (as they are unwjual), as B. shown by figures 1' to 12' on line this ami through the figures,
careful to

M

which intersect by lines drawn C G. Trace a j)oints on line

thn)Ugh the points

T hen

thus obtaine
from similar

at right angles to II (j

G»

II'

„

C

TRUE PROFILE

.

THROUGH

B' be the

1" ,

pattern

for the

7' IN

plan

return

mould.

The face

pattern for the

GCDF

mould

f)btained

is

taking

by

a

stretchout of the profile E and placing it on the

j<

—f^^

'

' "' .

^'j ^

liK. .;-•.

FiR. .321.

vertical

P

line

right angles to

shown l>y similar figures. thn)Ugh which, at draw lines intersecting similarly numberi^l lines

as

(),

1' ( ),

previously extended from intersections.

Then

will

(' 1

G

in j)lan.

B'C

12

b«'

Trace- a

lin«'

through these

the miter paltmi for the face

mould. Ill til

I'ig.

'i2I is

a chann'cr.

shown a

pers|)ective

view of a gore

Thia presents a pniblein often arising

ildT

pie<-e .\ joineil in

ornamental

SHEET METAL WORK

236

sheet-metal work, the development of which is given in Fig. 322. A B C show the elevation of the corner on which a gore piece

D

H

7'

E

quired. a section through profile 1 7

in plan

X I,

GH

a section through C D, and E F projected from the elevation as shown.

is

all

Let is

reis

The

can be drawn at pleasure, and at once becomes the pattern Now divide the profile 1 7 into an equal number of

for the sides.

spaces as shown, from which drop vertical lines onto the side 7' E shown from 1' to 7'. From these points draw lines parallel to F G, intersecting the opposite side and crossing the line 7' 1"

in plan, as

drawn

is

(which

from T)

at

right

at I" 2" 3" 4"

C

5''

to F G Draw any

angles 6".

K

line parallel to D, as J, upon place all the intersections contained

which

on

7'

K

J. plan, as shown by 1° to 7° on From these points erect perpendicular lines, which intersect by lines drawn from simi-

\" in

PATTERN FOR GORE

numbered

points in elevation parallel Through the points thus obtained Then will 1^ to 7^ be the true trace a line.

larly

C

to

D.

Fig. 323.

profile

on

7' 1" in plan.

For the pattern for the gore, draw any vertical line, as A B in Fig in Fig. 322, 323, upon which place the stretchout of the profile F At right angles to AB, as shown by similar figures on A B in Fig. 323. and through the figures, draw lines as shown. Now, measuring in

V

each instance from the line

plan in Fig. 322, take

7' \" in

the various distances to points

1'

to 7',

and place them

Fig. 323 on similarly numbered lines, measuring in each instance from the line A B, thus locating the points in

F

G

by

FG

7

is

arises in cornice

principles

any

line

7'.

In Fig. 324

shown a face view

work.

No

matter

which are explained for

size or shape.

shown

Fig. 324.

through the points thus obtained. Then will be the pattern for the gore shown in plan in Fig. 322

Trace a

shown.

in Fig. 325.

AB CDEF

G.

of a six-pointed star,

which often

how many its

points the star has, the development are applicable to

Triangulation is employed in this problem, as First draw the half-outline of the star, as shown by parallel to the line AG, draw JH of Draw the section of the star on A G in plan,

Above and

similar length, as shown.

268

<\]VVr MirrAL \V(jUK as

1

<

K

shown by J

initer-lincs

nulius anil

I

>

1,

as center,

I

K into plan a.s shown at I, and tlraw tlie K I. an
I'n>jeft

I,

necessan,' that

is

it

I.

II.

li I, ('

!n7

1

erect a line cutting J II in section at h.

Draw

a line from h to

on

true Itiigth

For the

shown as

K

[lilt

tern,

Fij;. 32(5.

is

the

proceed

as

Draw any

K II

II, e<|ual in len<;th to

line,

in Fij^.

Then, using K h as ratlins and Fig. 32G as center, describe the

32o.

K

in

K, whicii

F.

I

in

arc b

h,

an arc

which (J (r

intersect at a

FG

an(i with

in plan in

Draw

railius.

and

(i

l»v

struck fnini II as center

K

to a to II to a to

of

tlie

star of

as

32.")

Fig.

from

lines in Fig. 32(1

K, which will he the pattern which G are retjuired.

^Mien l)ending the points on the stay or nuide.

i)rofile

To

so that

we may know

obtain this

.stay,

draw

secting J II at

r.

From

c

PATTERN FOR ^CORNER

.*>et

from H after

vertical line

off to

necessar\- to

have a

B

in Fig.

siiould

325 a

he

line

and

drop a

(!'.

it is

fn>m which point, at right angles to c d as radius, strike an arc inter-

c,

I'.sing c as center,

c d.

UK,

jM)ints

what angle the hend

erect fi-om the corner

intersecting the base-line J II at

J K,

line

at

one of the

for

/

(/'

W

to B',

which the

meeting A () in j)lan at / H, and draw a line

e<|ual to

which

j)attern

is

in

the true

Fig. 32()

j)i\)file

is

to

be

the stay in Fig. 32.') has been correctly develo|)ed, theiw/' B' or (/' B uuisti><|ual

bent.

!

ii

If

in Fig. 32ti

on both

In Fig. 327

is

sides.

shown

a

finishe«l elevation

of u hippeil roof, on tlie four corners of which FiK. :V2(). a hip ridge .\ A butts against the uj)per base B an
tnie profile of this hip ridge, together with the top and lower cuts lower heads, proceed as .shown in Fig. 32X,

nnci the |)attenis for the

where the

front elevation has l)een omitted, this not being ne<'essar\',

as only the part plan and diagonal elevation are

200

letpiiretl.

First

draw

SHEET METAL WORK

238

D

A

BC E the part plan as shown by line F C in a horizontal position; and lines

FA

C B and

and

between

F

A, placing the hip or diagonal the distances between the

make

D equal,

F E and C

because the roof

has equal pitch all around. (The same principles, howAbove ever, would be used if the roofs had unequal pitches.) in this case

the plan,

draw the

G H.

From

F

C

and

line

the points

in plan, erect

F G and C I, extending C I to C^ so

the lines

that I

C will

be the

re-

quired height of the roof above I at the point

G

C

^

-FRONT ELEVATION

in plan.

^^'^^^

^

*»

Draw a line CS and from

C* draw a horizontal and vertical line indefinitely,

Then

as shown.

roof

on

FC

will

G

I

The next step

is

to obtain a true section of th? angle of the roof at

right angles to the hip line at right angles to

F A and F E

FC

From

c.

intersecting

G C^ at d.

F

G C* in elevation.

c,

any Extend a b

until

at right angles to

Take

C, measuring from

This

line, as a

in plan,

as shown.

elevation at

the line

C^ be a true section on the line of the

in plan.

done by drawing

intersecting the lines

cuts the base-line

it

G I in

G

the distance c i to d'.

b,

is

CS draw a line, as c d, d, and place it in plan on

Draw

a line from a to

d' to h,

the true angle desired. On this angle, construct the desired of the as shown shape hip ridge by J, each half of which divide into as shown the As the line C^ repequal spaces, figures 1 to 6 to 1. by

which

is

G

resents the line of the roof,

and as the point d'

in plan in the true angle

also represents that line, then take a tracing of the profile J with the various points of intersection on same, together with the true angle a d' b, and place it in the elevation as shown J^ and a' d" b\

by

careful to place the point d"

G C^

From

on the

G

CS making

being

a' h' parallel to

the various points of intersection in the profile J, draw F C, intersecting B C and F at points from 1 to 6,

A

lines parallel to

As both sides of the profile J are symmetrical, draw lines through one-half.

as shown.

only to

line

270

it is

necessary

SI I Hi: r

III

similar till'

thr.)ii;^'li

at

riL'lit

iiiaiiiii-r,

3

5

6

FC

in pli'.n

.1',

2:j9

G C,

draw lines* drawn numbered j>oints on A F

mi elevation, purallel to

various intersections in

antrles to

w 214

MK'l'AL WOltK

wliieli intersect

from similarly

l)y lines

34 12 5

PATTERN FOR LOWER HETAD

FiK. 32S.

and Br.

K

I

.

"^Prace a line tliroii^di the points tlins ol)(aine«l.

lie (In- iiiitcr-line at

I'or tlie |)atlern,

the iMittotn, and

draw any

line,

271

ils

Then

will

M N the miter-line at the top. O

P, at right an^^les to (»

C,

SHEET

240

^WRK

ISIETAL

upon which place the stretchout of J in plan or J' in elevation, as shown by the figures 1 to 6 to 1 on O P; and through these numbered points, at right angles to O P, draw lines, which intersect by lines drawn at from similar intersections in the lower miter-line right angles to G K L and upper miter-line N M. Trace a line through the thus

O

Then will

obtained.

In practice it or the bottom top

R S T U be the desired to obtain

is

points

pattern.

one miter-cut

necessary only —and use the reverse for the opposite

words,

In other

side.

U T is that part falling out of R S, the same as R U

—either the

S

is

that part

The upper miter-cut butts against Fig. 327; while the lower cut requires a flat head, as shown at C. obtain this flat head, extend the line I in Fig. 328, as I W, which cuts away from

T.

G

which place twice the amount of spaces contained on the

B in To upon

AF

line

in

— 5, 4, 1, 2, as shown similar by figures on either side of line V W. From these divisions erect vertical lines, Avhich by lines drawn parallel to V W from similarly numl)ered

plan, as 6, 3

6 on the intersect

intersections in the miter-line

K L G. A line traced through the points

shown by

thus obtained, as

X Y Z,

will

be the

pattern for the heads. ^\Tiere a hip ridge quired to miter with the

is re-

apron

of a deck moulding, as shown in Fig. 329, in which B repre-

Fig. 329.

A

A

sents the apron of the deck cornice, and the hip ridges mitering at a and a, a slightly different process from that described in the preceding problem is used. In this case the elevation of the

part

mansard roof must

K

first

be drawn as shown

Let

in Fig. 330.

ABC

represent the part elevation of the mansard, the section of the

deck moulding and apron being shown by allel to

B

C.

D B E.

Draw E

EX then represents the line of the roof.

In

its

position, at right angles to B C, draw a half-section of the hip as shown F G, which is an exact of B of

by

mould.

Through the corners

of the hip

B C, which intersect by E in the deck cornice. and W,

lines parallel to

from V,

E

reproduction

par-

proper

mould,

the deck

mould at Y and G, draw drawn parallel to B A

lines

Draw

the miter-line

which completes the part elevation of the mansard.

272

X

H I,

SHEET METAL WORK Befort- the patterns can

must he ilrawn.

inaiisanl

B

tical line, iLs

tance

H

('.

CK

B

(tf

'I'hereforc,

H

K

at

[»la«e

Take the

surface of

draw the horizontal

jirojection

J to

(' in

tlie

(Fig. 330), tlrop a verJ. Now take the dis-

vertical line in Fig. li^U,

these two points

Thn)Ugh

as shown.

on a

it


fn)m

J, intersecting the line ('

and

(',

a

l»r (»ljtaiiii*
?A\

Fig. 330,

a.s

line.s

shown hv

B \ and

and place

it

as

PART ELEVATION OF

MANSARD ROOF

PART PLAN

TRUE SECTION

ON OP' R'

Via.

shown will

fnini

A B As

K

l)o

Fig. 331. an«l

)ividc l)ofh

the angl.

A

B

\'

W

F, an
shown l>y |)lace into the same mnnher

and

(

F\

a line fn.ni

B

.\ (

'.

<"

K

(' to

B.

Theix

in Fig. 3.30.

are similar, take a tracing

XU.

respectively in Fig. Bistvt of c«pial spaces, as sh«)wn. a and /<. and, u.sing these a.H tx-nlers. estahlishing hy it a,s

'

I'.

draw

the devclo|)ed surface of

l)oth the |)rofiles

of cither, 1

('

C to C in

:5:»n

|) an.l

273

1 >'

SHEET METAL WORK

242

draw d B, which represents in the and D\ draw Unes parallel Through points to their respective moulds, as shown, intersecting the miter-line B d by describing

arcs intersecting at c; then

D

the miter-hne.

and the base-line C C^ For the pattern for the

hip, draw any line, as E F, at right angles twice the stretchout of D, as shown by the which C, upon place divisions 6 to 1 to 6 on EF. Through these divisions draw lines at

to

B

PATTERN FOR --.HIP

RIDGE

D'

I

hP

•^ ^^^ 5 6

DEVELOPED ROOF

SURFACE OF

MANSARD

K Fig. 331.

right angles to

right angles to

E F, intersecting similarly numbered lines drawn at B C from the divisions on B and C C^ Trace a line (Z

through the points thus obtained. for the hip ridge.

When

bending

Then

this ridge in the

will

machine,

G H J L be the pattern it is

necessary to

know

what angle the line 1 in the pattern will be bent. A true section must be obtained at right angles to the line of hip, for which proceed as shown in Fig. 330. Directly in line with the elevation, construct a at

part plan the angle

L M N O, through which, at an angle of 45 degrees (because L O N is a right angle), draw the hip line O M. Establish at

O

M, from which erect the vertical line pleasure any point, as P^ on into the elevation crossing the base-line C at P and the ridge-line

K

CB

at

shown.

O

M in plan, draw

O^ P^, equal to O PS as Extend P^ P^ as P^ R^ which make equal to PR in elevation.

R.

Parallel to

274

mktat. ^voRK

;iii:i:r

1

)r;iu

Ol"

iM-iii

liii.

;i

ill

j)laii.

LO

hv, cutting

(

P- at

f',

ON

at d.

With d as

e. )'

and

O' 1"

interset'ts

d

'I'lR-nO'

ll'toO'.

Thnnitfli any

center,

|>«)int,

ami

at h

OM at

c

is

ri;,'lit

(JM, «Jraw Kxteml b c until it

aii^'les to

respettively.

r".

1

at right angles to

)raw a

lii'

sents the true section of the hip after

'XM

rt-prfseiiLsa tme.sertioiion

a, at

Fntin d, at right angles to ()' K', ilraw tlie line and dr as radius, draw the arc r «', intersecting

fn)m which point,

line intersecting

It' 1*^

sls

243

fnjm b

>

OM

to

i-"

in plan,

to c,

draw a

whidi repre-

which the pattern shown

in Fig.

fornietl.

The

D

H in Fig. '.i'M) is ohtaintHJ in the pattern for die deck mould as tlie s(|uare miter shown in Fig. 277; while the pattern for

same way

the apron D' in Fig. 331

shown hv

;i

In Fig. 332

is

riilge

tills

view

ABC

II

is

same

the

as the one-half patteni of

tlie

hip

0.

1

.shown a front elevation of an eve-l)n)W dormer.

In

represents the front view of the dormer, the arcs being

Fig. 332.

struck from the center points I), K. and F. line II J in elevation is shown at the right; L

donner, indicated elevation hy

(

)

section taken on the

shows the roof of the

hy X; while the louvers are shown

in the section

P and

.\

M

in section l>y

in

HT.

Ill I'ig. 333 is .shown how to ol>taiM the various patterns for the AI'ii tlu' half-elevation of the various j)arts of the doniicr. repre.sents is the line of the donner, and KF(1 a side view, of which donner^

FO

KF

that of the n)of,

the

donner

The

is

fn)nt

and side views

as follows:

spaces, as figures oil

which

re(|uired to miter.

positions, the first step I'roc-ee
line of the pitched n)of against

and (IF the

is

lu-ing j)lace«l in dicir pii>pcr relative

to obtain a true se<'tion at right angles io

Divide the curve

to shown from A H, draw liiu-s I

[).

.\

to

]\ int<»

\\ right angles to

intersecting

87a

K

(i in

a

number

.\ (',

.•*idc

and

FF.

of etpial from the

view as .shown.

SHEET METAL WORK

244

From

these intersections,

the roof-line

J

'

GF

at P,

ONE HALF TRUE PROFILE ON LINE E-H IN SIDEVIEW

and

2^ 3^

parallel to

etc.

EF, draw lines intersecting EF, and from the point

Parallel to

9

9

6 5 4 3 2 ONE HALF PATTERN FOR SHAPE OF 7

OPENING

IN

_9 1

V

ROOr

Fig. 333.

G, draw any line indefinitely, as G H. At right angles to EF, and from the point E, draw the line EH, intersecting lines previously drawn,

276

METAL WORK

Slll.l/l

at

2',

1',

;>',

a>

III.,

extended as

At

at right

angh's to

A H. 'i'race Then K L.M.I

a

tluTe«iii,

take a dupHcato of the line EH. with ami placi- it on the center hnc AC

KJ, and from the

fif^urcs 1", 2^, 3*,

whieli intersei-t with those of simihir

numbers drawn

K.T.

draw hues,

ete.,

Now

^iiiiu n.

various iiitersectious

tlif

245

ri<jht an<,des to

CH, and from

hue through

will

simihirly niunhered points on the cur\'e

tlie

points of intersection thus obtained. in side |»rofile on the line K

H

be one-half the true

view, from which the stretchout will be obtained in the development of the pattern.

For the to

KF

for the roof of the

j)attern

in sitle

one-half the tnie profile

X

dormer, draw

at right angles

upon which place the stretchout of on the line KII as shown by the snuill figures

view the line

( ),

Then, at right angles to X O, and through the figures, which intersect with those of similar numl)ers drawn at

'2\ 3*, etc.

r.

draw

lines,

right angles to

through the

EF

])oints

from intersections on ECi and GF.

Then

thus obtained.

will

PKST

Trace a

line

represent one-

half the pattern for the roof. To obtain the jiattern for the shape of the opening to be cut into

the to

ro(»f,

transfer the line CIF, with the various intersections thereon,

vertical line, as

any

UV,

as

shown

by the

figures

.similar

manner, transfer the

1',

2«,

3',

etc.

In

HALP PATTERN FOR LOUVRE *'4

line 7

C'H in fn)nt view, with the various intersections

on same,

ZW, drawn

at right angles to I'V,

to

the

line

shown by the figures 1, 2, 3, etc. At right angles to \'\', and fi-om tile figures, draw lines, which inas

tersect with

drawn

bers

Through

Then to

be

those of similar at

right

num-

angles to Y'A.

these points, trace a line. LX^'Z l>r die half-pattern for the shape of the o|>ening into the main nnif.

will ctit

the |)uttern for the ventilating slats or louvers, should thev In thi.s iii|uircd in the donner. |)ro(rrd as shown in Fig. 331. ( A is H a of tlie inside shown in figure, Fig. X^i. repniduction opening I-'or

111-

Let

1,

uill

be

2, 3,

•},

.')

in Fig. .331 represi-nl the srrtions of the louvers

in tliis plnci.*
opening.

As

which

the mellutds of obtaining the put-

27-J

SHEET METAL WORK

246

No. 4

terns for all louvers are alike, the pattern for louver trate the principles

employed.

Number

will illus-

the various bends of louver

No. 4 as shown by points 6, 7, 8, and 9. At right angles to A B, and from these points, draw lines intersecting the curve A C as 6^ 7^ 4\ 8^ and 9^ On B A extended as E D, place the stretchout of louver No. 4 Since the miter-line AC is a curve, as shown by the figures on ED. be necessary to introduce intermediate points between 7 and 8 In this instance the point marked 4 has been added. it

will

of the profile, in order to obtain this curve in the pattern.

Now, at right angles to DE, and through the figures, draw lines, which intersect with those of similar numbers, drawn parallel to AB from intersections 6' to 9*

A line

on the curve AC.

traced through the points thus obtained, as FKJH, will

be the half-pattern No. 4. The

for louver

for the face of

pattern

the dormer onto the

is

pricked

metal

direct

from the front view Fig. 333,

B C

is

in

which

in

A8

the half-pattern. out the

In laying ^^§-

that each side of the in Fig. 335, in

a bay

which

patterns for bay window work, it often happens

"^'^•'^-

window has an unequal

DEE shows an

projection, as is shown elevation of an octagonal base of

window having unequal

All that part of the projections. bay obtained by the method shown in Fig. 290, while the finish of the bay shown by ABC in Fig. 335 will be treated here.

above the

line

AB

is

In some cases the lower ball section through

drawn

A B.

It will

C

is

a half-spun ball.

be noticed that the

respectively at right angles to ab, be, it

and

A^ B^ F^

is

a true

lines

Ca, Cc, and Cd,

cd, are

each of different

necessary to obtain a true profile

lengths, thereby maldng of these lines, before the patterns can be obtained. explained in connection with Fig. 336, in which

This

and plan are required as both

First

on each

is

clearly

only a half-elevation

sides are symmetrical.

278

draw the

SHEET METAL WollK

247

hase of

center line

lialf-elevution of the

Imv,

unfiles to All •Iraw the wall line

in

a-s

Ml, oi\ whicli ilraw the shown hv (T>E. At ri;,'ht

FK; and

plan, as

elevation, «lra\v the

corners

II

ami

I

in its

proper position

(lesirelan,

draw the

iiiiter-lines

as

in relation to the line

shown hy (lilM.

tlie

CD in

From

the

.Vs

DF

IIF and IF us shown.

'

'I'L'

7

6

j^

4

2

3

1

HALT PATTCRN FOR

R

3 FiR.

:vM\.

F(l in |)lan. tlien divi«le the profile represents the^iven profile thronj,'h to 1.? of uumiIkt 1)1'' into an spaces as shown l»y the lij^ures eipial I

Fmrn in

these

plan,

line's

draw

a.s

j)oiiits

shown.

drop

vertical lines intersecting; the initer-line Fll

From

these intersections, parallel to III. tlraw

intersecting' the miter-lines IF.

lines

intersecting'

points of intersection in and left as .shown.

fn>m which points, parallel

the «ciitcr line I'l-,

I'M

draw hori/onlid

270

Thnm^h

to

1.1.

the variiuis

lines indelinitcly ri^'ht

SHEET METAL WORK

248

If for

any reason

it is

desired to

show the

elevation of the miter-

plan (it not being necessaiy in the development of the patthen erect vertical lines from the various intersections on FI, tern), To avoid a confusion in the intersecting similar lines in elevation.

line

FI

in

drawing, these lines have not been shown. Trace a line through D' 13, which is the desired miterpoints thus obtained, as shown by line in elevation.

The and IJ

next step

is

to obtain the true profile at right angles to

To obtain the true profile through No.

in plan.

HI

3 in plan, take

a tracing of J F, with the various intersections thereon, and place it on a line drawn parallel to CD in elevation, as J^ F^ with the intersections

From

shown.

these intersections, at right angles to J' erect lines intersecting similar lines drawn through the profile 1 to 13, as

F^

DE

elevation.

by

1'

Trace a

to 13',

which represents the true

right angles to

rious lines 13, as

IH

drawn

in

through the points thus obtained, as shown

line

in plan,

draw any

parallel to

IH

profile for part 3 in plan.

line, as

ML,

At

and extend the va-

until they intersect

LM at points

1 to

shown.

Take a

tracing of

LM,

with the various points of intersection,

and place it on any horizontal line, as L^ MS as shown by the figures 1 to 13, from which, at right angles to L^ M\ erect vertical lines inter-

numbered horizontal

lines drawn through the profile Then will through the points thus obtained. 1"— 13" be the true profile through No. 2 in plan at right angles to HI.

secting similarly

DE.

Trace a

line

For the pattern

for

No.

1

in plan, extend the line

FK,

as

NO, upon

which place the stretchout of the profile DE as shown by the figures 1 to 13 on NO. At right angles to NO, and from the figures, draw lines, which intersect with lines (partly shown) drawn parallel to FG from similar intersections on the miter-line FH. the points thus obtained; then will

IP

Trace a

line

through

13 be the pattern for part

1

in plan.

H

T

At right angles to I, draw any line, as U, upon which place the stretchout of profile No. 2, being careful to measure each space separately, as they are all unequal, as shown by the small figures 1" to 13" on TU. Through these figures, at right angles to TU, draw lines as shown, which intersect by lines (not shown in the drawing) drawn at right angles to I

H from similar points on the miter-lines HF and FI.

280

SH KKT MK'IAL a line thruu^li the points thus the pattern for part 2 in plan.

'I'ruc-e

WOHK

249

Then

uhtuiiic*)!.

will

\'

\V

X

l>e

f»»r part 3 in j>lan, extend the center line A H of the true pmfile for ujK)n which place the stretchout hein^ careful to measure each space separately, us shown by tlie

F'or the half-pattern

in .'i,

H K,

plan as

li^'iires

r

on BR.

to 13'

At

ri^'ht an^'les to

H K draw

lines throuj^h

the fi<;ures. which intersect hy lines drawn at ri^'ht angles to .1 I fn»in A line trace*! similar points of intersection on tlie miter-line V I. tlironj,'h

points thus obtaine
T S

13', will

he the half-pattern

for part 3.

DEVELOPMEINT OF BLANKS TOR CLR\LD MULLUlNuS Our it

first

attention will he <jiven to the

hcinfj necessary that

we know

methods of construction,

the methods of construction before

For examj)le, in Fi};. 337 is a part elevation laiil out. donner window, with a semicircular top whose profile ha.s an ogee, If this job were undertaken by a finn who had no fillet, and cove. the blank can be

of a

moulding machine, as is the case in many of the smaller shops, mould would have to be made by hand. The metluul of c-onstruction in this case woulil then be as shown in Fig. 33S,

circular

the

which shows an enlarged section through a b in Fig. Thus the strips a, b, and r in Fig. 33S would be 337.

and would be nothing more of metal, while d d' wovild be an

cut to the retiuired size,

than straight strips angle, tlie lower side

and turned /.

and

It

to

would

d'

a.

c^

\

// X(-^ /

^^KP

s^^

being notchetl with the shears

The face strips r, the re<juired circle. (»f circles to correspond re|)resent arcs

to their various

diameters obtained from the

full-size
Xi7.

sink strips would all be sohh-rcd togetiicr, and fonn a succession of scpuire angles, as.shown. in whit'h thcogfc, as shown bv y, and the cove, as shown by m, wttuld lie elevaiiiiii.

'!1ic>c

face and

(

In obtaining the patterns for the blanks hammered by hand, the averaged lines would be drawn as shown by h I for the ogee and fitted.

no

for the cove.

The method

or principles of averaging these and

other moulds will be explained as we j»rocee«l. In Fig. 330 is .shown the same mould as in

th«" previous figure, a dilTerent mt-thod of <-«»nstruction being employnl fn»m the«»ne nuide bv hand and the onehannnered ui) bv nuichine. In nutchine work this

281

SHEET METAL WORK

250

mould can be hammered sheets in use,

if

one piece, 8

in

such length

is

feet long or of the length of the

required, the

machine taking

Fig. 339.

Fig. 338.

mould from

A

The

to B.

pattern for

by drawing a line as shown by plained

more

fully as

in the full

we

CD.

work

of this kind

This method

is

averaged be ex-

will also

proceed.

SHOP TOOLS EMPLOVED When

working any circular mould by hand, all that is requirerl in the way of tools is various-sized raising and stretching hammers, mandrel including raising blocks square stake, blow-horn stake, and

made

of

wood or

A

lead.

first-rate

knowledge must be employed

of these small tools. In by the mechanic in the handling and working a thoroughly up-to-date shop will be found what are known as "curved

moulding" machines, which can be operated by foot or power, and which have the advantage over hand operation of saving time and labor, and also turning out first-class work, as all seams are avoided.

PRINCIPLES EMPLOYED FOR OBTAINING APPROXIMATE BLANKS FOR CURVED MOULDINGS HAMMERED BY HAND

The same

governing principles underlying

as every sheet-metal

worker uses

all

such operations are the

in the laying out of the simple

In other words, one who understands how to patterns in flaring ware. of a cone understands the principles out the for a frustum pattern lay of developing the blanks for curved mouldings. The principles will

be described

Our

in detail in

what

follows.

that of obtaining a blank for a plain flare, problem shown in Fig. 340. First draw the center line B, and construct the half-elevation of the mould, as C E F. Extend E until it interfirst

is

A

D

282

D

PLAN OF RESIDENCE OF DR. FOLTZ. CHESTNUT HILL. (imirtfxT.

tVamon, Arohltoct,

InlTliir WiiiMlwork UTrp«t<-<1 In Dulrh Hlylr. of ! RrM>rii.

IIuvp

II

tliini'i

nn'l

l'il!i'»0

i

ADKLI'HI

A.

PA.

Pu

tniit

In l.lvlinj Knoin itrnl Soi n utnl Kliiliti)'.) Ill rincpn nllh lju,',t!i 'hi- Imtih siyliv Kxiorlor \'li« Minwn

Wixnl 1

I'HI L

rbtlntlFltiliU.

•

III

I

Vlllti.

•«

MI.IM. Wol'.K

SllEK'l

st'cts

as II (,'

the center line

II. 1

AB

at

Ai ri^ht angles

( J.

to

AH

fnun any

[xiint,

'

draw

11

to I't^niA

1

(

as shown.

1),

I'sing II

as radius, descrihe the <|uarter-circle

l).

Ofol

Divide

I

7,

7 into e(|ual spaces, as shown.

1

as center,

which

is

Now usinj;

and with

a section on (i as center,

with radii et|ual to (J E and < D, describe the arcs 1) 7' and K E°. Kn)in any point, as 1', draw the radial line 1' ( I, intersecting the inner i

arc at

Take

K"^.

a stretcluuit


the (piarter-section; place

Fir. 310.

from r to lit

\y.

Then

rc<|nireil in

In

If

one

this

hannner.

I'

I

line

>ivide tin-

.\

nioiihl

the hiank innst

mm/ion

H;

cove

inner arc

7'

Ik-

this lurr so that

whose

pn)(ile contains a (^>ve.

stretclu-d with the stretching tlir

.slmlnil will piuj

ht Ihi- riilr fnr (ihtniiiini/ imltrru.s fnr .itrrlrlud unniltit.

nnrcr

:u\.

line fn)m7'iii (i, iiilcrseetin;,' the

shown acnrvnl

|)rolil<>.

W'r

shown

piece, join four pii-crs.

Fi;;. ."Ml is

To work

as

V° he the .|uartcr-pattern for the Hare 1) K tlw pattern is re<|iiin'd in two halves, join (wo pieces;

will 1-?

in elevation. if

I'Hi.

and ilraw a

7';

it

als«» tin- lialf-elrvalion F,

1) into

an

«><|nal

of the moulding, as

lunnhcr of

2HM

First

spiuf.s,

h.s

attrnhan

draw the

(1) K

shown

F.

fn)ni

SHEET METAL WORK

252

a to

Through the center

e.

extending

it

until

it

draw a hne

of the cove c

AB

meets the center line

at

parallel to e a,

G, which

is

the center

Take the stretchout of the strike the pattern. point from which to cove c e and c a, and place it as shown by c e' and c a'. \Mien stretche' and a' being hammered toing the flare a' e' c remains stationary, ,

wards

and a

e

intersecting

and

H

1

H

respectively.

1,

drawn

Therefore, from

at right angles to

as radius, describe

the arc

1

7,

a vertical

c erect

A B, at 1.

Using

line

H as center

which divide into equal With G as center,

spaces as shown.

G

and radii equal to describe the arcs e"

Draw

a".

,

Gc, and

V

7',

G

e' ,

and a"

a line from e" to G, inter-

the center and lower arcs at

secting

and

a' e",

Starting from 1', lay off the stretchout of the quarter-section as 1'

a".

shown from HALF 'ELEVATION .^

1'

to 7'.

Through

7'

draw

a line towards G, intersecting the inner arc at a"; and, extending the line

,

upward, intersect the outer arc at e". will a" e" e" a" be the quarter-

Then

D

in elevation. pattern for the cove E If the quarter-round were re-

NO

PATTCRN'

E D, then, would require to

fjuired in place of the

as this quarter-round

I

s

cove

be raised, the rule given in the former Instruction Paper on Sheet Metal

Fig. 342.

Work would be

of raised mouldings. applied to all cases In In Fig. 342 is shown a curved mould whose profile is an ogee. this case as in the preceding, draw the center line and half-elevation, and divide the ogee into a number of equal parts, as shown from a to h.

Through the flaring portion of the ogee, as c e, draw a line, extending it upward and downward until it intersects the center line A B at G. Take the stretchouts from a to c and from c ioh and place them reon the line h' G. Then, in workspectively from c to a' and from e to h' from c to e remains stationarj^; of the flare the that ing ogee, portion the part from

from

e to h' will

c to a' will

be stretched

be raised

to

form

to

c a.

form

e

h while that part shown

ary flare, as d, erect a line meeting the line

284

;

From any point in

H

1,

the station-

drawn

at right

SlIKirr

A

angles to till'

a>

l^iii^' II

1.

and

(|iiarti*r->t'(tioii,

tlividt*

the

(

<«'iit»T

saiiH-

ami

into

253

II

1

a.-.

ra
.s|iacfs,

i-iiiial

jts

.shown.

II.S

I

at

.•^tartiiij;

lay off the .stretchont of the sei-tion

!',

line to

<

Then

he the

It"

for

ItTIl

In

tl

will

when

shown

is

di"-

hea d

a

enij)loyed.

draw the

.\s l)ef«)re, first

^\

center line A' R' and the half-elevation

B C D.

.\

the head takes

j,

for /

same

as for r

(•

the patteni

^

j

ii|)

he

the

then

will

will c,

for r r only

he shown, which can also he use
the

^CLEVATIOfjl

and as the pat-

tern

<

HALF

A|

shown hv

of a circle, as n c c

to

«"

//"

iiow the hlanks are

.\s

1'

Kl).

le (u'ee

inonltlinj;

shown from

(|tiarter-j)at-

Fii;. ;{4;^ is

velojHil

jls

a

liefore de-

as

i,

.serihed.

draw

7'

Through

"'.

(I

WOKK

center anil with radii e<|ual to ( i «', ( J
With

n"

H. at

MKTAI.

'•

/ (

points

which

r

c

p If

.stationary

patter

M

/.

ohtainin;:

,

mid

h f

f/_

t

the

in

the

II

Take

stH'tchoiits of

PATTERN ^.L/

I

>

points ^.

i

Hi.sect

l>

to

(/

tin-

<*

^

;ind 3i:v

KiK and place them as shown from to d' and fnun to r' also take the stretchonts of ({ to and (/ to c, and jihice them fn>m d to r' nnd froni (/ to «•' on /'

to

'

.

I,

t>

;

<•

lines '/.

drawn

parallel

Kxteiid the lines

line erei-t

.V

H'

at

!•'

respectively to ' »

and

c'

V

and

<•'


respectively.

lines intersoctinj; the line

(J

2AS

c

and

«' until

1.

c r

fn>m

|Miints

h

and

ihev intiTsii-t the cvnter

I-'mm

drawn

the at

points

rijjht

/»

angles

nnd to

(/

A'

SHEET METAL WORK

254

and

B', at 14

G

eciual to

G

14 and

G

Using

1 respectively.

as center,

and with

radii

Divide as shown. 1, describe quarter-sections, With to 14. from 8 and 1 to from shown as 7,

both into equal parts, E as center, and with radii equal to

E

c',

E

d,

and

E

e

,

describe the

arcs c" c", d' d', and point on one end, as e", Now arcs atd' and c". inner the to line draw a radial E, intersecting d' at 1 to from of section the 7, and, take the stretchout starting lay e"

From any

e".

,

shown from

off the stretchout as

to

1'

7'.

Through

7'

draw a

line

towards E, intersecting the inner arc at c' and the outer one at e". Then will c" e" e" c" be the quarter-pattern for that part of the

bead shown by

c e, also for

For the

e f, in elevation.

pattern for that part shown by a c, use F* as center; and

with radii equal to

and

Fig. 344.

a" a",

and

h' b',

on the arc

b' b'

out of the

,

F

c" c".

as

8',

From any point

14'.

lines

8 14,

towards

them

until

at c"

outer arc

as

these

Through

F', in-

tersecting the inner arcs at a" o";

extend

b,

lay off the stretch-

quarter-section

shown from 8' to two points draw

F a, F

describe the arcs

c',

and

they intersect the

and

c'.

Then

will

be the desired pattern. In Fig. 344 is shown an illustra-

c" a" a" c"

tion of a

round

finial

which contains

Fig. 345.

in principles of which have already l^een described The ball is made of either horizontal the preceding problems. or vertical sections. In Fig. 345 is shown how the moulds in a finial

moulds, the

A

of this kind are averaged. The method of obtaining the t;i:e length of each pattern piece will be omitted, as this was thoroughly covered in the preceding

side of

problems.

First

draw the center line A B, on finial, as shown by C D E.

which draw the section of the

either

The

blanks for the ball a will be obtained as explained in the Instruction Paper on Sheet Metal Work. The mould b is averaged as shown by the line

e f,

extending same until

representing the stretchout of the

it

intersects the center line at h, e /

mould obtained,

286

as explained in the

MK'IAI,

SIIKK/I'

Slii'ft

papff

i>ri

railii,


In

.Mi-i;il

tlie

Wnrk.

Maiik

2.-..'

siim h as ceiiUT, with

I

//

ami

/

//

e

as

li^.

next iiuHild, c

tilt"

WOUK

c',

a

st'aiii is

localnl in suine as shuwii hy

'

Thfii avera^'e < Ity the line /;', extending same until it meets the center line at k: also averaj^e r' hy the line / m, extending this also until the center line is intersecte«l at ti. Then / and / m the clotted hne.

/

represent respectively the stretchouts of the mould c r', the blanks c° anil c* being struck The m«»uld respectively from the centers k and n. b'

b" also has a

seam, as shown hy the dotted line, the moulds being n and /, which, if exteiule*!, intersect the /> and //. These points are the centers, respectivelv, for

averaged by the lines center line at

r

striking the blanks b°

.v

and

6*.

I'he llaring pieces/

A

is

struck from the

8

with radii e(|ual to .r w and .r r. thus ol)taining the blank d°. to the various rules given in referring By previous pn»blems. the true length of the blanks can be obtaineil.

center

jr,

The to

princi|)lcs used for

almost any form that

in Fig.

:i4(i.

in

which

A and H

that sh(»wn in Fig. .'MT. in

a and

}>

example which

which

example,

in the

case

shown

represent circular leader heads; or in .\

and H show two

stvles of balusters,

.\nother representing the s(|Mar«' to|)s and ba.ses. that of a round litiial. as in Fig. .'Ms, A showing the IumhI

lin i)t)th) is

slips

over the apex of the

l)ouglit. yet in

architc
but one

blanks hanuncrcd bv hand can be applie
will arise, as, for

it

is

is

roof.

While

thesj-

forms

«'an

be

some cases where

a special design is lii-ough.f out bv the nc-cessarv that thcv be made l>v li.ind. cspeciallv when

nipiired.

'I'lu- last that of |tniblem on handwork is shown in Fig. ."MU obtaining the blanks for the bottom of a circular bay. The cunitl moulding \ will be hammerni bv hand or bv nuichine. as will Ik* ex-

2fiT

SHEET METAL WORK

256

while the bottom B is the problem before us. The plained later on, be seen, is the arc of a circle; and, to obtain the various plan, it will

A

B blanks, proceed as shown in Fig. 350, in which on of the bottom of the bay, being a plan view

UK

C

the elevation

is

A C,

showing the

Fig. 347.

curve struck from the center H.

In this case the

bottom of the bay

front view of the

is

given,

and

ABC

taken on the must have the shape indicated by It therefore becomes necessary' to line I J in plan. establish a true section

plan,

from which

on the center

line

S

K

in

.^

to obtain the radii for the blanks or

Fig. 349.

To

patterns.

number

division, at right angles to

wall hne I J at points

equal to

H

center line

6',

shown from

A

to 6'. 3',

shown from

1"

5',

AB

into

any

From

the points of C, drop lines as shown, intersecting the

H 4', H

H

DE

1'

)

Fig. 348.

obtain this true section, divide the curve

of equal parts, as

<

1 to 6.

Then, using H as center, and radii and H 2', draw arcs crossing the to 6".

288

At any convenient point

SHRKT MKTAL WORK op|)«»site tlif

llif

fn»nt elfvatioii ilraw

fniiii

liiu's

tlif

the \ertical line

T

from the point S

spares \'

in

in

any

the

as shown.

vcrlu-ul line,

A H

profile

Now,

plan, take

2o7

a.s

until

inea-surinj; in

T

I

Ivxteml

.

interseet

tiiey

even- in.stunce

the various distances to the nuin-

TRUC SECTION

ON 3- K

.

Kl

I

1'

E Fig. 350.

hered points in plan ami place them upon lines of similar nnmhers, meitsuring in every instance from the line

S

K

T

l'

section.

in

Thus

take

tlie

distance

from the line it as .shown |)Ian, and place T r to K'jthen aj^ain, take the di.stance fn»m S to 2" in plan, an«l j>lace it as shown from the line T \' to in

Proceed

line 2 in .section.

the

in

true

.section

shown, when 1" to line S K in plan. It

making tlie

should

l>c

(»"

in this

manner

V

will

understood

on

Trace a line as

he the true section uu

tin-

method

for

the usual

that

the hottom of hays n)und in plan

niouldinj^ into such parts as can

suming

L'"

until all the |M)ints

have been ohtaineil. to

\

is

lu* licst

M

to diviile the profile nf

rai.si*
or stretchetl.

As-

that this has heen done, take the distance fntm 1" in plan to

11, and place it a.s shown from l" to L in section. draw a vt-rtical line I, M, ;us .shown. Kor the patL, the|>oint tern for the mould I" 2", average a line thmu^h the cMn-nu- points,

the center |>oint

.

From

a.s

shown, and cxtcuil the same

with

N

;ls

center,

and with

r.idii

until

etpial

880

it

meets to

N

2"

I.

M

;ii

and N

N. 1'.

Then. dcscril>e

SHEET METAL WORK

258

The

the blank shown. ing on the arc of the blank.

manner.

1'

length of this blank

1" in plan,

The

Thus P

is

and placing

obtained by measuron the arc 1"

other blanks are obtained in precisely the same the center for the blank 2" 3"; R, for the blank

3" 4"; O, for the blank 4" 5";

The moulds

is

this stretchout

1"

2",

2"

and M, for the blank 5" 3", and 3" 4" will be

6".

raised;

while

the blanks 4" 5" and 5" 6" will be stretched.

APPROXIMATE BLANKS FOR CURVED MOULDINGS HAMMERED BY MACHINE The principles employed in averaging the profile for a moulding be rolled or hammered by machine do not difFer to any material extent from those used in the case of mouldings hammered by hand. Fig. 351 shows the general method of averto

aging the profile of a moulding in determinIt ing the radius of the blank or pattern. will

be seen that

manner, so

AB

drawn

is

in such a

to speak, as to average the in-

D

C required to be distances a and b are equal, as are the distances c and d, and e and /. It is equalities of the profile

made.

^B Fig. 351.

Thus

very difficult to indicate definite rules to be observed in drawing a line of this kind, or, in

other words, in averaging

the profile.

Nothing short of actual experience and intimate knowledge of the material in which the moulding is to be made, will enable the operator

SECTION

Fig. 352.

to decide correctly in all cases.

making very grave

There

is,

however, no danger of

errors in this respect, because the capacity of

the machines in use is such, that, were the pattern less advantageously planned in this particular than it should be, still, by passing it through the dies or rolls an extra time or two, it would be brought to the required shape.

290

SHEi-rr

III

vvouM

joining;

J.-i9

sliowij a part t-lfvalinii «jf a circular iixiuldilig as it a segiiKMital peiiiincnt, wimlow cap, or oUicr structure sluvt-inetal cornice work. H shows the cun'wl iiiouKling, •^'»-

Via.

'•'*

ill

two horizontal pieces

shown hy

A and

th»'

( ',

tniestH-tion of

all

the

moulds

I>.

In this connection

it

may he proper

no miters are cut on the circular ilie

\v< 'i;l.

<»cciir id

arising

licin^

MKTAl.

horizontal pieces,

l)laiiks,

remark

to

that in practice,

the miter-cuts heinj: place*! on

the circular mouldin<: trimmed after

aii
it

has

iieen fonne
In Via.

•i'hi

cuned

mouhlinirs

is

shown

B

.nav

lie.

IS 15,

ohtainin;; the blanks for

no matter what their radius or pnjfile

E

draw the center

Kir>t

method of

the

in elevation,

line

descrilie the outer cur\e A.

A

U, and, with the desired lenter.

.\t ri«:ht

a section of tin- profile as position, ilraw

angles to

shown

liy

A

H, in

(1).

its

pmper Fnun the line A H

various nienil>ei-s in this .section, project line> to the center and. iisin;,' H as center, descrilie the varituis arcs and a.s 1, 2, 3, and t

;

elevation as shown l>y .\ H (' in Fi^. .T)2. only partly <-oniplete the diown in Fijj. •{')'i. In the manner liefore ile>cril»nl, averap* the

prolileC

D

liv

the liner./,

H

through thccent«'r from which to strike the lish

f

on

the line r


stretchout fnun tivelv

from

<

*

to <

to

extciidiiij^'

it

at ri^hl anj,'lcs to

(

and

and fn»m

it

to

intersects the lim-

intersects the

fiimi r to »

it

M. at F.

Then K

Centrally on the stHtion

|)allern.

wlu-rc

until

A

(/

|),

•.MM

line c

('

drawn

the center

D.

e.sial>-

mould, and take the

and phn-e

on the

is


it

a.s shown n>r*jM««'Now, u.sinjj K h.s

SHEET METAL WORK

2t)0

and

e' e",

c' c"

inner arc at

e'

Draw

.

and

e,

and

c'

to E, intersecting the

E

to

(^,

c,

describe the ares d' d",

middle and

then becomes the measuring line obtain the length of the pattern, the length

The

d'.

arc

e'

e"

on the arc 2

being measured

^:

E

E

a line from

center, with radii equal to

in

elevation,

which corresponds to the point e in section. In Fig. 354 is shown the elevation of a

ELEVATION

moulding A curved in plan B, the arc being struck from the given point a. This is apt to ft^hen the moulding or cornice on a building whose corner is round. tain the pattern when the moulding

occur FIT

PLAN

is

is

in Fig. 355. proceed as shown B, the section of the moulding, as in plan,

A

ing the

Fig. 354.

CB

mould

for

a

represents

tached to the mould after

it

is

placed ob-

To

curved

Draw

AC

be-

which the pattern is desired. is atstraight strip which

hammered or

In

rolled to shape.

At pleasure, below the secis not required. practice the elevation From the extreme or outside tion, draw the horizontal line E D. edge of the mould, as h, drop a line intersecting the horizontal

Knowing

line

ED

A

at E.

the radius of the

arc on h in section, place

on the

to

it

E

D, thus obWith taining the point D.

D

line

E

F, intersecting a line

drawn

D

the

center, describe

as

arc

at right angle to

from D.

E

Average a line

through the section, as

G

D

F, H, intersecting the line drawn vertical from the center

D,

at J.

center,

at Fig. 355.

pleasure point

Establish

a,

the stationary

from which drop a

and with

D

line cutting

a' as radius,

ED

at a'.

Using

describe the arc a' a", which

measuring line when laying out the pattern.

292

Now

D is

as

the

take the stretch-

111.1-.

outs liiif

fruiii fntiii

to A

(J

a

u> (i

and

MhlAL UOUK

1

fniiu a toe. aiirl

and fnnu a

to II

with nulii extendiiij; to the varioas (]\ a «'",

ares

the

urr

a'",


inea-sured

to

ami

tl'e

I

•!

respectively. [M)int.s

O.

and

a.

J^iiif?

averagwi «-"*

feiiter,

II. ilesfrilx.'

th»

is

pattern

the

to

eoiTe.sj)ond

tlieiii oti

On

II IP.

tlie

pluc-t*

_'til

arc a' a" in phm. In Fig. .'i.")(» i.s .shown a front

view of an oniainenta! huH'.s-eye

window,

showing the circuhir D, which in this case we desire to hiy out in one

A H (

inouhi

piece, so

or

have the

same

when hammered

that, in

rolleti

the machine,

principles can

to the up|)er

used

connection

in

352 an.

I

mould K

will

it

desire
Tlic

he aj)plicd F, as were witli

—

Figs.

l''«-

.{.-..i.

To ohtain

tlic l)laiik

tor ilie hull '.^-cve winiiow .sht)wn in Fig.

proceed as .shown in Fig. 3o7.

I>et

AR

(' 1)

of the l)uir.s-eye struck from the center F.

and perpendicular

mould, as

II

window

I.

lus

lines

Thnuigh F draw the

lior

3.'>7.

FiK.

H«'ction of the

iiot?

repre.sent the elevatio

ELEVATION

SECTION

/ontal

3^^-

shown.

shown

average the line

li\

II'

I''

I',

80S

In il>
pro|M'r position,

I'hrough the

extending

it

until

Uuf it

draw n of the

intersivLn

SHEET METAL WORK

262

the center line

B

D at J.

Where

the average Hne intersects the

at a, establish this as a stationary point

a to

I

and from a

to

H, and lay them

;

mould

and take the stretchouts from

off

on the

and a

to

line

H^

H* T from a to P

As

respectively.

1

5 in elevation represents the quarter-circle on the point a in section, divide this quarter-

into

circle

equal spaces, as Now, with radii equal to J r, J a, and J H\ and with

shown.

J

in

Fig.

358 as center, de-

scribe the arcs I I.

on one Fig. 358.

ner arcs at a and 1

H

From any side,

H, a

a,

and

point, as

draw a

H,

line to J,

intersecting the middle

and

in-

Take

the stretchout of the quarter-circle from to 5 in elevation in Fig. 357, and place it on the arc a a as shown

from

I.

to 5. Step this off four times, as shown by 5', 5", and 5'". J draw a line through 5'", intersecting the inner and outer arcs and H. Then will a a be the full pattern. 1

From at I

H

H

2fl4

O •iH

U

p.

!3

;>

PLASTERING TIh"

of plastiTiii;; in

siilijrct

into

iK'ie.s.sjirilv »livitl«'»l

in"'

two

relation

of walls on

tlie

iiitrrior

some of

tlu-

various ways of

st-rihe

house

Tin-

st-ftions.

of the lions*-;

to

iii;Mli'ni

first

tiie

Is

seeonil will lirielly ilein

linisliinj^


treats of the plaster-

eenient plaster

tlie

exterior.

INTERIOR PI.ASTERING The

installation of interior plasterin>^

marks the division hetween

the eojnpletion of the roiu/li work on the residence, and of the jiiii.sli that is to follow. hef^imiitii; of the plaeinj;

The

plastering;

cannot he started until

have been lathed, and the lathinj;

can he

ceilinjjs

When

l>e<,Mni.

the very

and

the walls

ceiliiifp

must he furred hefore even the

the huildini;

of the roui^h studdinj;, framework, and

is

ready for

partitions

lathinj;, all

must he

set

in

the |)hnnl)ini;, heating, the piping; and wirin<; necessary ])lace; and he installed and t«'sted hefore the nnist of the «lwellin<;, lifjhtinj;, etc.. in

lathinj; or furrin<;

can he started.

The apparent hreak plaster,

ami

of the various trades, nie«liarv pnwe.ss

materials and

put

diMirs

in

lay

out his mill

fixtures,

niuly

work and

his standing; finish

for

and the

The

[)ainliT

|>luniliers,

tlwcllinj;

and

and

any

nevsiiry

installation.

linish. in

the upper floors, etc., and

work; the electrician^, ic«-

tlitiii

arran<;in<:

t;«'ttinj;

his contract.

Iw ready

place

anxmd

complete

pa|M'rer tlu-n

tin*

commence

healin'^ <-ontract«trs install

is .s(M»n

n-ady for o<cupalion.

a huildin^ are spaced sixt»-<'n inches apart on centi rs. I''a<'h end of the lath n-sts that ea
The studs

Si)

and

f«)r

this inter-

has heen complet«'d, can he secnrin<; their

fi.xtures

and windows,

ilnir >cr%

unahle to resume work until

his window-.sash, set

remainder of their

the proj^ress of hiiildinj; nece.s,sary to lath,

'i'hose

The carpenter can he to

in


(tf

U|Min the leiitiT of a stud;

and the two intermediate

fiLstenin^s at spaces ctpiallv distant

in

ao7

its

length.

slu«ls proviiie

The

«vilin^

art-

PLASTERING four— and in better work, customarily furred to provide lath nailings, of an inch thick with the to lath, seven-eighths furrings nailings

five

—

and one and one-quarter inches or more wide, running crosswise of the This furring is intended to level up the bottom of the floor joists. and distributes the unequal result of their skrinkage or uneven joists,

settlement from the weight above, thus preventing plaster cracks. Before beginning lathing, the carpenter should see that each at its intersection with another wall, is started with a stud partition,

This makes it imposnailed directly against the crossing studding. in behind or over the his laths of the ends sible for the lather to run partitions

—a careless practice that provides a very unstable internal

plaster angle.

The

of an inch thick,

carpenter also sets plaster furrings, three-quarters

around

all

window and door openings and around

the

walls at the height of the top of his base skirting, so as to mark the work of both plasterer and lather end, and to provide points where the finish woodwork. It is essential for the carpenter to for the nailings for cornices, door-caps, etc., before the place any necessary furring is begun; also any other furring blocks that may be required lathing to secure the setting of his fixtures or to support and the

by

plumber

carry his pipes.

LATHING

Wood

Laths.

Wood

laths are put

up

bundles of 100 laths;

in

and are nailed upon the studdings of the wooflen frame, with a space This distance is sufficient to of one-(iuarter inch between them. still and or swelling, allow for lath provide a firm clinch shrinkage

for the plastering.

If the

clinch will be weakened.

down on

is much much more,

space If

less

than

the laths

this,

the plaster

may

the ceilings with the extra weight of plaster.

possibly sag In no instance

should these spaces between laths exceed a width of three-eighths of

an inch.

The

clinch, or key, of the plaster

formed by the mortar being

is

the laths and then spreading out pressed through the spaces between back of the laths upon both sides of the crack, so forming a tie, or clinch, that holds the It occasionally

mortar firmly and securely

becomes necessary

to lath

in place.

on very thin furrings

a heating pipe, a brick or iron support, or .some other such exceptional instance of construction. In that case a wider space

to cover over

298

>>

V.WIJ..

T}

?'o

>•

M

te Id

"J

< o

i

-a

3

P en

a ps 6 ^ o u. o -: o '* z w a lO

M K

PI.ASTl.lMNC ln'twttii

ilii-

a strip "f

.

laili^

-^iM-n^tlini tlu' j)la.st»T t-lincli;

iii.i\

m.iim!. ! metal

may

In- iisnl ovi-r <»r

«ir,

around

iMttrr

siic-h

still,

ohstmo-

ti<)n>.

The

wcmmIcii laths an- iiiatir

<»f pine KPspnicc, aiul are only In- frc«' frnm sliouM Tlioy sap, Imrk, ati
l)fst

[lartially sfusotu-d.

ii.'

plaster

occasionally stained from pitchy knotholes, hark, or sjip. now machine-sawn. The old-fashioned split lath has

All laths are

not heen in the market for

now more than

fiftv vears.

the laths are too dry, the wet niortar

If

warp and

and

twist;

if

saturated, their swelling;

is

likely to

hardi-ns or sets before the laths Ix-come

is

likely to |)ro(luee parallel plaster cracks.

Better results can he ohtained hy i\s\u^ wet laths, and laths
ensure xtter work

two

cause them to

it

wood

laths,

it is

when

hotli

sometimes

mortar

thou},'ht to

are recpiired at each end of the lath, cither upon the eeilinj; alone or upon lioth wall an«l ccilin<^. It is more than doubtful if this re(|uiremcnt produces the desireil ri-sult, as two I

nails in the lath

if

eml arc

nailinj,'s

likely to start a split,

which

may

he incnnise*!

hy the pressure ncccssjiry in ap|)lyinfj the mortar, imtil the entire end of the lath is partially or wholly loosened fn)m its sup|Mirt hefore the |>lasterinj; is all Ujjon

the

the wall.

work more secure, w«'aken

sized inch-and-one-i'i;,'hth lon<;

it

Larjjc lath nails, instead of tnakinj; in the .same The commonway.

"three-peimy fine"

— nails

fasten

the

laths M'curely, ••ven the ceiling nails rarely AI»out five pulling out. lie of nails will (o each one thousmd laths. pounds necessary

The joints of laths are ordinarily hroken every ei>,'ht courses. that not more than eij,'ht adjoining lath ends are naile
This means ii[M)n

one stud or

carri«-«l

furriu;:, the next ei;;ht laths, in lM)th directions, U-inj;

hy, endinj^ u|H>n the next wall stud or ceilin;^ furrinj; to either

or

left, thus alternatin/.,' the hreak an
ri^'ht

than a to

larjjer

hundle,

hreak joints every

in

which case

six laths

it

which

is

simpler and easi«T for them

is

e<|ually j^ikkI construction.

placed twelve inclu-s apart, and the lath Such pnvautlon.s. however, urv joints hroken for every oth«r lath. (

Kcasioiuilly studdinj;

is

2on

PLASTERING not necessary in the ordinary dwelling.

They

increase expense;

and

the closer spacing of the studs, especially, provides more undesirable weight to be carried by the house frame.

Wherever the wood studding of partitions comes up against the brickwork of chimneys or a terra-cotta or brick wall, strips of expanded rnetal or wire-mesh lath should be employed, extending seven or eight inches over

upon

either side of such a joint; and,

if

such a joint occurs

an internal angle, future cracking from a difference in settlement or shrinkage may be prevented by cutting through each plaster coat, in

when

soft,

with a sharp trowel.

Of

Metal Lath.

late years

many varieties of metal

lath

have been

use of such lath is generally required placed upon the market. The in and other on boiler-room ceilings, places exposed to strong artificial heat.

Many

varieties of metal lath

—including

—require supports at closer intervals than

all

those

made

of wire

provided by the studding, nine inches being generally considered the best distance. This necessitates either a closer spacing of studs than is otherv\'ise necessary or is

desirable, or a series of furrings fastened to the wall studding.

There are some metal laths

—that are

—generally those made on the expanded

in one direction, to allow of a spacsufficiently principle of than nine inches but, for ordinary wire cloth, ing supports greater stiff,

;

no wider distance should ever be allowed, unless the cloth is itself All metal lath should be securely fastened by artificially stiffened. staples,

and stretched before

nailing, to increase

its stiffness

as

much

as possible.

In using metal lath, care should be taken to prevent plaster cracks along the line of jointure. The use of metal lath also requires three coats of plaster, in order to stiffen the lath sufficiently to resist the pressure required to finish the last coat. Lathing and plastering are generally estimated, and the various materials are all figured, by the square yard. In small work, no openings are deducted unless they exceed sixty square feet in area.

In

by quantity, when openings are allowed for, it is sometimes customary to add half of the contents when measuring

figuring

up

plaster

closets ; while small triangular wall pieces are figured as in order to make for the extra amount of labor

though square, required in plaster-

up

ing such restricted or odd-sized surfaces.

The

use of expanded metal or wire lath

300

is

frequently

demanded

PLASTKUINO by the

hiiildiiij;

laws of soim-

proof or lirst-elass

of pliislcr hoard are in

extensively advertised.

shwts of 32 hv

lartre o

3(>

*

framinjj.

One

always re<|uintl on a

fire-

i)uililiii^'.

makes

Sevi-ral

cities, aiiid is

eomc

Tliev inehes,

coat of [)laster

in

and are

—

tiie

eitrlit

Ix-iri^

wide lM)ards or

nailetl
work

tliree-coat

in

market and

inch

— may

then

Ix*

dispensed with. These hoards .save time, heinj; r.ipi
— sometimes even after the wall has heen pa|)ered. PLASTER MATHRIALS

principally compo.sed of lime, sand, hair, and uHiter. in dilVerent .sections of the country from calcine
Plaster

is

Lime

obtained

is

carbonic acid and moisture contained

limestone, the

the stone

in

being by the burning process. The wliole theory of plasteris based ing upon the re
something approaching its original state. The slakimj of the lime provides the moisture nece.s.sary for the process of crystallization that while the .sole purpose of applying it prcMluces the sei of the mortar; is to present that much more surface uj)on the wall in .several coats of which it was originally deprivetl in to ab.sorb the carbonic acid

—

burning— from the

air.

The

thinner

tin-

coats and

tlu'

constituent.

work

coat plaster

until

it

is

—

to be considered as better than two.

Properly burnt lime slakes

addnl,

larger their

absorption of this strengthening For this reason- and solely for this reason is three-

total ex|K).se
I'asily

and completely, w hen water

convt-rted into a line dust, which, in

its

is

turn, is

moistened and turned into a paste iniijer action of (he waltr, which This is bubbles and hi.sses with the heat generate
what

is

called the slakiiuj of lime.

for plastering

increases

to

\'ery rich

Can-

and

is

should also Iw taken

W(mh| and not with

t(»

the U-st

its

then almost pure white in nnist be delivere«l as us fresh |M>ssible, and •slaked,

and pure lime

original bulk by U-ing color. Lime should always U'

about twice

u.scertain that

coal.

.101

in tightly seal«>»l barn-Is. it

ha.s

Urn

burneil with

PLASTERING

6

Sand

is

broken or rotten rock which has become decomposed

spontaneously or by the action of running water. That made by running water, or from stones worn small by rolling over and over

upon the beach, and so lacking

is

in

of particles so nearly round in contour angularities of surface that they are not good

composed

material for mixing in any mortar where strength is a recjuisite or The particles of rotten rock decomposed by exposure necessity.

make good sand for mixing with mortar, their more with many sharp and angular corners. being irregular, shape Sand obtained from ledge stones contains the essential elements of

are better adapted to

those stones, quartz, feldspar, and mica being present in granite formations, and lava, obsidian, etc., in volcanic sand. The sand

coming from the

softer stones is generally more thoroughly disintegrated, being frequently so rotten as to be entirely unsuitable for use in plastering. In most parts of the country the principal supply of sand

now comes from

the beds of ancient lakes or rivers, and

True sand, no matter how

sand.

fine,

may

is

called pit

always be distinguished

from dust by dropping it into a glass of water, as it will invariably sink to the bottom without leaving any appreciable dirt upon the surface.

For plastering purposes, sharply angular sand

Good

essential.

and

is

river sand, the coarser the better,

so clean and free from dirt, clay,

generally employed

The market

is

and earth

is

is

not absolutely

obtained so easily,

stains, that

it is

most

for plaster.

third necessary constituent is hair. The best hair upon the cattle hair obtained from the tanneries. The hair should be

of

good length; and, if too lumpy or clotted, it should be separated by soaking in water the day before mixing it with the mortar, as this

method of separating the hair

is

less

dusty and more healthful than

beating or whipping it dry to obtain the same result. Occasionally brick dust is added to the mortar for coloring, when it is likely that the mortar will set more rapidly especially if the dust

—

is

mixed

in shortly before using

and

is

dry

at the time of mixing.

All

brick dust should be sifted through a fine sieve. Besides brick dust, a such as lampblack, ivory variety of colorings for mortar are used

—

black,

powdered charcoal, Spanish brown, raw umber, burnt umber,

red aniline, Venetian red, Indian red, vermilion, ultramarine blue, blue, chrome yellow, and, occasionally, pulverized clay. Mineral colors should be preferred to earth colorings. The latter

indigo

302

PLASTKItING the

weahi'ii

plaster,

they ean

uliiii

terials j)ossible for It

is

ami

faile

obtained-

Ik-

tiiitiii<;

the

Xariously colored

rupiilly.

make

iiiial

the

saiui.s

most diirahle ma-

In-st aiul

plaster coat.

to state arbitrary, set, hard-and-fast y)rf)portioii.s im|)ossil)h-

for the iiiixin;^ of plasterinj^ for either exterior or interior

lime and <;rades

dilVerent maki-s of

The

work.

sand, alone, vary sufficiently to make any such statements exceedingly inadvisable; while tlu* purand conditions under which the plaster is to be usctl, fre<|uently (»f

jH)sc

occasion considerable chanj^es in "Working" the IJme. The is

This

the ulakiiifj of the lime.

its

prop<jrti(jns.

process in the making;

first

consists, as aln-ady

.sai«l,

tif

plaster

in

simply

hanl, brittle hnnps of its orij^inal form to a sm(M)th [)aste by mixiiii; it with water. It is of the utmost imj)ortance that the limi- should be entirely and completely slaked, antl the jKiste smoothly ritlucin^

tlie

and evenly 'I'he

irorkcd, before ad
lime

wide and 7

is

feet lonj;,

and

convenient location with 1k)X

at o!ie

placed

any of the other in;,'redients. box «)f boards about

in a iitortur-hcd, a

slaked

a foot to ei<;hteen inches hi^h,

its

bottom about

level with the top of a

end, and about two feet lower

in

4 feet

in .some

.set

second

Both

^rade.

mortar and lime-slakini; beds should have tif,'ht bottoms and stronj; sides, well braced to resist the j)ressure that will come U|)on tluin

when thev

are

.\

full.

(Iravel in the mortar delays

and work.

and

in<^

lat«'r

.scrt-ened

shouM

cau.ses extra tn)ul)le

workmen

whiU- plastcrintj

^'ood plaster material will Iw lost in hnrrii'dly

and nnich

floatinj^,

throw

(luantitv of .sand alreadv

Toorly scn-ened sand

also be near at hand.

or pickinj; out these <^ravel stones in the rush of aj)plyin^ the

mortar on the wall.

The barrel lime is em|>tied into the upper l»ox, ami water is workman breaks up the lumps and works the mass |)oured on while a Tin- thorouj;!! workbiick and forth in various directions with a hoe. inj;

of the material at this stap"

ing.

The

tendencN of

tln>

is

m-cessary to jMisure

can-less

workman

is

to

its

compl«-t«' slak-

hoe back and forth

centtT of the beil without any repird as to whether he is stirring up till- mortar that isdrtwn on tin* bottom bojinls.or whether th«M"orners are drawn into the mixture and worked as «-venly as llu* remainder of in the

the Intx.

If

the past«-

is

of lime, or

if

not thon»U|,'hly the water

and

«'venly worketl to

an

i'^\\u\\

not con«lucl«tl to every particle the other in^'redienls are mixed in l>cfon- the paste 'm

consislcn«'V throughout,

if

is

303

PLASTERING the lime will be apt to blister and slake out unevenly, evenly prepared, If the corners, for instance, after it is upon the wall. trouble causing are imperfectly mked, lumps of clear lime will afterward appear. under the hoe of the workMany of these lumps will pass unnoticed the mortar, and will not be found until they are flatman

tempering

tened out under the wall trowel of the plasterer. If too much water is used in slaking the lime

amount

added

is

great that slake too tardily.

at

once—the

If too little

pile is chilled

water

—especially

and forms

added, the lime

is

if

into

a too

lumps

is left

so

call it) that many small particles entirely dry (burns, as the plasterers When too much fail to slake through lack of sufficient moisture.

chilled that a considerable portion of ess of slaking

is,

becomes so thoroughly strength is lost; and the proc-

in the first place,

water drowns the lime

its

it

by the very excess of water, much retarded.

The

the slowed up very cold water is added, although process is also At the lime. of the reaction from the water soon becomes heated if

enough water should be put on to initiate the slaking process. After this, as the slaking proceeds, more water should be added as

start, just

all times. needed, taking care to keep the lime thoroughly moist at water with be covered lime should and A very active quick slaking from the very beginning, to guard against the possibility of burning.

If the lime

once burns,

it

will

afterward be impossible, by any amount lumps that are then caused. Rich

of working, to get out all the fine

and bears

lime will afterwards work cool, troweling when being

is little likely to crack, finished, without the surface peeling off, blister-

ing, or staining. If

lime

is

the screen when the lumps of unslaked lime escape through it becomes very difficult off, and get mixed into the mortar,

run

not possible for the plasterer to the mortar when working it on the wall; and get these lumps out of the results of their afterwards slaking out will continue to appear long If they occur in the first coat, at various after the house is finished. to eradicate

them afterward.

times after the the entire

first

It is

— completed frequently extending throughout — or expand, suddenly year these lime lumps work

is

will

bloiv

outside them and making a large forcing out the surface plastering an inch in diameter, which, if upon about blister or lump, generally If this unslaked lime gets into the ceiling, almost invariably falls off. the final coat, much the same result occurs, although the particles

304

i'i.A.^ii':Ki::G

«il liti. >-Mii -iiiall»T in size. In.st(*a«l of U-in^ larj;«-, tlu* resulting holes an- then eoniparativcly small, running; generally alnjut the size of the head of a j)in, and the entire surface of the plastering is frei|Uently j)itte
art-

the sliapf of a white dust. In the hruwn nuigh-coat, the s|M)ts of white, unslaknl linu- are How(|uite easy to see, as they are often the size of a Uaii or jx-a. ever, in the final white coat, the.se

.sjxjts,

In-ing smaller

and of the same

color as the rest of the mortar, do not show.

After it has once iHgim to warm up, the lime should U- worke
cream.

After slaking, the lime should he run olf through a fine sieve ho.x, into the ne.xt lower

{No. 5 screen) put at the end of the slaking compartment, or niortar-hed. The screen is

inten
keep out any

lime lumps too large to slake before the mortar is u.sed, or anv flintv settlement that may he found in the lime, and to allow only a pure and thoroughly mixed hydrate to he admitti'd to the hed.

When drawing

or ruiming off the lime, a large supplv of .sand hand to scatter in the bottom of the

alreaily .screened shoidil he at

mortar-bed and to gradually to

u.se

This

fills.

for .stopping leaks that .screened

may appear

sand .should be

sufficient

{is

the Im)X

in

atnount

complete the mortar mixture. .Vii ani|)le su|)|)ly of water, either or in ho.si- piju-d from a hy
in barrels

hand

—

anv

to avoid

For the pudi/ befon- running

(tr

oil',

through which

it

i)ossibilitv of the

be

made even

thiimer

The sieve consistency of milk. stniined should also be finer, of alntut the mesh

and may be of

is

lime burning.

finish coat, the paste shoulil tin-

The paste for this coat is often of an ordinary flour or meal sen-en. obtaineil by rumiing off the lime a second lime, as by this means a c(Mt|er

working putty

The

is

seeun-d.

of lime that mortar for |ilaslering bi'fore bi'ing u.sed, is a mueh-«li.seu.s.sed ipiestion.

stated

mixed

in

leiigtli

shouM It

is

!»<•

mi\e«l

generally

architectund specifications, that "the mortar shouM U* two weeks before using." .\s a matter of fact, this

ten ilays or

re<|Mirement is not always either wis«old English work, lime mortar wils

(»r

left

desind>l«'.

It

is

true that, in

covered ovi-r with earth in

stand for long peritnls of time, often six months to three years elapsing

no»

PLASTERING

10

before to

it

was used. In this country, such slow-going methods are not While lime does gain in strength by standing in this

be expected.

thin putty state before sand or other materials have been

mixed with

it,

yet three or four weeks, at the least, are necessary before the increase becomes very apparent. It is also necessary that the paste should

remain moist, by being kept covered all the time. At the end of the fourth month its strength will have increased about one-fifth, and this gain has been made during that month. From then on the gain continues, but gradually decreases in amount. It is more economical for the plasterer to use a lime that has been

most of

when tempered down, it will work freely much larger proportion of sand than is taken

slaked for some weeks, as,

with the admixture of a

up by lime mixed as soon as it can be readily worked. This extra amount of sand does not add to the strength of the mortar; but, as it causes the lime to cover a greater surface, it is a considerable economy for the contractor,

made, however,

at the expense of the quality of his

work.

Lime mortar need be

left standing only long enough for all its be thoroughly slaked, and, if properly mixed and wet down in the first case, a great deal of time need not be required to

particles to

effect that result.

This once secured, the quicker the mortar

is

mixed

and put upon the building, the better and stronger will be the plastering that

is

obtained.

which

it

It is further

claimed that the accompanying loss of

—from the properties — has already absorbed from the lime much better suited

limewater

is

also very harmful, as this water

is

on the process of mixing than newly added clean water. the lime has been long standing, it may be necessary to add clean

for carrying

Yet,

if

water to replace the water lost by evaporation or seepage, although mortar mixed with clean water never becomes so hard as that mixed with the water obtained in slaking the lime. The sand and hair are next added, the hair being put in before the mortar becomes too stiff to work readily. After the sand is mixed, the mortar should not be left to stand for any length of time, as it

would become considerably set and a loss of strength would result. If the mortar does become set in the bed, reworking woitld be necessary it could be put upon the walls. The strength then lost bears a direct relation to the length of time it has stood, and the solidity it has attained, before this final working up.

before

306

\

PLASTEIUNG

11

In plastt'riii^ mortar wlun- hair is rc«|uirf
The

worthless.

when

to tlie action of the wet lime as to Ix- almost or (juite

the mortar

hair

v-aiiiiot

well

run

is first

olT,

after a liine-an«l-.siin(l nii.xtun'

were

attemptinl to

it

ljrlii<^

Im- mi.\e
while

had

is

it

evenly, except at the time in a very thin paste. If.

lu'en stanilin<; for .some

months,

it

to a sudieiently lluid state to receive the

hair properly, hy wettinj; it down a .<econd time a consideraMe pn)[K)rtion- varvini^ from a (|uartrr u|) (o ..'most a halt- of its .strength would Ik-

sacrificed.

Bearinir these facts in

mind

— once certain that the lime

is

slaknl

-

would appear better that not more than a week .should elapse U-fore the u.se of this mortar; and a less time than that is, under many circumIt is evitlent that no more lime-andstances, unilouhtedly desirahlc it

sand mortar should

Ik*

mixed

at

one

timi-

than can he

u.sed

within a

few days at the most. The lenf,'th of time that mortar .should Ik* allowed to stand, is deteniiined more or less Ity the dryness or moisture of the atmo.sphere. The
as the

out, or eva{)oration, of the iratrr of rrystallizotioti, as it is called. It has already been .said that limes made in dill'erent parts of the

country vary extensively in their chemical composition and pntjMTties. A knowledge of the chemical comj)osition of lime mortars and the individual pecnliariti<'s

the lime l(»cally used,

t)f

utilize the principles

is

neces.sary In-fore

here

.set forth. In ap]»lving tiic eastern part of the I iiited ."^^tates, the limes friniuently contain from a third to a half of carbonate of magnesia; and the mortar in which

cir

attempting to

sut-h limes an- employe
To

SIMM

u|),

lutely n«Te.s.san*;

while

tin-

and thoroughly bed through a line there no longi-r than is ab.s«>-

the lime should be slaked as evenly

It should Ix' as jHKSsible. sieve into the Jnortar-lied

and

if

it

original mixture

nm It

nil"

froiu the slaking

should

lie

could be possible to add the hair and siunl is

suflieiently moist to take

up and

W(»rk

tlif ••ntire amount of the latter material to be ailded. the residting mixture would undoublrdlv !><• that niueh the stronger and mor»>

durable. .Mixing the Mortar.

the lime pa.stc

is

The amount

of sjind to

Im- nnx«'«l

in

a variable (piantity, »lepeiiding ti|Mtn the sand

307

with it.self,

PLASTERING

12

upon the quality and thickness of the lime paste, and also upon the nature of the work for which the mortar is intended. With excepamount of about two times the bulk tionally rich limes, sand to the of the lime measuring the slaked lime in the form of a rather firm

— — paste may be added.

As will be seen, this is a most uncertain propora great deal depends upon the firmness of the lime paste alone. Allowing for variation in size of the lumps of lime and their closer or

tion, for

looser packing together, it may perhaps be better to say that the sand should bear a relation to the lime, before it is slaked, of from three to

four and one-half times

its

bulk.

finer the particles of sand, the more of the latter should be employed, although the finer sand does not make as hard or as good mortar as the coarser variety. If both are

The

richer the lime

and the

clean and sharp, the finer and coarser varieties of sand may be mixed together with good results. Most laborers are apt to stop adding sand,

merely because the mortar mixture becomes hard to work when the mixpaste becomes too thick. This is poor policy, inasmuch as the

becomes much harder

ture

to

pleted, a day or two later. The fineness of the sand

work when is

the tempering

an important

factor.

A

is

partly

com-

rather coarse

as well as sharp sand is considered best, as the amount and capacity of the voids left in such a mixture would be of such size as, without any

doubt, would provide space to contain lime sufficient to cement this granular mass very firmly together. The close pressure and contact of the sand particles would also lessen the possibility of settlement or shrinkage, with accompanying map-cracks. The hair may be mixed

adding of the sand or when but a very small proof the latter has been worked into the lime mixture. The hair portion the mortar by means of an iron rake. It should is mixed with generally in either before the

be thoroughly mixed, and enough should be used to make it impossible any small sections of the mortar in which the hair cannot be

to find

seen. to

This

will require

from one and one-half

to

two bushels

of hair

a cask of lime. If the

surfaces,

it

mortar

is

to

will carry

be used as a

first

coat on stone, brick, or similar

more sand, and hair

is

not considered so essential,

a half-bushel to the barrel of lime being generally ample. If too little sand is used, the plaster is liable to dry too quickly when setting, and, after it is dry, will crumble very easily, showing up too white, or ashy

308

PLASTKKING j^ray, in is

Mortar

Unt

If

appcanincv.

liabk' to fall off,

and

For the

putty

run

is

sand

little

For

of sanil. off.

when

on

for a secoiul coat

hut very

amount

.saml has \)cvu usf«l, the pla.sk*ring

will cniinhli-

consistency of niixtun". finitli)

mudi

is

lath

nil)lxtl iK-twci-n the fingers.

may

final coat

The

used.

this coat, the .sand

For hard

13

finish,

Ik?

of uixjut

(the putty

hanler the is

mixed

when marhle

tliLs

c<jut

same

or hard

finish, the less the

at the

time when the

«lust, hrick ilust, or

it is genenilly mi.\e
anything of that sort

added,

is

mortar-l)oard Paris,

is

mixing,

its rapid .setting, whidi occurs in a few moments after ^^^len once set before being aj)j)lied, it Ix-comes useless.

No more

water than

account. of

is

nccessiiry .should be added, either in the mix-

or in its sub.secjuent tempering, as over-much of a considerable projMjrtion of its of the lime wetting dej)rives it and the also retaRls strength, setting process by giving that much more ing of the mortar at

moisture that

is

first

necessar}' to be disposeil of

by evaporation or

crystalli-

zation.

A bushel of lime is standardizeil to weigh SO pounds; 2(H) |>ounds allowed to the barrel; a l)ushel contains about one and one-<juarter cubic f
.'}

sand, and a bushel of .sand weighs about 120 pounds, and wet mortar 130 or 132 pf)unds. When hard, mortar is figured to weigh alniut 110 pfHinds to the cubic foot.

To summarize

—one

barrel of lime, 200 |M>unds, will take alK)ut

In most localities a load of .s;ind is supixi.sitl to a cubic yard of .sand. contain twenty-seven cubic feet, or a cultie yard; but it is friHjuently less

than

this,

extending

barrel of lime should

al.so

down be

to two-thirds of the

u.sed

amount.

about two barrels of wat»Tand

To

the

— as we

have seen

— upwards of two bushels of hair for a

in pa|M'r

bags wi-ighing generally something inuler eight pomids and

containing enough hair to

In-at

uj)

into a

IIair
first c«)at.

nieasun-d

bu.slu-l.

This

when the lime has Ik-imi slaknl and the whole or 10 yanis (aUiul barn-Is) of mixjHJ together, will amount to mortar; and tin- amoimt shoid
amount

of material,

.!.')

.'•

latlud an a. reipiiring about (KK) laths to surfaiH". The final skim coat is mixe«l mughly to the following pn»|H»rlion.s: a^k "f lime to a half-tub of wafer, which should fake up aUnit a A <

300

E

PLASTERING

14

barrel of the hard, clean sand used in the surface coat.

Generally

the plasterer uses a larger barrel or hogshead for water, than the cask in which the lime is delivered. Also, in some localities, the lime will

run somewhat more than 200 pounds to the barrel, Maine lime from to average 220 pounds. Rockland lime is

Rockland being supposed

considered in the East good lime for scratch and brown coats, but many masons prefer Jacob's lime for the finish coat. It should be remembered that the bulk of the completed mortar mixture does not equal the total combined bulk of its various ingredients, but is less than the aggregate bulk by about one-quarter.

PLASTERING Interior plastering ings. first

is

now

applied either in two or in three coatlath, the

Three coats are always necessary on metal or wire

coat being required to stiffen the body of the material sufficiently thorough working of the remaining coats. Even upon wood

to allow

laths, three coats

make a

better job of plastering than two.

and body are obtained by the addition of the extra

strength

Extra

coat, pro-

vided time be allowed to dry out each of the coats thoroughly before the next coating is added. It has now, nevertheless, become the general

custom

to

employ but two coats on the

less

expensive grades of

resi-

dence work.

The

plaster mortar

is

applied to the walls with a hand trowel of

about four and one-half inches wide by twelve inches long, having a wooden handle that is parallel with the back of the blade. After the

steel,

mortar

is

put on and roughly smoothed out with the steel trowel, wooden trowel, about four inches wide and three feet

the darby, a long in length, is

taken by the

workman and used

to level the plaster surface

and work

it

to

form density. The flat part of the darby half-inch or slightly more in thickness.

—

—

with a scouring motion an even thickness and uniis

generally of hard pine, a

Three-Coat Work. The best interior plaster work always used be put on in three coats, and was worked to a final thickness of about seven-eighths of an inch. Of the three coatings, the first is the

to

when dry, it may be strong enough to resist the A large part of the pressure of working the coat or coats to follow. advantage of three-coat plastering is obtained by thoroughly drying each coat out before applying another, thus securing the added densthickest, so that,

310

I'l.VSTKUlNG ami

ii\

tirinly

iiiadf jwissihlc \t\

.strt'ii^tli

and

tlit*

futvin^

suhsitjut'nt

c-oatinj^

surfafe u|H)n wliicli it is Ijcin^ placetl. n)ii^h mortar U-fon* it finally dries and

strtnijjly a<;aiii.st tlu*

or trowflin^' up tlir niakfs it much mori' compact than at the time when it is first aj)pli«-«|.

|{iil»l)iii;,'

M-ts, also it

15

is

jH>.ssil»l«'

fn>m working

The first coat,calle
of the wixnlen laths, throu;^h the crevices plaster hehind the edijes which has In-en forced. Mefore this coat thon)U^hlv dries, it Itetwirn the surface

is

scratched (hence

The

purj)ose.

name) with

its

surface of the secoiul coat also

a tool di-signed for that is

sometimes scTatchetl

a wo<Mlen float or darhy like that used to ruh over the surface, before adding the finish coat. When one coat is entirely witli nails set into

dried out before another

ap|)lied. this scratchintj

is

the scratches forming: a clinch or to unite the

more

tie

—or

of this second coat-

up

brown

and even, especially

coat, as

at

all

Hefore the finishing coat

walls.

always necessjiry,

firmly to the prece(lin<;.

The .second coat generally contains and much less hair than is nece.ssary in true

is

permittiu',' the sul)se<|uent coat

is

it

a larger pro[)ortion of sand first coai. The surface

the is

calKnl

— njust he

l)n)U(:ht

angles, and he |)lumh ujmhi the applied, lumj)S must he removinl

other imju-rfi'ctions corrected, and the mortar must iR-come Ix- nihlud sufficiently set to allow the entire surface to up with a float

and

all

or darhv and so

To

mad compact and *

.save time, the plasterer

sjrond coat on over the

first

firm.

adopted the custom of putting his still green. 1 he

while the hitter was

(practically one thick coat) was then darhied and same as in twu-<
comltinetl

mass

treated the

sults as are secured in

the

first

anil time. neiit

by thus working two coats

a job of plast«'ring,

(juireini-nts

ti»g«'ther

are obtaineil

«)r While this method do<'s not furni.sh .so giMxl or .so |MTmait

is

m»Mlernly c«>nsi«leml as meeting the

of three-<-oat work,

The saving by the plasterer,

in this sort in

«»f

when .so s[M'eifi«'«l. thnnwoal plastering

the ex|H'nse of doing his work.

.n

1

rt^-

is made chiellv The owner |>ays

PLASTERING

16

more money than a two-coat job would cost him, and actually receives of work. The second coat, too, dries substantially the same grade more slowly when applied before the first coat is dry and hard, and there

is

first

work

is

much

saving in time as is generally believed. attempted at all, it should be insisted that the

therefore not so

If three-coat

coat be thoroughly dry before the second is added. The final coat is generally composed of lime putty, with a small

This of white, clean sand, gauged with plaster of Paris. proportion If a color is considered desirable, surface. finished whitest the gives a colored sand

may

All lath cracks or settlement cracks

be used.

should be cut out and patched before final coat is about one-eighth of an inch

occurring in the previous coats the last coat

is

The

applied.

an even and from chip cracks or the white finish mortar should be

and the surface is burnished with the worked sufficiently to straight surface, and thick,

other surface defects.

The

run through a sieve of not

lime for

less

steel trowel to

free

it

than ten meshes to the inch.

thus combining the first two coats when green, the next step of methods of work, was to apply but naturally, in the development of increased thickness, and scratching it ready to one coat, making it

From

receive the finish finish the plaster

process

is

skim or white coat, except when it was desirable to with a rough surface, or to sand-scour it, as the last

sometimes

Rough

called.

Plaster Finish.

If the

mortar

is

to

be finished with a sand

or rough finish, two coats are applied. The second coat which should be put on only after the first is thoroughly dry is substantially the same as the brown coat described

—

—

tlie rough finish being secured by working the surface of the second coat, before it dries, with a soft-faced float and a mixture of sand with some lime added. Sometimes the surface of the float is of carpet

above,

sometimes of cork or other soft wood. Only so large a surface may be readily covered at one time, can be floated, darbied, etc., In this case no hair whatsoever is put in the before it has time to set.

or

felt,

as

second coat, as the hair destroys the evenness of the surface that is obtained by the scouring action of the particles of sand rolling around between the surface of the float and the face of the plaster. K long used for scouring, and the surface is worked to an even and true face, care being taken not to leave any marks from the

float is generally

instrument

itself.

312

PLASTERING

17

While it is m*iR'rally tlii' custoin to ay rou<;h-\v(»rkin<; the surface n{ a very the first coat.

If oiie-
the consistency of the coat surface-finishe
employe*!, hair must

Ik- use
must remain nuieh the same, whether

In that case, however,

it

is

and it

is

not jxjssihle to

work the surface as true and as even as the surface of a second coat. Two-Coat Work. Most j)!aster work now consists of only two coats.

The brown mortar employed

for the first coat should he

made

of

enou^'h to he wijrked, with stronj;. The first coat of well-<listril)Ute
fresh lime used as

soon as

it is stiti"


mortar must always be put throuj,'li

plaster face of this coat

must be made as true and even as possible on surfaces

and angles, and plumb on the walls. After the first coat is sufficiently float consisting of a piece of lianl set, it may be worked again with a about the size of the trowel. Sometimes the faci- of this float is pine covered with

ment on the

felt

or other material to produce a rough textural treatThe first coat should run a stnjiig fivesurface.

plaster

should be thonnighly dried out. eighths inch in thickness, and It is generally inadvisable to attempt to trowel a two-coat job If the attempt is made to float the first coat when it is verv smoothlv. too thin or insufficiently

.set,

the instrument

is

likely to leave

likely to crack.

marks

It is In-tter to

on the wall, and err on the side of caution, as, if the jilaster has become .slightly t(H) dr^-. it may easily be dampened by sprinkling water upon it with the plasthe plastering

is itself

broad calcimine brush and following it inune«liat«'ly with the The use of water in this way has accompanying a«lvautages

terer's float.

tends to harden the j)lastering and to prev»>nt the hairs when otln-rwise tlu-y would have gathering along the edge of the float, to l)o shaken off every few moments to jirevint their rolling under the in

that

it

instnmient and Iwing pressed into the surface of the plaster and rolls, in such a waiy as to .show through «ven the finish e»)at. (

are shoiiM

l)e

taken to see that each coat invariably

is

in tuft.s

al).solutely

drvaiwl hanl Infore the addition of anotlur coat is atteni|»(«tl. ( )therwise the later e<»at will fall olT, in great
Tl.T

PLASTERING.

18

first coat is only partially dry when the second be seriously injured by the pressure brought upon

happen that the

when

will

it

applied,

Its clinch to the lath is

floating.

is it

thus often partially or wholly

broken, sometimes the plaster falling entirely

off,

leaving the laths

the

same as the

exposed.

The

finish

skim coat

second coat in two-coat work

in three-coat

The

The Finish Coat.

is

finish, skim, or white coat

should never be

and

applied until the earlier coat or coats are it

liable to

is

crack

if

danger of injuring the before

is

it

entirely

hard, thoroughly dry —quite from the

put on before first-coat

dry and

more sand than when

final

work.

set.

aside

work by the pressure

A

as

possible of troweling

simple putty coat should carry

hardened by the addition of plaster. If plaster is used, the mortar should always be gauged (that is, plaster should be mixed with the putty) after it is placed on the mortar-board. the finish

is

The

usual process of gauging consists in making a hollow with the trowel in the midst of the pile of lime putty lying upon the mortaris filled with water, and the plaster sprinkled the whole then being mixed rapidly with the trowel and put the wall immediately, before the plaster has time to set. The

board.

upon upon

This hollow

it,

proportion of lime and plaster, while variable, averages probably onefourth to one-fifth plaster.

The

finish is skimmed in a very thin coating that is generally than one-eighth of an inch in thickness. It is immediately troweled several times, dampened with a wet brush, and thoroughly less

troweled to smooth

up the surface and prevent

it

from chipping or

The water

cracking. prevents the steel trowel staining the surface, but the plaster should not be too wet, as it will then blister or peel.

The whole

surface of the finish coat, whether of putty or hard finish, should finally be brushed over once or twice with a wet brush while, if a polished (or buffed) surface is required, it may be gained by brushing without dipping the brush into the water until a glossy surface is ;

—

—

obtained.

Especial care should be taken, in the final coat, to finish all smoothly and evenly so that the point of jointure will not be

joints

apparent. The ceilings are completed first; then the upper part of the wall; and lastly the bottom portions which can be reached from the floor

and thus more

carefully finished

314

up

to the joint.

o 00

« a;

a a

o •a

o o

o

>

o g

II K

•s

<

^

53 (-1

^' S,-' cfl

O ii

3 O

u

m

•a (V

o -•* •

e ^ o d u.

r

< BC

< tu

!! ;:

o '^

7

<

>

a. to

u

U

s«:

rt

i

7

i'LAsri;ui\(;

I'lii-

plastcnr

sulliiinit

M-atFolds

rally

;j»iit

Thr

lii'ij,'lit

is

phistiT

If too

fl(M)r.

are

likely to

is

joint

to

lie

tt-iliiij^

same

a

overliftui

of the walls fntin the siiine

work

i-ompK'trd fn)m tincoats at this jM)int, the

is

elapses —wljich of course, not serious unless the walls is,

Miitn-ated.

lift

lM»ani> al

«'ach of tlu- coats i-wnlv.

in jo'uiiij; the

tiiiu-

show

|)art tin-

witli

<

two men

)ccasionally

one on the scalVoldin^ ami one on (he Hour,

tot^ether, at the

much

rrrnaiinlcr of

r<MHii

n-atli (In-

work

hi;rh to

applinl on thf up|)«T

ami the

sciitroldin^',

tlu'

to riiahle liiin rasily U*

without raising his arms too

19

workin;^

alonj:

liiiish thv

walls

time.

wooden ani^le-heads are used, the plaster cut out from each side, forming a small V-sunk an^le neatly that prevents the thin ed<;e ruiminj; up against the comer-lH'ail fn)m breaking o\L As a matter of fact, the use of a metal (H)rn<'r-bead If

oKl-fashiuneil

tlie

should

Ik*

makes

a far truer, sharper, and straighter angle, ti-ar or hreak the papering when it

and one

afterward

Angles

is

neces.sary;

applied on a stone or hrick wall, a .scratch coat is .seldom l)ro\\;n mortir is very often u.sed without

and the coat of

and of nhout the

.s<'nitch

more

put upon the wall.

plaster are generally linishcd with a wcmmIcii paddle. hair is ii.sed principally to insure a clinch hack (tf the lath,

th«'

plaster

hair

that does not

in the

As if

is

coat

.sand

For a

is

and

u.sed

c-ompositioii of hrick ina.son's mortar.

under these conditions,

h-ss hair

it

is

If a

i;enerallv mixinl with

than when put ujmmi laths.

mouldings are to Im- used, or when for an mujsually stniight, level, and pluinl) surface of plaster is rn|uired, three-n-oal work, put on in the old-fashione
any

finish wh«'re plaster

pur|)o,s«'

sulliciently

and true

level

run plaster mouldings evenlv, and to almost certain to occur in all twiH-coat

to

nvfiid the ine<|iialities that are

plastering.

The

ami

.s<'cond

and

third coats allow opportunities to ohtain a stniight

level plaster surface.

.surface, the plaster then

Individual s|Mits

and amongst them, hringing straight

edge.

(

)cc;isionally

tmeven that .some

filling in

and half

hrought up

it

is

liap|M'ns

jtiitty

may

that

the nuigh

ahsolulely necessary to

U*

to

w(trk«>«l

an even U'tween

to the .saim- faci- l»y m«'ans of the

all

it

sudieienlly even to receive the last half plaster

ar»'

Iwing added and carefnilv

c
u.seil in

ain

i-oaf

make

is

so

the wall

In that ease, a miMiin- of

leveling

up

the rt>ugh work.

PLASTERING

20 If

no finish coat

as the mortar

is

be put on, the surface should be troweled smoothly applied, care being taken to lea-^'e no marks, hollows,

is

to

or uneven places; but if the wall be left with a floated surface.

is

be finished or frescoed,

to

Patent plasters, such as adamant,

Patent Plasters.

it

etc.,

should

are not

often employed for private dwellings, being chiefly suitable for merThe patent plaster has certain advantages that are cantile purposes.

—

such as quick drying and hardening. Its surface self-evident hardens more quickly and resists abrasure longer than the ordinary lime plastering However, a break once occurring, the extreme stiff-

makes

ness of the mixture

more

serious nature than

if

it

liable to extend further

the softer,

more

flexible

ering had been injured in the same manner. The extra stiffness of most patent plasters that generally forms

an important part of

is

and

to

be of a

lime plaster cov-

caused by the cement

their composition.

These

plasters are sold ready for use, requiring merely the addition of a sufficient

amount

of water.

They

are therefore especially adapted

by the inexperienced, and are valuable for executing small pieces of work, as they do not present the liabilities to failure, or loss of time and delay, occasioned by mixing up batches of lime mortar. Back Plastering. Occasionally a wood -framed house is backfor use

warmth.

This process consists in nailing a strip of inch seven-eighths furring against the inside of the boarding on each side of the studs. The space between the studding is then lathed

flastered for

(of necessity a slow and bothersome job) and plastered one rough coat of hair mortar, which should be allowed to dry before any lathing it on the inside face of the studding. As a matter of the of back is much injured by the fact practice, efficiency plaster that the studding, after the seasoning plaster is set, is likely to shrink away from the plaster, leaving a narrow perpendicular crack

is

placed over

m

on each side of the stud, which permits of the passage of cold air. Plaster Cracks. Cracks in plaster occur from several causes. If the distance

between the ends of the

laths, where they join on the too great, the larger amount of plaster in that place, when drying out, may cause a short crack. Any such spaces should, however, be. filled by the lather before plastering is begun.

studding or furring,

is

Sometimes, too, especially in the first coats, cracks are caused by the shrinkage or expansion of the wooden laths after the mortar has

316

I'l.ASrKRlN'G I'lu- rr.siilt is a sfrics of narrow cracks wholly or partially st-t. paralU'l l^ath crackn art- or
in an
and

in the iinishnl

he workcti out when

ing

pla.sti-rin;,'.

the coat before

ii|>

he cut out

slionld

Tlii-y

it

may,

finally sets.

to a widtli of

an

tiK),

If

iu'-h

.s«»

do not «)ftfnup|H'ar float-

wide or deep, however, they or so, and fille
mortar hefore adding the last coat. Cracks of a like appearance are sometimes cause*! hy the rough mortar heing too rich, or l»y draughts of air fn)m o|)en d(M)rs or winof the plastering too <|uickly. The too with of stoves or oft«'n salamanders, drying plaster prcHJuces a

dows drying out portions raj)i(l

An

fn)m similar causes.

experienced plasterer should Im? uhle to determine the rcsponsiblecau.se and take measures acconlinglv, using more siind if the mortar is too ridi, .screening openings to prevent like result

draughts, and using

less fire in his

In green work,

drying stoves.

damage already done may he rej)aireil hy refloating again before the work becomes too dry, softening the mortar with water if necessim*. Tracks sometimes wcur in the angles at the ceiling or corners of

When in this location, they may be cau.se
In that

ca.st

,

the causes are likely to be either too thick

cient troweling, or

coat

—

an

Cnicks running diagonally across a

jtartition,

comers of doors and window openings, are

tlie

jilaster, insuffi-

amount

of |)laster in the piugetl cati.ses whicli are easily n-miHlied in the remainder of the work. insufficient

settlrment or shrinkage of

llie

They

buiMing.

or radiating fnmi

cau.sed

by the unetjual

fre<|Uently
perp
when

the putty

is

not gjiup"*!

enough or not troweled or brushed enough, wlu-n it is |>ut on t«>o and when tiwi little sand has be«'n used. 'I'he.se cnuks anrliipjiid rrtuks.

will f>f

I'laster.

sometimes crumble,

t(K)

much

injun-.s the

.S4ind.

thick, calletl

wlu-n apparently jK'rfect and without cracks, fn)m tiM» nipid ilr%'ing or from the us*-

<'ither

Hither too

much

strength of mortar.

817

or

t»M)

little

.sand

materially

PLASTERING

22

If unclean sand, dirt, or clay has become mixed with the mortar, not only weakens the lime but prevents its adhesion to the sand no real set of the mortar ever occurs. Of course, particles, so that it

at all times,

poor materials

—sand, lime, or hair—may be responsible

for defects in plastering.

Plaster occasionally falls off even

when

apparently hard and good, if the laths are too near together, if there is insufficient hair, if the mortar is too rich or too sandy, or if it had not

been pressed against the laths with or

when being applied; of the laths under the

sufficient force

may become loosened by the springing

it

On brickwork the mortar requires pressure of floating it too hard. considerable more sand than for application on laths. Lime must have time

to set before it dries out. Therefore, to should dry slowly. A stiffer working mortar makes better and harder plaster than thin or wet material, provided, of course, it

last well,

is

thin

it

enough to clinch well to the lath in first-coat work, or to adhere and dry scratched surfaces, and to spread evenly, in second-

to brick

coat work. Stiffer mortar can safely be applied upon wet mortar than on dry; and wide-spaced lathing will take stiffer mortar than

When two

close-laid laths.

the last coat falls from the

coats of mortar have been put on, and generally because the first coat

first, it is

was not wholly dry when the second was applied.

The

coats

must

be entirely dry or quite green to be successfully combined. If possible, it is better to have the workman use makes of materials,

either

especially lime, having those properties with which he is acquainted. Attention has already been called to the fact that different makes of

hme

vary considerably in their chemical composition. It is not even same make will always run even in production,

certain that lime of the

year after year. Of course, lime that has been slaked by exposure to air or water while in the barrel, and before it is used, is worthless.

As

this occasionally

such bad material

As a

final

is

happens, it is well to be watchful and see that never added to the plaster bed.

warning, be certain that the

last coat of plaster

dried out hard and strong before any wood finish wise the wood will absorb the moisture from the swell

to

is

has

installed, as other-

plaster, causing

it

to

and therefore opening cracks that are never

be altogether closed.

All

wood

likely afterward finish should also be kept out of the

house while plastering is going on, as it will absorb moisture from the air around it. The reason that sash are not ordinarily set until after

318

ri.ASTKUIN(i th«'

j)la.stt'rin<j

is

is

ruiislittl,

luraiis*'

moisturt' as to t-aiisr the sasli lo sidt-rnl prrfi-ral)!*'

of

c-ottoii

tit

cloth, as

till

tliis

>\v«'||

tlu- \viiitii)w

than

and

it

altsorl)

()|M-iiiii^s

much

nion-

stRMiffthenetl,

window-screen

if

is

Contrary to wliat niij^ht almost as goo«l a |)n»tection

window,

slif^ht loss

to

ra|)iilly

than

artificial

!><•

«if

white-

suj>[>osed, thedrjth

a^^ainst external cold

althoiij^h the current of air passinj^

thnni;^h the cloth meshes of these screens into

re<|uire
allows of a

still

nect'ssary, l)y the a|)|)lieation of a coat

fn)st as is the tjlazed

causes a

imu-li nf the

is

if

wasiion the inner side.

and

.si»

p-MHTally c-onor ihwirs with scrvenij It

these opcninfrs wen- cIosihI l»y .s<j|id do<»rs In vcrv hatl weather the scn-en cif cotton inav Ik*

would dry

t'la/cd sash.

sli;,'htly

tli«*y

in j)la<<-.

prevfiits
cirnilation of air that ilrics phtstrrin^ lit-at, «»r

23

of heat, addint;

somewhat

and out of the house, to the exjH-nsj* for fuel

In ^o«h1 dr^'iiji; weather, dry out a j)lastered l>uildin<;. shouM he taken out and left out durinj; the
these screens

should he replaced at nij^ht or in dani|) weather, when the |)laster otherwise is likely to reabsorb moisture from the air ami so delay the

time of

its final

drying out.

If avoidable, the artificial dryiu'j of plaster

by salamanders should

not be employiil; natural dryiii}; by sun and air is. und<-r all cin-umThe salaman
is

jilaced,

and the

inci

j)laster

(|uickly itself

—especially the

with

jjas

(

riling al>ove

— but

fumes, and, by steamini;,

fills

is

the air

fre<|Uently

the cause of the rottin<; of plaster or hair, thus reducing its vitalitv and life. Heating a house to dry out the plaster by means of the regularly installed heating plant, is prefcral)le to the use of salamanders, the chief objection iti this ca.se being occasioned by the unduly nipid drying-out of wall j)laster back of or above registers and nidiators. The situation is help«'
scTcen

is

U-tween

|)laced

it

and the

plasicr.

.\

screen

may

also

Ik*

the wall over a hot-air n-gister; but tlH-n* is no einployi-il against means of protecting the plaster on either side of a partition thnuigh .*^uch plaster is Unnid lo Ik* which a hot-air or steam pi|>e passes.

strained by In-ing dried loo (|uickly. jdaster i.s fro/en when wel, it is likely to loosen up and injure The elTecIs of the whole iiiavs so that il may eventually fall olT.

.s«'verelv If

fre<'/ing are less

has (Mice

set.

troublesome

If

only

if

the wall

slightly frosleil,

Mti

is fn»/.i-n afl«'r it

is

drini and

and ihawetl inuneilialely and

PLASTERING

24

floated again,

much

often be saved, the effect in that case being not it would be if the wall had been surface-

may

it

different

from what

moistened and refloated. Plaster

Plaster mouldings

Moulding.

upon

ceilings

and walls

are less frequently employed now than a few years ago, when, espeof wall and ceiling, a heavy cornice of plaster cially at the intersection

was the common method of

more commonly

Nowadays a

finish.

cornice of

wood

is

used.

moulded plaster cornice is or screeds, are run on the ceiling and parallel strips, with their nearer the side wall, edges evenly straightened. These edges Briefly described, the running of a

as follows:

Two

are then fitted to the

mould

—a piece of metal cut out

section of the cornice outline.

fastened to the wall for guiding fitted to

The mould it,

to a reversed

run along the strips the lower edge being cut out and is

run upon them.

The plaster necessary to fill up the mouldings of the cornice may be tied back to the wall and ceiling by rows of nails driven so as to stand at about the location of its greatest thickness; while a strip of metal lath, filling in the angle upon projecting furrings, will offer the best possible clinch, and will help to reduce the thickness of the plaster

and render

its

drying and shrinkage more equable and

its

sur-

face less likely to crack.

When all is ready, enough putty and plaster are gauged in about equal parts to run the cornice down the length of one side of the room. The moulding form is then rested upon the supporting and guiding and drawn

along from right to left, pressed against the mass of mortar which is thrown into the angle just ahead of it by the trowel, the space immediately in front of the moulded strip strip against the wall,

being kept sufficiently

full of plaster

entirely at all times.

When

mortar to

the length

is

fill

out the moulding

completed, or the gauged

is used up, the mould is moved back and forth along the length of cornice that has just been run, scraping away all the plaster except that included within the outline of the mould.

material

Where hollows mould should

may

occur, the gauged material scraped off by the thrown on again at these places, so thai they

at once be

be immediately

filled

and brought up

to the right section outline

by again running the mould over these portions. The gauged putty will set in a few moments, and each side of the room or section of the

320

PLASTKlUNt; lUDiiltliii^

must

\h'

mil

iiiwi

cuniph-tt'*! or

ciiniers at tht- aii^K'S of tht-

of

tin-

nunu may

mould may Ik* separately and fitted in j)laee

Im)X, niitrnl

east

and run

The

nioidtlin;; heinj;

extra

amount

pntjectin;^ mouldinj^s

is

luii

out very rapidly. Tlif hand, or a section

fillt**!

in l>y

In- fillnl

upon the

fU>or,

sawn

in a

mitre

U|>on the wall, the joint Ix'tween the

then earefully patihe
off.

of plaster included in the thickness of extreme the cause of occasional surface craekinj^; while

hy the settlement, shrinkage, and move-

other cracks are oc-casionetl

Vnr these and other n-asons,

ment of the house frame.

erally considereil that a woo
Finally, the mouldinj;

he run over

may

its

it is

now gen-

defects of shrink-

he sprinkle
several times more, endinj; hy finishing mould may with a hrush so as to give the moulding a gloss just as on the wall it

The same

pnK-ess is repeated for dilferent kimls of plasmoulding, merely varying the metluKl to provide for the ditferent conditions .set hy circumstances, a circular niouliling aroimd the plastering.

ter

lighting outlet in the middle of the nxtin, for inslance, heing

swung

from a peg driven into the center of the gas j)ipe or outlet Ih>x. ( )ther kinds of plaster mouldings are run hy unimportant variations of the dcscrilKnl.

proces.ses

Cast ornaments are

made

.separately in

moulds, into which the

these sepanite moulds are made of jilaster pnired. plaster hardened with glue or shellac, or surfaced with heeswax, and are

Most of

is

gem-rally oile
which case the heads .should

pla.ster

.so

Ik'

countersunk ami covered

in

with

as not to show.

liXTI:RI()lv>

PLASTIiRINO

for dwellings has Keen in use has hut reii-ntly met with fav«ir in this Ill llalv, plaster, or stucco, a|)plied in large, imhroken COlintrv. a >loiie or hrick huilding, has long U-en a favorite e\|>aiise> upon

.Mlhonyh exterior plaster surfacing

in l'hiro|M' for

niethiMl

of

many

construction,

stainetl or col(»rrd

France, and

years,

<

it

l-'reipu-ntly,

and worked

Iik>.

this

|>la.s|er

iiilmlith-n'nt «'«'signs.

ii|>

iermany, plaster has

Ix-en

321

more fntpiently

.surface

is

In l\ngland. usetl in

con-

PLASTERING

26

nection with a half-timbered frame, although these countries also its use in large, unbroken, simple surfaces.

contain instances of In

modern American work,

it

is

not often that a brick wall

is

covered with plaster, as the aesthetic possibilities in the use of rough hard-burnt brickwork have now long been recognized; and when this

—the

dwelling,

cheapest it is

itself

—

brick-building material is employed upon a utilized for the exterior surface and to obtain the

exterior effect of the structure.

Plaster has been used in this country in imitation timbered houses for

some years but ;

recently

—a

treatment

much more

in large,

simple surfaces,

strips of dark wood, has

become popular

its

unbroken by the cross-barring

employment

appropriate to this country.

We

also

and stone houses, two hundred years old or thereabouts, that were covered and surfaced with white plastering; but in the most recent of American plastered dwellings, this effect possess some examples

of brick

has been simulated by applying the plaster to a wooden frame lathed with a fine-meshed wire cloth. In any plastered building, the cornices should be projected sufficiently far to protect the walls and all exposed upper surfaces of the plastering. The farther this projection, the safety of the plaster, especially in the northern

more

certain the

sections

of

the

country.

The in

essentials for successfully-wearing exterior plaster applied

modern

fashion, are:

A

well-seasoned, shrunk, and settled frame;

a solid, immovable foundation; and a carefully applied and thoroughly worked job of plastering. The framework should be somewhat better

constructed and more carefully arranged to prevent movement or settlement than on an all-wooden l)uilding. Other than this, the

dwelling to be plastered outside does not differ, in any part, from the ordinary house, until the structure has been framed and boarded in.

For

plastering, the boarding

more waterproof grade

is

then covered with a slightly better and

of paper than

if shingling or clapboarding Outside of this papering, the house is furred with strips of furring, seven-eighths of an inch thick by one and one-eighth to one and one-quarter inches wide (for metal lathing they are to be

were intended.

placed nine inches apart, for wood laths twelve inches, on centers), and the lathing is applied upon these strips.

322

PLASTKUIN'O A\i:r\i.

TIh'

The

\in

fur exterior pla.stcriii^'

Ix'.si laili

win- cloth.

I

wire

is

11

is

pndmltly

tin-

No.

In* ihinilih', >iiHicieiitly hirp- to

I'.t (

'linton

ami the mesh

allow the mortar to press through aiui completely the hack of the wire, thus prot.sover fill and ure to the elements or ilamaf^e from vater and rust, even if the pla.ster

suffieieiitlv ojx-n to clo.se in

surface should leak sufficiently to admit water hehind this covering. is also u.se
from the

consi(lere
fact that

it

is

im|>ossihle to

the hack of this lath with plastering, and j)rotect no means of certainly pn)tecting it from the jxjssi-

cover entirely and therefore there

is

of rusting. hility «)ver a story and a-half «»f Occjisionally.on a small, low hou.se of not The metal lath heomittetl altogether. may

wall height, the hoarding is

then place
and

—

opens a small crevice along each side whicli has already been mentioned as occurring in l)ack |)lastering and it is thus possible that water may enter from the hack and do con-

ever, the .shrinking of the .studs

—

siderable damage, even through the narrow space that this shrinkage The omi.ssion of the outer Iniarding aLso .somewhat injures provides. the stiffness of the hou.se, as a frame constructtnl in this way is not so well brace
the hou.se

when

.so

is Neither are the dwellers applied. the exterior weather, as the from protected completely obtained between the papering and the exterior

the iMtarding

second air-.space

This extra air-space is of a.ssi.stance in keeping the is lost. more e<|uably warm in winter and c(m)1 in summer.

plastering hou.se

In the use of metal lath, ah.vilitlf

e,s.sential

is

ing plaster surface fasteneil

held to

anv

tin-

I"

it

is

always

to l)e remi'inberetl that

protect the lath from in whatever fashion

—

This once done

nist.

anil

to

is

cnsure
|ier|M'ndicular

tin-

a

the

action of wat«'r and

p«Tmanent and

Sometiujes the metal lath

is

la.st-

winti

iron furrings of tee-irons or angles,

w(km1 frame with staples or.soim* similar fastening, allowing movement of the fn;me lo i>c< iir without affecting <»r

|X).ssible

.straining the

plaster surface,

which

is

by

this

means

disas.s(K-iate«l

("nicks an»und from, while directly sup|)orled by, the house fniine. anthus l>ut of the the the windows and angles buildings pn«venti««1 ;

.123

PLASTERING

28

more expensive form of construction, and is not now employed except in the larger and more expensive residences. it is

a

From

the use of wire lath, there are occasionally obtained small if the lath joint happens to come at a place

surface cracks, especially

where some strain it is

ing.

is afterward placed upon it, and particularly where weakened from the movement of adjacent portions of the buildFor instance, if a perpendicular lath lap is made on the line of

the edge of the

window

finish,

a crack on the line of this joint

certain to appear in the plaster, extending both

wood-surrounded opening.

is

almost

above and below the

Care should be taken

to cut the strips of

lathing so that the joint will come at least nine or ten inches on either side of the edge of the window or door finish. All furrings should also be kept away and back from all angles, internal or external, upon the walls, so that a certain clinch

may be effected by the plastering at these

important points.

WOOD LATH Wood

lath

is

occasionally used, and, in certain sections of the

It may be country, apparently with good results. employed in two ways one, in the ordinary manner, only spacing the laths somewhat

—

would be advisable on the interior of the dwelling. other method consists in laying the laths diagonally over the building in such a manner as to form a criss-cross lattice-work. In this further apart than

The

case the distance between the laths

is from three-quarters to seveneighths of an inch, so as to allow the plaster to enter easily and form a solid clinch behind these lattice openings. The purpose of the diagonal

criss-cross lattice

is

to provide

more or

less flexibility for

the wall

covering, so as to take up, without injuring or cracking the plastering, a certain amount of the movement that may always be expected

wooden-framed dwelling. This method of employing lath, by the way, is in most localities almost as expensive as the use of wire or metal in a

lath, which is probably a safer and surer material to employ. As large and as good a quality of heavy wood lath as can be secured, shoukl be provided for exterior work. Lath cracks are also then to be expected, from the same reasons that apply to interior work; while the mortar

should be somewhat softer and slower drying when used upon this material than when a metal surface. employed upon If

possible,

that, after the

advisable so to arrange the work upon the house of the some time will still elapse frame, completion it is

324

29

l'LA.STi:i{I\
iM'forr tlu" plastjT tlic

nf

iiitrriiir

t|iiriii;j tlu'

is

winter,

If tin-

u|)|)lii-
and

tin-

fniiin-

ami

lioiisr plastcn-tl

tin-

exterior

can

fiiii.slt<*
|>la.ster

in, aiuJ

Ik* l»«)iinl«'
imhUt

ai|ile
urtiiidal heat

the sprinjj,

|»n)l>-

( ahly ihe l)e.st resiiUs are to he exiMfti-tl. )|)|x>rtunity is tlien |>n)vi(le«l for the frame to shrink, settle, and eontraet. ^h)St of the \vei<;ht to Ix*

insi(h' of

|)hic-etl

surface

is

the huilihn<;

a))]>lie
is

then also

to atleet exjM-ete
than would

it

before the exterior

installe
so that iniieh less strain

and movement mav \n-

Ix*

under the

|>n)ijal>le

opjxtsite ctMiditions.

ON

iM TTI\(i

coat

fir

I

PI

\Sli.k

Exterior plaster re<|uires thn-e-i-oat work. is indis|)ensal>le when metal or wire lath

ecpiallv im])ortant over wo(m1

hitli.

This

or rou<:hene
second coat

is

A

ap|)lied.

first

The is

or seniteh

lirst

use«l,

coat should

Imt alm
i)e

thorou<;hly dry before the <;reater time ou^lit to elaj)se hetweeii tlie Ik'

applications of exterior than of interior |ilaster coals, inasmuch as it then heconn'S jM)Ssil)l«' to cut out many of the larijer and more im|M)rtaiit

cracks than have had time to

a|)jH'ar,

and

to j)atch

them before

put u|)on the huu^c Tlie second or lin>wn coat is then the less likely to crack; and, if a further extra time is allowe«| the the seconil coat

is

plasteriiif^ to dry.

final

sla|)-
it

can also he patchctl

or finishini; coat

pro^'ress aids in

<,'ivin<j

a

is

at the last

moment

put u|n)n the walls.

more permanent job ami one

before the

This slower that

is

at

the

.same time less likely to ^ive annoyance from surface cracks aftt-rwanl making' their appearance in the fhiish plastering.

The

i|uestioii

variable hen'

ais

in

of pro|M)rtion in mixin;; th«' plaster is tpiile as the ca.se of interior ])laslerin;;, and it is e4|ually

im|>ossible to n'lvv ab.solutely definite dinclions.

hilferent j>lastenTS,

each beinj; piided bv the experience obtaine
in dif-

ways of cement is

ferent .se<-tionsof thecoimtry, j)refer their individually ditTerent |)n>|)ortionin;,'

added |M'r

or mixing;

to the lime

mortar

cent of the mixture,

.shoidd be

le.vs

tlu-ir

in

materials.

In

tin- lirst ("oat.

prn|)ortions varyin;,' U'twet-n ten ."^omc that the |)lasterers preh-r

stilTened with

ci

inent than the sretind.

and first

forty e»»at

With others

llic reverse is true; uliilc, contrary to the p-neral sup)>osition, the exterior coat a|)pears to contain only that in the majority «if eji.ses amount of cement n«-<'e.s.sary to provide the lone or color that is d(*sinil

32 ft

PLASTERING

30

Conditions also greatly affect these proporadded last on a well-seasoned and shrunk

for the exterior treatment.

When

tions.

the plaster

frame, for instance,

and

far

still

The dash

from

it is

is

worked

stiffer

than when the building

is

newer

finished.

final coat for exterior plaster is generally

applied as a slap-

finish, the surface texture

being given by the throwing of handfuls of variously sized pebbles or gravel upon the fresh outer coat, thus The smaller the size of the particles pitting or marking up its surface.

employed

for this purpose, the

more

likely they are to stick

and remain

in the fresh putty, slightly tinting the surface with the color

of the gravel employed. The coloring of exterior plastering as when it is used inside the dwelling.

not sufficient consideration

is

—

if

—

any

done in much the same way As a rule, it may be said that

is

bestowed

in this

country upon the

possibilities provided by the use of color for exterior plaster work. It is agreed that the utmost care to prevent absolutely

any leakage necessary on the part of the workman in the carrying out of this class of work and it is here that the success or failure of exterior is

plastering course, the joints occasioned by the juxtaposi-

;

Of

most often hinges. tion of the offer

wood

finish

and

around window and door openings The plaster should here be an outer architrave backhand should

plaster

opportunities for leakage.

many

carefully flashed; and,

if

possible,

afterward be put on so as to cover and protect this joint. Otherwise, a key should be provided for the plastering, by cutting away or hollowing out a space near the inner edge of the wood facure, into which the may be pressed by the workman, and leakage thus prevented even if the wood, as is quite likely, shrinks slightly away from the plaster

plaster after

it

has been put in place.

The problem

of making tight this exterior plaster wall is comand rendered more difficult when it is divided into panels by a plicated so-called half-timber treatment.

In this style of design, a great number

between plaster and wood are occasioned where the wide wood boards are almost certain to shrink away from the of joints

plastering,

and where,

too,

battens in any

Thorough

impossible to protect these joints by outer applied capable of covering such an opening as may occur.

it is

way

flashing

on

all

upper exposed surfaces, assisted by protecting and broad keys provided for the entrance of

overhang of the roof eaves,

326

ri.\s'n:in\(; the piaster at

all

ami

|m r|H-iiilicuhir

3i

ln\vi-r iinri/.oiitul juiiils,

must

uiinu'

Ih- rrliitj ii|xiii.

I'lidcr

III)

c-ircuiiistaiKTs, so far as tin- lasting valiu'

coiiffrriiil, (joi's tlu' iiiixtiiri'

of {jreat can-

ii|)<)ii

play vi

a part as

iiii|M)rtaiit

(»f tlu-

tlic

work

is

f.\|M-ii(ling

tin- tli<»n>iiijli .siirfa
of

iiitorvcrv cn-virr proviy the finish, an
takiiij;

everv j)reeaution to work out

water could is

tlu'

|>ossil>lv jMiictratc

all

piiilioles

surfa<

c.

or other tlef
I'lvery

care and endeavor

directed to proviijiu^ a sohd, «'Venly workc*!, and jM'rinanent (.-oating

which

will, in

|)ortion

every

way. throw oil' ami prevent nioistim* In-ing hack of the plaster coating that vulnenihle

|M)ssil)le

into the space

ailniitt*-*!

where

its

attack

—

most enVctually

is

con<-eale
and most

to l)e

drcadc
The

exterior plaster trealment of a cenn'ut or concrete wall is u from now on will lontinue to he of rapi
a brighter surface color

is

desirahle.

treatment of concrete construction consideration.

is

'I'he

solution

Its

prohleni of the a-sthetic

one that has.

re<|uires se|)an»te

as

and

heen

hardly |)articular Hollow terra-<'otta tile is another mat«'rial that is JM-ing attempted. nKwlernlv u.se«l more and more as a .structural hase to take an exterior yet.

linish. plaster surface

The

student desiring to ohtain a wider knowledge of tin- intricate of exterior plastering, may he refcrre«l to several articl«-s pul>suhjci't For lishe
without the dwelling plastering—within and treatise

"IMastcr,

n-memher, and

in

I'laiu

.iiid

I

)e<-orativc."

— see Mr. It

consulting the latter voliuue, that

that the subject

is

workman, accustomiil from those conunoii

trcateil

to

from the

|)oint

\\ llliam

would he as well it

was

i.ssu«-«l

practice

327

to

in 1S07,

of view of an Knglish

methods and materials Munewhat

in .\uierican

«>f

Millar's

dilTcrent

EXTERIORS AND INTERIOR OF HOUSE SHOWN

IN

PLAN ON PAGE 331

PAINTING Tlic

IntrcKlucton.

first

thiii^

a

tii.iii

know

wishes to

he

wlu-tj

Tliis will ohviously (le|M'iii| a house, is the cojil. eoriteiuplatt's painting on tiic f/st of lal)or, of materials, and tin* kiml of materials chosiMi.

The <jutsi(le of a house

is paintnl, «'ithfr in whoU- or in part the interior Some houses havr tlu-ir walls partly or varnished. painteii (•overitl with shinj^les; these shinj^les are sometimes |Kiintfi|, and

luav

;

Ih'

sometimes

—

in faet,

left

unpainte
;

hut what

is calltil

the (rim

—

the boanlint; about the eaves, windows, doors, the l)ase-l)oard,

that

is,

and

eorner-jjiec'cs

staintnl

—

often

—

is

painte
Shirifjles, either

wall or roof, are often

with a ereosote stain eonsistinj; of a eolorinj; matter

or susjhmhKhI

in a litpiid ealh^l crronotc,

whieh

iliss<j|ve
isapplii-tl for the purf)oso

of preserving tiiem; and thouj^h instanees ean he eiteil in which wallshinjiles that were never slainrd are still doinj; <;ood service althou^'h

he now two hundn-d and

ijelievi-d to

lifty

years old, yet the

\\i>L'

of

creosote will undtnihtitlly prolonj; tin- lifi- of nKHlern, sawn shinf;les.as it is noxious to insirt life anil a j)owerfnl ileterrent of natural di-cay.

The

color of unpainted

new

shin<jles

is

jjenerally dislikitl; hut aft«'r

four or five years wall-shin<'les take on a beautiful, soft color. (jue.stion

(tr

of staininj; shinfjies

is

'I'he

a matter of taste.

Mo.st hou.ses are exteriorly painte<| with paint basnl on white lead Some idea of the co'^t may perhaps be jraiiuil fn)m the

zinc.

followitifj c"onsi«lerations:

Wliitc lead Icsw

coinnionly

is

— in

sold cither Rrouinl witli thi«

:i

littli- oil

to a tliick paste, or

dry state

A mixture nil,

wiiito load wit li of KM) pountls of dry K^llons of paint, weinldiiR 21.3 ll)s. jM'r unl. .\pi>ro\itiiate fiKiires an*: 15 n*s. paste lead and )>..')

make.s

">

Kallons of linseed

tij

ll).><. oil equal.s 1 ^t\\ e<|uals 7.7 ll>s.); II lbs. dry lead and 7J ll>s. oil ei|iinlH I gal. niixtun^ of 100 pounds of white zinc and S\ )!iU. oil, inaki>s U)\ i;al of

(1 gnl. oil

A

and K'>I- "! niake 13 i;al.. or <.t.*> Ihs. xine and .'i.7 ll>s whito zinc pnint weiKhin^ l.'i.'J ll>.s. l>ark-co|on>d paints iron oxides, orhers, and the like, wei^h I'Jto poutuls |M'r gallon, exact Jiunn"" i;iiitiot he given, as thi> raw m.'iterial.s dilTer >;rej«lly.

paint; 12

ll>s.

make made from

oil

l>ut

I

zinc

1

i;al.

Here shoiiU

I

Ih-

noted the dilTrrcnce U'twcen

the suc<'i>e«lin^ ones.

,\

primiiuj coal

320

is

the

tin*

I

priming

first (x)at

et>at

and

applietl to the

PAINTING wooden

clean oil,

surface;

it

diflFers

from the other coats

because the wood will soak up the

of the paint

oil

in containing more and leave the coloring matter

on the outside.

To make the

paint for the priming coat, take a gallon of the paint and mix with it a gallon of raw linseed oil. Paint described already thus made is, of course, lower in price; it is also much thinner; but

such

the absorbent

power of the wood, that the priming paint does surface as the succeeding coats per gallon. gallon of this thin priming coat covers 300 to 400 sq. ft., while a gallon of second or third-coat paint, well brushed out, will cover about twice is

not cover as

A

much

this surface; this

is

because the surface for

and non-absorbent.

but the

all

coat

first

is

Priming coats are used for both outside

hard

and

inside work, as will be described later.

The

dark-colored paints are usually cheaper than those made zinc, and if made of good materials are not inferior in

from lead and

made by the zinc and lead manumuch doubt. Some of the darkmost durable that can be applied on wood. The

durability the extraordinary claims ;

facturers are to be received with

colored paints are the chief cost of painting to locality

is,

however, that of labor, which varies according less than twice that of

and other conditions, seldom being

materials.

For

light-colored paints,

it is

better to use

raw linseed

be added, as described

pale japan dryer may either this or boiled oil, boiled

oil

later; for

oil

to

dark

being darker in color.

The

which colors,

cost

is

practically the same; also the durability.

On

inside

work may be used

either

oil

or enamel paint, as

described later, the former being the cheaper, the latter the handsomer and slightly more durable; or the wood may be finished in its natural color,

by varnishing

it

The

either with

an oleo-resinous varnish or with

wood very while white shellac varnish keeps it more nearly in its appreciably, natural color; although the latter does not prevent the natural darkening action of light, it may retard it. Shellac varnish is the more expenshellac varnish.

sive finish of the two,

oleo-resinous varnishes darken the

if

well applied.

\Miat

is

sometimes called

oil

generally consists in the application of a cheap varnish called hard oil, which is usually made of common rosin, linseed oil, and benfinish

zine.

Its

only merit

is

that

it is

cheap.

330

FIDOT acAi.E.

PLAN

FL(2)B

?.i.f.?-> y t

? ? ?

-

'p

v'f

?aET

OECOND TLGDE PLAN ocALB

y

I

f

?i

f

t;r?

? f'l

> 'r

feet

SUMMER HOME OF

DR. J. B. McFATRICH, LAKE GENEVA, WIS. W. Carbys Zimmerman, Architect, Chicago, 111.

Frame House

Built In 1906. Plau is Conditioned by Narrowness of Lot Overlooking the Lake. The Interesting Feature is the Screened-in Porch, which, by a Series of Folding Doors, can be Made Part of the Living Room. The High Frieze in the Living Room is Decorated with Woodland Scenes Showing the Lake and Hills in the Distance. Exterior and Interior Views Shown on Page 328.

I'AINTINC It

would

but iiunly oil

Im--

j)Oii.siltlf

to apply lu'itlitT

would, however, make

it

finish;

imli'ttl

to s;itunite the \vo(kI with oil,

and

|)aiiit

nor vuniiiih,

would

this

and

the wo«j*l
Ik*

truly

an

and

dinj^y,

would nadily retain dirt, ami is a pnietiee sehloin followed exeept sometimes on floors esix-cially kitchen floors and sink shelves.

—

—

These are It is

intervals oile
at frequent

and turpentine.

boiletl oil

till"

j)urposf

of this Instruction l'a|Mr to ih-scrilu- only

{:«km1

It will readily he understtKxl, and will apj)roved methods. in practice, that these methods may \w ahhn'he ohservetl certainly viatetl hy the omission of some details that are here sj)ecifieti as desir-

anil

For instance,

able.

it is

diflicult to get interior finish .siindpajxntl or

nihUeil lutween coats, even practice.

No

four.

if

so contracted; hut this

is

the

ri^'ht

Two

coats of varnish often have to scr\e in the place of The methods one, however, neeils to he told these things.

herein descrihed are not lu.xurious or extravagant; they are, on fairly and we are not considering temp<jrary giMxl hou.ses, truly economical; structures.

uncommon to find part of a hou.se, as the living nK)ms, varnish, and the kitchen and pantry paintinl with oil

not

It is

fini.shed

in

which are lighter in color and more easily renewe
harmonize with the furnishings; and hathrooms are almo.st always done in enamel for .sanitary conThe taste and inclination of the owner are to Ik; considerations.

hecau.se color effects are desired to

sulted in regard to

all

these matters.

PAINTFIRS' Pigments and

\ chicles.

solid .suhstance with

ti

lii|uid

SUPIMJIIS

Paint

is

a mi.xtun"

which, when

with a hnish or otherwi.se, will adhere and evnjKinition, or

tough

film,

part, the

an

oil

When

'i'he finely

divided solid

is

The most couunon

a

on a

(inely-
surface

a short tinu- fonn

in

more connnonly hy oxidation

vrliirlr.

I'f

sj)ri-ad

— a .sonu'what

hy hard and

caUetl the piijnirnt: the liipiid

vehicU-

is

linsntt

oil.

.solvents) froni

ohtained hy pressure (or cxtnictitui hy spread out in a film an
This

is

fla.\.see»l.

air, lin.seeil oil is ct>n-

verted into a tough, leatlu n-,
water and

all

eonnnon

.solvertts.

r^r^t

This <-hangr

is

hnMjght

alxiiit

hy

PAINTING absorption and chemical union of the oxygen of the air, whereby the weight of the oil is increased about one-fifth or one-sixth. It is therefore a mistake to suppose that oil paint gets dry as whitewash does, the of the Instead of that, it gets heavier. by evaporation liquid.

There are some other vegetable oils which have this property in some degree, but none which are used for paints to any considerable extent; some are used a little for artists' colors. Linseed oil should stand at least a month or two before usino-. should then be perfectly free from sediment or cloudiness; if it is not so, this is a sign that the oil has not been properly aged, and such oil is not fit for making paints. In this natural state, it is called raw oil; It

and the price of linseed oil as commonly quoted refers to raw oil. oil is this raw oil which has been heated, usually to 450° or 500°

Boiled

F., with the addition of a small

amount

of oxide of lead or oxide of

manganese, or a mixture of the two (occasionally some other lead or manganese compounds are used). Boiled oil is darker (browner) in color than raw oil, but differs from it in that it dries five to ten chiefly

times as rapidly.

A

thin film of

raw

oil on a glass or metal surface dry at ordinary temperatures in five or six days, so as to feel no longer greasy; but boiled oil will do the same in a or half a

will

day

Oil dries best in

warm, dry weather and out The pigment is mixed with the oil by

This

is

usually done

by power,

day.

of doors. stirring the

two together.

in a vessel called a paint mixer.

The

mixture should then be run through a paint mill; some paint mills are of steel, but the best have a pair of mill-stones, between which the paint is ground and most thoroughly mixed. Paints manner are much better than those which are mLxed

niLxed in this

only by stirring. and pigment, paint sometimes contains a volatile thinner, the most important thinners being Turturpentine and benzine. pentine is a well-known essential oil, volatile, at about 320° F., Besides

oil

boiling

but evaporating at ordinary temperatures when exposed to the air. Benzine is a mineral oil, lighter than kerosene and heavier than gasoline; the kind used- in paint and varnish is called "62-degree benzine," its specific gravity being 62° on the Baume scale for liquids

lighter than water. tine, 7.2 lbs.; oil

Linseed

and 62° benzine,

oil

weighs 7.7

6.1 lbs.

makers and dealers on the basis of

332

But

lbs.

per gallon; turpen-

linseed oil

7.5 lbs. per gallon.

is

sold

by the

PAINTfN^;

A A

ilrytT, is

dryer

in oil,aii«l

somr

ill

is

f«inii,

an

cssriitijil

in^nilit-iit

asii soluti<J!i of sui-li material in a mixture* of oil,

oil

jKiiiit.

tur|x-iitiii<-,

and

Im-ii-

usually of such streiif^tii that an atlilition of from 5 to 10 cent of it to a raw-oil |)aiiit will mtke it ilry in from six to twelve It is

ziiif.

|H-r

of

a coiuiKdiiKl of K-ail or niaii;piiu'st' (i;nirrally Unlij, solulile is usually soKI, umliTtlir iiaiiR' ui paint dnjtr ar paint japan,

hours sulHeieiitlv to he carefully handled. to use, until they

I'aint.s

have stood four times as

The

tinue to harden for months.

lonj^

are not
a.s

this;

and they condark in

stronj^est dryin;; ja|)aiis are

more injurious to the diinihility of the jxiint than those which are paler, es[H'cialIy if the latter do not contain n)sin. The huver should always ask for a 'guarantee that the dryer is free color; hut such are

Not more than n)siii, if j^reat durahility in the j)aint is needtil. 10 [HT cent of aiiyilryer or japan should ever he use
from

In house puintinj^, the white pi<,Miients arc the most important, Infause they are the base of all li<;lit-colorcd paints. The most lead. This is sold cither as a dry imj)ortant white j)ii;ment is irliitc white as or li-ad. which is made of (more commonly) paste j)owder, (H) ll)s.

with

dry wiiite

l)f)iled oil

pif^ncnt;

leail

and 10

make

to

and with a

ll)s.

a white

linseed

oil.

This can

White lead

j)aint.

fjiven (piantity of oil,

more

than of any other pij^uent, except red lead.

It

of

is it

has

l)e

thinnetl

a very heavy can he mixetl jjreat opacity,

It is discolored hy ^a.ses ct)iitainin<j sulphur, covering j)ower. hecominj^ hrown or hiack; and unless exjx).se
f)r

with the

oil for

.some timi a

ll'hitr zinc is

—

a year or more.

somewhat purer white than

whiti- lead; not so

Three coats of lead arc reckoiu'
ad, aftir<'X|X)sure to the air fur a Imi;^ time,

on

its

surface, and

becomes dry ami |M)wdery

rlialk.i.

of two parts of h-ad and ono of zinc is much VAnr-lvad, however, is the name of an entirely dilfen-nl |)ii;ment, by fiirnacinj^ ores containin;; alM)ut eipial parts of lejul and

\ mixture

in

which the lead

is

the liability to (urn

not (juite

.S4»

pure a

present as a sulphate.

brown

if

\\\\'\\.v a.s

ex|M»s«'«l

to

is friH"

/.iin-.

frtin

sulphur pises; it is .sjiid to In* It is a coiii|Kkni(ively new

the prc«'e«linj;.

ana

This pigment

likitj.

made

PAINTING pigment, but the others.

is

into use, being somewhat cheaper than another white pigment of considerable merit. these pigments may be adulicrated with

coming rapidly

Liihopone

Adulterants.

is

All

barytes, or with terra alba (sulphate of lime), sometimes with whiting These adulterants are powdered minerals. (carbonate of lime).

Barytes is a good pigment, so far as protective action goes; and terra alba is thought by some good authorities to be unobjectionable; but whiting is injurious. All of them are transparent in oil, and lessen the opacity or whitening

power of the

paint.

these white paints, colored paints are made by adding tinting colors, of which the yellow is chiefly c/tro7;ie yellow, or chromate of lead; the blue may be either ultramarine or priissian blue; and the

From

is chrome green, a mixture of chrome yellow and prussian blue. reds are (in house paints) made from coal-tar colors, and most of

green

The

them are now fairly fast to light. Some dull yellow colors are made from ochers, which are clays tinted with iron oxides, roasted and ground. These are permanent

colors.

dark-colored paints may not contain lead or zinc at all. The deep yellows, greens, and blues are made from the colors already named as tinting colors, none of which are entirely fast to light; the

The

dark reds and browns are chiefly iron oxides, which are a valuable class The blacks are either lampof paints, very permanent on wood. black or drop-black (bone-black) and other carbon colors; and these are often added in small quantity to secure some desired tone or shade of color.

The

zinc

and lead pigments have some action on

oil,

and

in their

considered the best practice to apply thin coats; but the dark pigments do not act on oil, and, of these, thick coats are best for dura-

case

it is

bility.

Paint and Varnish Brushes.

recommend

A

brush that has only a low price

prove a poor investment. If properly cared for, brushes last a long time, and it pays to have good ones. The first sign of a good brush is uniform quality from outside to center. Inferior to

it

will

brushes have inferior bristles in the middle, and some poor brushes are actually hollow. For ordinary oil painting, the bristles on a large

new brush should be stiff

be

five or six inches long,

as can be found ; they will be flexible

alike.

334

uniformly

flexible,

enough anyway, but

all

and as should

PAINTING Imislu's an- round, flat,

I'aiiit

out-sitk'

nnlinury Imish with bridled

whvu

i»r

A

uval.

calh-*! a

is

jHnind

favorite brush for

brit.ih,ii la rj^e,

round

inchrs long. Such a bnish shuulil Im* a "hridh*" hring a piwe of c-onJ wound around

it is

new

—

to sliortcn thoir t'tfiHtivc K-ngth; as tlic hristh-s Ixt-ome

thi"

off,

what

is

hristles six

stiff

tlu' hristles

worn

work

inches wide)

hri(ii«is

may

hi-

A

rtinuvc-d.

21-inch oval hnish

a highly satisfactory tool to

('2k

visv in

general painting, and is the brush recttniniench-d by the paint cununitte*- of the American It is worth noting that this c«jinmittec, S
made up

e<|ually of expert paint manufacturers and ex|XTts employe*! the consumers, unanimously agreeil that no larger brush than large by this

should be u.sed

The

in

making

j)aint tests.

is common for outside work; mav be had of the liest (lualitv, thev are heavv and the workman who uses such a brush will not

use of brushes five inches wide

but wiiile such brushes

and laborious brush the used,

it

better.

to u<.v,

j)aint sufliciently to get the best result.

should not exceed

A

3^.

brush

i-s

inches in width; and three inches

is

gotxl 21-inch oval varnish brush

for all large

work

in either

is

a most excellent brush

The

paint or varnish.

If a flat

painter should also

have a gof roimd or oval brushes, called sash tools, of different smaller sizes, for

more

delicate work, such as .sash

and frame

jjainting.

Stiff-bristle

brushes, which have b<>en worn off short, are suitable for such work as

For varnishing large surfaces, flat bristle brushes nibbing-in filling. 21 inches wide are goinl; also similar ones 2 inches, 1\ inches, aiitl 1 inch wide arc useful.

For flowing vaniish,

.Ml flat brushes should it

is

nece.s.sary to

have

have chiseled

inlires.

thick, flat, camel's-hair

inches in width, although most hou.se rumiing u\) (o be brushes done with not over '2\ inches wide. varnishing may bni.shes,

'.',\

Besides paint Itrushes, the smdihiiuj hrushis and one or two

workman

will

m-e*!

p.-iinler's diistiiuj

.souu*

onlinary

hruslus, to have the

.surface pn)j>erly cleaned.

Steel-wire brushes, with

stiff steel

wire instead of bristles. sha|Ht|

like MTidtbing brusln-s, are used for cleaning off old cleaning structural metal work. These are of various .steel

wires

jire «»f different

pjiint

and

si/^vs;

and the

for

lengths and sizes, hence differing in stiffness.

They may Im* had at hanlware ston-s. Hair and bristle brushes nuist U- kept dean Care of r.ruslics

33a

PAINTING

8

and

soft; this

can be done by care and faithfulness.

They should

not be allowed to become dry with paint or varnish in them. To prevent this, wash them out in oil or turpentine as soon as you are through using them or they may be left in the paint or varnish for a ;

They may be kept over

few days.

night by wrapping them very they have been used in a slow-drying material in this way they may be carried from one place to another. Brushes should not be left to dry with even clean oil or turpentine in them; if closely in

paper

if

;

they are to be put away, they should be well washed first with soap and water, then with clean water, then hung up until thoroughly dry.

A

In use, brushes are best kept in what is called a brush safe. deep wooden pail, with nails driven in its sides at different distances

from the bottom, and with a close cover, makes a good receptacle The brushes have holes in their handles, or loops of

for brushes.

cord tied to them, and are hung on these nails; their bristles dip some turpentine or oil in the bottom of the pail; they are so hung

into

that

they do not dip into the liquid above where the bristles project from If brushes are left the binding. standing on the bristles on the bottom of a vessel, they soon become one-sided and distorted in shape. Tin brush-safes may be bought of any large dealer in brushes.

A brush which has dried with paint or varnish in recovered by soaking it in a non-alkaline varnish-remover. in time soften it so that it may be used again, but it is not

it,

may be

This

will

improved by

such treatment.

Brushes used

in shellac

No brush is good unless it is

alcohol instead of turpentine or benzine. clean. Fillers,

Fillers

are

of

two kinds

should be washed out with

—paste

and

liqiiid.

Paste

are something like a very thick paint, and are composed of some solid powdered substance, usually silica or powdered quartz, mixed fillers

with a quick-drying varnish thinned with turpentine or benzine. is applied to the dry surface of the wood with a stiff, short-bristle brush, or is put on with a clean, white cotton cloth, and well rubbed into

This

the pores of the wood.

wood felt.

fillers

After half an hour or so, the surface of the

with a wad of excelsior or a clean cloth or a piece of A liquid filler is a quick-drying varnish; and most of the liquid on the market are cheap rosin varnishes loaded with dryers,

is

wiped

off

and should never be

used..

Paste

fillers

cases.

336

are the best in almost

all

TAIN riNC UOlSi:

and

All wIikIow

Inside \S (trk.

l'\l\IIN
«l<M»r

tlu-y art- lo

with paint or varnish, .should rrcrive a mMHi c*oat of paint niadi- with some cluaj) pi^'mcnt, such as inin oxidi-, and ljoil«d <»il, 1k' fiiiislutl

to

a|)|>liid

shop ders

hatk of the

till-

«le('av.

if not, it should he applietl as s«K)n as pracof white lea
coat in the shop,

raw

if

|»ossil»le;

I'he

ticahU'.

oil,

oil,

with very

little

are to he

evaporates. with j)Utty.

made hy mixing

lead j)Uttv,

or hv adding

ilry lead

to

This kind of

sistencv.

common

and

is a.s

The

filled

is

Turjientine

])i;,Mnent.

priming coat, hecause the object As .soon turiH-ntine

to

fill

this

is

not a ^xmI thinf;

hest putty for this pur{M)se

a

little

leiid

j)aste

putty,

it;

a

raw

oil

cracks, joints,

ami

a

until

white

is

with dry white lead, it is of the right con-

hardens <|uickly as compartnl with

i)Utty

A

is

hardwood

in

the jM)res «)f the wixKl.and »lry to the touch, all holes

the hest for this purpo.se. on interior woodwork, as it should not he used scratch

hnjuj^ht fnjni the

fniini-, hcfort' tlu-y art"

house; this prevents tlu- absorption of moisture ami hinIf they are to he painted, they shotild receive a priming

tlu'

t«»

stick, suitably

is

steel putty-knife

almost certain to

shaped, slutuld he

nail-holes should he canfully

filled.

u.setl.

.\11

.Ml knots

and .sappv places should he varnished with slu-llac varnish; this preThe shellac vents the pitch and moisture from attacking the paint. hefore the priming coat. The applied where it is needed, to he time should coat get <|uiti'
shoidd

l)e

po.ssihle;

This shoidd contain a considerable amount of turpentine. If no turpentine is used, the surface is likely to be glossy, ami the next coat of |)aint will not adhere well; but by rej)laeiiig part of the t>il with we get what painters call a flat <•<)(//— that is, «)ne which i.s

.secontl coat.

turpentin*',

not glossv;

if

this is

ma
|)aste

lead or

any

|)ast<'

paint,

it

<'«n

be proainf«TS prefer one-thini oil and tw«w thirds turpentine.

be allowe
This

is

to

for inside if

dry thoroughly; drv enough to hamlle, then at

least four

.should elapse before the next coat

and as much mun- time as

work

takivs ten

it

is

This coat

.sh<»ul«l

times

l<-n li«)urs

addHumal

a giHxj giMiemI nilc; If {\\v fmi.sh .shoidd be allownl.

ap|)lied

|)o.ssible

only.

hours for the paint to U*

337

;

thi.s is

PAINTING

10

to be ordinary oil paint, the next coat may be paint, thinned with about half as much turpentine as before, or with no turpentine at all. In the latter case, when the coat is thoroughly dry, it must be carefully is

examined, and,

if

glossy,

it

should be rubbed with something to take

off the gloss; curled hair is often used, or a light rubbing with and water. Then the final coat, which has no turpentine in it,

pumice may be

applied.

But

if

the finish

be with an enamel paint, the second coat,

to

is

when

quite dry, should be very lightly sandpapered with fine sandpaper, and the third coat should be of like composition to the second,

same way; then the enamel paint is applied. For a really when this is quite dry, it should be rubbed down with curled hair or pumice and water, and another coat of enamel put on. treated the

first-class job,

This may be

left

with the natural gloss

if

desired

or

;

it

may

be rubbed

with pumice and water to a flat (dull) surface. Painting Plastered Walls. Old plastered walls may be painted with oil or enamel paints as though they were wood, remembering that the priming coat will have almost all of its oil absorbed by the plaster. New plastered walls do not take paint well, on account of their alkaline character, which gradually disappears with exposure to the atmosIt is well to let a wall remain unpaintcd at least a year. But phere. if it is necessary to paint a freshly plastered wall, the wall is prepared

by some painters by washing

it with a solution of sugar in vinegar, the sugar uniting with the lime to some extent; or more commonly by washing it first with a strong solution of common alum and then

—

—

with a solution of soap. After this is dry, it is washed with clean water, allowed to dry, and then painted. The alum and soap form an

compound which closes the pores of the plaster to some exand tent, prevents the lime from acting on the paint. Outside Work. Exterior paints are more elastic, as they need insoluble

to

be far more

lasting,

exposure to the

than those used on

sun and

thing else does.

rain,

interiors, since the effect of

destroys paint

more than almost any-

Paint on the interior of a house will

last

almost

indefinitely; but on the outside the best paint is not very durable. The surface, if new, should be cleaned by ])rushing; knots should be

shellacked; after which the priming coat should be applied. This may be the same paint which is selected for the finish, only thinned

with boiled

oil (or

raw

oil

and dryer), using one

338

to

one and a-third

rAiNTiNf;

giilloiis

mav

of

oil to eiifli

Tlir niisoii

gallon of paint.

imt he ustti as a

is

priiiu-r,

11

that

tlu*

why onlinarv

wimhI ahsorl)s

jMiint

leav-

tht* oil.

as a ctinparatively iiori-adhesivr |H)\v
ing the

applie
so much tlu- better. ilapse l)etwicn these coats, If the old Repainting;. paint has heeii on a long time, to Ik' jH'rmeated

hy minute cracks, which admit m<jisture

it

is

liahle

to the surface

now we

paint over this, the new which shrinks in drying, tends to pull <»ff the old paint, and of paint, If the oKl pjiint is in this state, course the whole peels off in patches. This can Ikit must he remove
and loosen the

If

j)aint.

Vor this work a paiiilrr'.s torch is ilone hy burnimj off. which is a lamp burning alcohol, gasoline, or kcro.sene, and

retiuiri-tl, is .so

con-

stnicted that a blast of flame can be directe*! against the surface.

This

the old paint, which is then imme
melts or

.scjftens

by heat .so that it can be .scraped off. In .some cases to remove as much as jxj.ssibic with a steel bru.sh; this a .scrubbing bnish, with vigon)Usly used, will take (

well,

and

ste«-I oil'

it

is suflic-ient

is

a brush like

when

win-s instead of bristles, and,

the loose ])aiMt.

however, is not always in this condition. If it adhen-s be cleane
)ld paint, it

may

wlii'ii it

(piite

it has fade
tlie

needed. well to paint the trinj— that is. the window-casings, dtM)rbefore painting the Ixnly of the casings, corner-pie<es, and the like house; then the paint can i>e applieil to the Hat surface's more neatly Paint should be appli««d in thin to be done. than is otlu nviscIt

is

likely

CfMits, Wi'll

brushed on;

n-H-ntnint angles while diHiciilt to

it it

is

not umisual to M-e |taint

is still

go«Ml

brush the paint pn>perly

in thosi-

dilTen-nce in diimbility lu-tween a thin

330

come

|)lnc'«'s.

|»!iinl

llowitl

Then'

fnmt

«>IT

on Hal surfaces. UvaUM* i.s

it

was

a gn*«t

on with a

largi*.

PAINTING

12

flat

brush, and one of proper consistency well brushed out with a brush size. In all painting on wood, it is desirable to brush it on

medium

of

with the grain of the wood; and by painting only a few boards at once, we may avoid laps by painting the whole length. Rough surfaces hold paint better, and more of it, than smooth. A gallon of paint will cover, one coat (on a painted or well-primed surface), about GOO square feet,

not flowed on, but well brushed out in a thin film.

coat will not cover

more than 300 or 400 square

The priming In

feet to the gallon.

measuring the outside of a house for surface, make no deductions for doors and windows; if the trim is to be painted a different color, from one-sixth to one-third of the paint will be required of that color. coat of dry paint is Paint should be stirred frequently while using. from -^~g to T.oVo of ^^ ^nch in thickness.

A

Roof Painting. oil

Roof paints should contain a

larger proportion of dryer (or none at all). think that the addition of ten to twenty per cent of fish oil to a

pigment than other paints, and

to

Many

less

paint for roofs is advantageous; fish oil greatly retards drj^ing and prevents the paint from becoming brittle. Tin roofs, if new, should

be thoroughly scrubbed with soap and water, or with pieces of harsh cloth, such as burlap, well wet with benzine. They may then be painted.

Paint dries relatively fast on roofs; but as a roof paint slow-drying, plenty of time must be allowed between coats. roof should receive three coats. treated the

same way.

]\Ietal gutters

Do not forget that new tin

have

is

very

A new

and spouts are

to

or galvanized iron

be is

very thoroughly scrubbed, even though it looks perfectly clean, and then rub the paint on well with the brush. Metal spouts will usually be painted the same color as the wall of the

difficult to paint;

it

house.

is it

Sometimes shingle roofs are painted with fireproof paint. This not really fireproof, but considerably retards the spread of fire, after has become thoroughly dry; when fresh, it does not even do that nor ;

have much

has been on a year or so. It may be made by adding to a gallon of any good paint about a pound of

does

it

effect after

it

powdered boracic acid. A\Tien strongly heated, this material fuses and forms a sort of glass, which keeps the air from the wood. It is after

a time washed out by the

Canvas

rain.

roofs are prepared in the following

340

manner:

The canvas

1*

A I MING

13

down, care

l()-<)unce (luck is often iisiil) is first iiailttl

(

draw

it

tight

;

accumulate

to

will

it

a

common

form a

to

thoroui^hly wet;

show some

it

shrinks, and

practice to paint

it

tion to all other practice; hut

has heen accustonutl to the

canvas shows wrinkles on

A

desired.

to

all

the

while

little

Then

wrinkles

is still

it

some wait

Ik-

is

STRICTI

is

It is

an

e.\ce[>-

The

writer

Ix-iuf?

dry.

and has not found that the

dryinj^, while the results are all that

well-paintetl can\as roof

very durahle and

ini.

can

Ix;

siitisfactory.

MITM.

a more perishahle material than woimI, arwl more diflicult rej^ilar expenditure for maintenance, wiMxlen

is

Without

paint.

hriilfjes last

than

lonj^er

steel

thousand vears old; and in)n oidy over furnaces and the

ones; there are wocMlen roof In-ams a

i*oofs

like,

are

.so

short-lived that thev are usetl

where wocnlen ones would take

The

painting of structural steel is therefore injj)ortant; antl diflicult, if wc are to judge by results.

it

is

lire.

also

prej)aration of the surface. When clean and dry: and then we soak the surface paint wo<mI, with oil, so as to have the paint hound to it in the most intimate

In the

first

place

comes the

we have

we it

allowed

the canvas

tlisii|)|M-ar.

wet, this

luitil it is

latter niethiHl,

l>\!NTI\(i Steel

wrinkle or fold.

larj;e

taken to

In-in^

wrinkles, hut these are not to

Iron and steel, on the other hand, always come to' us dirty, o.xide; and as the surface is not |)on)Us. the |)aint

manner.

and covered with

does not jjenetrate it, hut has to stick on the outside the best way it can. If we paint over the dirt and .scale, and that ever comes olf, the jKiint

comes

off

is actively rusting, and we paint over the made slower, hut it does not stop. perhaps moisture cau.se rust; if we can ket-p tluiii away, the metal

with

it; if

the metal

rust, the corrosion is .\ir iiiid

will last; hut, e.\|)ose
thing

unfortunately,

to the

weatlur

in |.ainling

metal

if

is

in

to

an
all

'/«/ ///'

jidiiit

tin

thr iintal, not

on an

inter-

niiiliate coating.

There are onlv two wavs

to clean sferl

perfectlv.

One

is

l)V

10 to 20 jht cent sulphuric aei
jtickling

it

in dilute acid

(ii.sually

of thivsjind-hlast. Neither of iluvse pnM'e.s.ses is availidtle to theonlinary who nmst do the next l)«'st thing. This is to remove alvsolulely painter, l''irst clean olT the dirt, if any, all dirt and all Iikksc scale and oxidi-.

'M 1

PAINTING

14

with brushes, as

would be cleaned

it

ofp

any other surface. Then, oft" all the scale which will

with scrapers and steel-wire brushes, clean

come

If there is

off.

any new

scraped out and cleaned

off.

rust (not mill scale),

This

is

it

must be well WTien

indispensable.

this is

done, immediately paint it, before it begins rusting again. One of the most popular materials for a first coat is red lead in

This must be mixed on the

oil. it

will

harden into a cake

From 30

long.

gallon of oil

to

—not

on the metal;

spot, shortly before

in the pail or

can

if

it is

used, because

allowed to stand very to be mixed with each

33 pounds of dry red lead is than 28 in any case. This is

less

immediately painted put on in too thick a coat, it will run and be uneven. others boiled oil it does not make much difference

if it is

Some

use raw

which

is

oil,

;

The

paint dries rapidly; and as soon as it seems hard, a second coat of the paint can be Red lead is different applied.

from

all

used.

other paints in this, that it will finish hardening just as well the air. This is because it does not oxidation, as

away from

dry by

other paints do, but by the lead combining chemically with the oil, In the opinion of the just as water combines with Portland cement. writer, red lead should have one or two coats of some good paint, other

than red lead, over it. But red lead is not the only first coating which may be used. Any good paint may be used a good graphite paint, or other carbon paint, or some of the varnish-like

—

coatings containing

linseed oil

and asphaltum which are made

important, in using any

for the purpose. It is of these, to let plenty of time for drying elapse

between coats. Not

than two coats

less

is

permissible,

and three are

desirable.

Projecting angles, edges, and bolt and rivet heads are the places first show rust through the paint. This is partly because the

which

brush draws the paint thin at such places. To overcome this, it is now becoming common practice to go over the work after the first coat,

and paint all edges for about an inch from the edge or angle, and all bolt and rivet heads, with an extra or striping coat; then, when the second coat goes on over the whole, there is the equivalent of two full

coats ever^'where.

Painting on iron, as on wood, should be done in dry weather, it is not very cold— at any rate not below 50° F. Full,

when

heavy

and well brushed cracks and corners.

coats should be used,

the paint into

all

342

on.

Care must be taken

to get

PAINTING Ak.M>ll

\

A

varnisli

that

is

on

film, uliicli,

a

lii|ui(l

15

litatlc to In-

appliitl to a surfaci- in a thin

to tin- air, lianlrns into a pnitiftivt- coating

rxjx).siirr

usually glossy and almost transparmt.

is

classes

—spirit and

Thcrt- arc two principal

oleo-rr.titioii.s ranii.s/us.

the most inijxjrtant, arc made by ilissolvinga resin (or sometimes some other suhstancej in a volatile solvent, such as alcohol. They tiry by evaporation, the solvent going ."^[)irit

off

varnishes, of which

ser\'c
thin flakes.

It

in the following

Put

th»>

may

means

as a mechanical

Shellac

the surface.

of

resin spread out in a thin film, the li(|uid or vehicle

and leaving the

having really

.v//r//«r* is

a

is

be

of sprea«ling the resin over

which conies on the market

ri-sin

in large,

dcnaturtMl (or any other) alcohol

di.s.solved in

manner:

alcohol in an eartiicnwan- jar, and wi-igh out five j)()Unds Just before leaving at

shellac for each gallon of alcohol.

gum

and gently drop the slullac, little by little, into the jar Do not of alcohol, then put on the cover and leave it until morning. on anv account stir it. In the morning the fiakes of .shellac will be night, carefully

soaked and swollen; but if you had stirred them in, the night before, they would have stuck together in linnj)s. Now, during the day, stir the ma.ss with a wfxiden stick once every hour or so; do not put any metal

in

it,

espet-ially iron;

barrel of shellac.

Hy

one iron

the next

nail will spoil the color of a

whole

— — morning perhaps before the shellac

be rea«ly for u.se. It does not make a clear solution, b<.>cau.se the gum .shellac contains .some wa.x, which does not di.ssolve, and so the will

varnish

is

milky or cloudy;

it

is,

howevir, ready for

As the

u.se.

the jar shoidil be kept coven.il; and after made, the varnish should be put in gla.ss lM)ttles or clean tin cans.

alcohol

is

volatile,

it

is

of shellac gum, the best being known by but there are others nearly as good, 'i'he common brownish y«'llow, and is calh-d oniiK/r sin liar: this is the natu-

There are many grades th<' lett«Ts

shellac

nd

is

i>

(';

shellac color.

chlorine;

l)Ut

cf)urse, the

ginn

will,

•

Tbnro

it

White shellac

is n«)t

of

.s«)

good

is

matle from this by bleaching with

(|ualify as the unbleacheil;

it

has.

tif

advantage of Ix-ing much paler in
N<>T«.- Hy <">m«' i)nlnior«, tho i«Tm •varnlHh' |h ni'Vrr u»«l lo Imludn nhpllMS. hiiwrvor. ii<> v»Utl. (ibjncilvn rrawui (or tbiiH lltnttlU|{ iho uiMof the U^rm.

l4,

34a

PAINTING

16

vamish may be thinned with Shellac lessens

its

alcohol,

too often adulterated with

is

value.

Damar five or six

is

This

is

easily detected

a white resin which

pounds of

is

and often

common

this is necessary.

rosin,

by a chemical

which greatly test.

—

soluble in spirits of turpentine

resin to a gallon of turpentine. It

is

the most

nearly colorless varnish we have, but never becomes very hard. It is used to a considerable extent as a vehicle for white lead and zinc, to make a very white enamel paint. It is not durable if exposed to the

weather.

More important than

spirit

varnishes are the oleo-resinous var-

nishes,which consist of certain resins dissolved in linseed

oil, the mixture being thinned with turpentine or benzine. In making these, the resin is put in a copper kettle and heated until it is thoroughly melted then some hot oil is added to it, and the mixture cooked until the whole is thoroughly combined. The kettle is then taken from the fire, and ;

when partly cool, the turpentine is stirred in. The resin makes the film hard and lustrous, and the oil makes it tough. Thus the larger the proportion of resin, the harder and more brilliant will be the film the larger the proportion of oil, the tougher, more elastic, and more durable it will be, and the slower it will of jNIost the color of varnish dry. ;

comes from the

The

pale

gums

resin; the paler this is, the paler will be the varnish. are higher in price than the dark ones, but are no better

any respect except color. Dark varnishes may be just as good (except in color) as pale ones in fact may be better, for the dark resins are often harder and better than the pale ones of the same sort. The hard and quick-drying varnishes are suitable for furniture; the in

—

medium,

for interior house-varnishes; the slow

and

elastic, for

exposure

to the weather.

Varnishing. better,

if

The wood

necessary to clean

it,

should be dry. For this reason to avoid washing as much as

it

is

possible,

using sandpaper instead, which will also make it smooth. Of course the carpenter is supposed to do this, but the painter must not neglect

on that

account. ^Mien in proper condition, it first receives, if it is an open-grain wood, a coat of paste filler. The open-grained woods in most common use are oak, chestnut, and ash. The woods classed as it

woods are white pine, maple, birch, yellow pine, whitewood, cherry, and sycamore. These latter do not need If filling. filler is used, it should be well rubbed in with a short, stiff brush; and close-grain

344

PAINTING wlu'M

has

it

set,

in fifteen

say

haixlful of e.xcfl.siur,

rul)l)iiiji

ti>

17

tliirty iniiiiites,

it

ami

acniss the ^'niin,

is

nililKil

ruhhiii'^;

to force the filler well into the jx)re.s of the woo
(iff

with a

hanl, mj as

Then

it

should

stand 24 to 4S hours.

When

j)URhased,a paste filler is too thick to Ik? used with ahru-sh, and must l)c thinned with ttirpentuie or U'lizine; at the Siiiue time it

may Ix* stained

to

any desired cohjr with an

oil

or varnish stain,

'riir-c

stains can he j)urchase
stain the wimmI; hut

it

is

common

|)ractice

to finish in the natural color.

Stains usually re<|uire a ^(mmI deal of thimiinj; before usinj;; the amount Water stains arc seldom of thiiminf^ will determine the
used, as they tend to raise the ^rain of the wood. In cleaninfjoll" the filler, he careful to clean out corners and mouKl-

hardwocMl sticks; ings, usm<; for this purpose, properly shapcil use any steel

Where rooms it

is

do not

tool.

are to he finished in the natural color of the wood,

nevertheless a

common

cherry or

practice to stain the window-.sashes; a Fillers are .sometimes is often U-sihI.

stain

lijjht maho<;any used on close-grain woods; hut this

is not advisid)le, as they tend to varnish from getting a good hold on the wo(mI. the prevent Next comes the varnishing. Window-sills, jamhs, inside hlinds,

and other surfaces exposed

to the direct rays of the sun, are to

he

woo
treate«l as exterior

out of account for the present. first coat of varnish; apply it. as

wood, hrushing dust free

(/.«•.,

it

'I'lie

rest of the

woodwork nreives

its

much

as possible, with the gniin of the The varnish ought to dry out well in a thin coal.

so that dust will not sti
it)

over night

;

Imt at least

When dry, it shouKl he ruhlH-*! elapse lielweeii eoats. withcurl«-
five (lavs

sill

II

lid

coat of varnish will adhere j)ritperly; a lietter result will he had if it is (HI The se<-ond coat is treat»"«l like p;i|ier. lightlv .santlpapered with the

lirst.

The

third

is

not siind|)apereil. Imt rulihed with eurletl hair; may In- left widi the natural gloss, or. ifpn*-

thefourtln>r linishing coat ferred.

it

mav Iw

ruhl>e«l with line

pumice and water

t«»

a sn)(Ktth,«hill

Kor this pur|Mts«' the varnish tiealers .sell felt,al>«)Ut an inch .surfa«-e. lean water; a little «lry |»iuniee jiowder is tliick, which is well wei in <

345

PAINTING

18

this. The varnish must be it; and the rubbing is done with is before this and hard attempted. Varnishing, if properly dry quite much time must be allowed for each that slow is is, work; done,

put on

coat to dry thoroughly. The varnish which

is used on interior woodwork should not dry should dry enough over night so that dust will not stick and in twenty-four hours should be hard enough to handle freely;

too quickly; to

it,

it

a chair, for example, were varnished with it, it would not be for a week. It should, however, finally become entirely safe to sit on it

but

if

perfectly free

from tack, which

it

will not

do

if it is

a rosin varnish. At

not probable that they will ever be lower) varnishes for interior woodwork are sold, according to color and quahty, at ranging from $2.50 to S4.00 a gallon. It is in the highest present prices (and

it is

prices

degree inadmissible to use a cheap varnish for undercoats theouter coats A good varnish that dries too quickly, such will crack if this is done. ;

what

as

is

called a rubbing varnish, or one intended for furniture, has

It is economy to use a good not the durability needed for this work. in a mind house which was properly varvarnish. The writer has and has been nished eighteen years ago constantly occupied by a large

family, yet the varnish

is still

in fair condition

papered and one new coat applied, it

is

well,

possible for

;

if it

would be

Cheap

were

like

new

lightly sand-

—as good

is

not used on exterior work, but

as

rosin varnishes never look

even when new, never keep clean, and deteriorate rapidly. Interiors are sometimes finished with shellac. Shellac.

varnish iors.

a surface to be.

it

it is

This

a good varnish for inter-

All varnishes containing oil darken the color of wood; but white is comparatively free from this objection; at any rate it does it

shellac

less than anything else. Orange shellac is a dark varnish, and even white shellac darkens with age to an appreciable degree. Orange

shellac

is

more durable than white, and should be used wherever

admissible, rather than white; but shellac for this service.

described

—

it

—

five

pounds

it is

If shellac is

usually necessary to use white as heavy as has been

made up

to a gallon of alcohol,

and

this is the

standard

should be thinned considerably with alcohol before using on inte-

woodwork. It must be applied in thin coats, and given plenty of time to dry. It is very deceptive about this; it appears to be dry and hard in an hour, and it is hard enough to handle freely; but if we apply

rior

coat after coat, even six hours apart,

346

we

shall find that the

wood

is

PAINTING liiially

cuverttl with u

hut tn)uhle.

The

waxy

nu*^s

wliuh

19

U-

will

llie

.sourff of

nothing

hrst roat sinks ntpiilly into thf wimxI; a stfoml coat

apphttl six hours hitcr; hut aft«T that, allow two days at least Shellac makes a very thin coat; so it is necessiiry to apply a larije numlnT of coats, at least twice as many as of oleoBecioise resinous varnishes, to get a suflicient thickness of coating.

may he

hetween coats.

of this

an expensive

lalM)r, shellac is

durahle.

treatment of

'I'he

it,

finish; hut

it

handsome

is

as regards ruhhing, etc.,

tiie

is

jmhI

s;ime

as has heen descrihcd for other varnish. \'arnish makers usually a
w(mmI shoidd he

where

it

Of course,

should not he used.

hefore shellacking, the.s;ime as for other varnish. \'arnish does not, however, wear well over a heavily shellackeil sur-

Shellac

face. little,

filled

makes a

and wearing

wmxl very has heen well varnished

gocwl floor varnish, discoloring the

fairly well,

.\fter the floor

—

it, ver)' thin coats, applied rather fre<|Uently say every one to will keep the floor in fine eondition four months, f.ccording to use

with

—

;

and he

after applying

tiry

wide, in a

enough

one of these thin coats

to use in

hrush, and a

flat

few mimites.

an hour.

(of thinni-il shellac),

This can he

ap|)lie(l

it

will

with a very

man can go

over the Hoor of an ordinary room Shellac hnishes should he wasluti out with alcohol

iimnt-diately after using.

I'xtcrior Varnisliing. doors than within, so that it al>le

The

materials.

are not giMnl enough.

much more

praeticahle to use

conditions, in fact, are In the

first

j»lace,

more

.so

rapidly out

elastic


and dur-

.seven* that the In'st

do not use any

filler

on

Do not use prohahly crumhie an
exterior work; .shellac;

\'arnishes
it

will

r.se only the U'st spar rarni.ili, such as is matle for vannshhli>ter. ing the spars of yachts; fill the woo<| with it; sandpa|H-r lightly iM'tween coats, just enough s«i that each sutvct-tling ctiat will take

hold well

;

fitiish

with a coat well (lowed on; and leave

natural gloss, whi<'h

is

more

it

ladling than a nihU-il surface.

with

This

it.s

is

the treatnn-nt for hand-ntils. outside d*Mirs, inside hlintls, window.sills

rails

and jamhs, and everything «'X|)os»'«| |i> the din-et sun. Handand outside d(M)rs should he refinisln-tl everv vear; vaniish will

347

PAINTING

20

not last on an outside door more than one-twentieth as long as it will on an inside door. Never use interior varnish for outside work.

ENAMEL PAINTS Varnishes are all more or less brownish yellow or yellowish brown. Therefore a coat of varnish applied over a paint obscures and changes its

color to

some

To overcome

extent.

much

this as

as possible, the

mixed with the pigment, as a vehicle. In this way the pigment comes to the surface and displays its •color. These paints, if made with good varnish, are durable; the method of varnish, instead of

oil, is

If application has already been described. necessary to thin them, it with spar varnish instead of oil; a good interior varnish may be used, but it injures the flowing quality of the paint somewhat.

do

White lead and zinc are sometimes mixed with damar varnish. This makes the whitest enamel paint, but it never gets very hard, never has

much

easily applied,

luster,

and

is

not very durable.

It is

very white,

is

and dries quickly.

A

NEW VARNISH

FINISH

A method of finishing open-grained interior woodwork, which has been practiced for a few years, consists in first staining the wood with a water-stain dyeing it, usually and then, when it is dry, filling the the pores of the wood with a paste filler which has been colored

—

—

by

addition of a pigment. For example, the wood may receive a stain of any dark color, and the wood-filler be mixed with white lead. This

shows the open or porous part of the grain

in

white on a dark back-

combinations of color

in the stain and filler, By using very beautiful effects can be produced, and this finish has been used in some of the most handsome and costly public and private

ground.

artistic

buildings.

Thus, if a room is to be decorated in green, the woodwork can be made to harmonize with the prevailing color. An oil stain must not be used on the wood, as it will not work well with the filler. The colored filler applied and rubbed off in the same way that any paste filler is used, and then the varnish is applied over it in the usual way.

is

FLOOR FINISHING The primary

trouble with floors

is

that people walk on them. If all. Four coats of varnish.

they did not, there would be no trouble at

348

i'AlNTING ...

oi

11

havinj; an

j.-iiiii,

iuinilritlth uf

an inch,

aij;;;rf;^iitf

21

of less than om* om*-

tliiikm'.s.s

nut last indcliniti-ly under the

will

uf nuil-

\vi>ar

shcxl hfcls. Pn)l>alj|y tin- siniplest treatnu'tit for Htjors shoiilil

jKiint

contain a

varnish; an ordinary usihI,

dry

oil

twelve hours.

in

projjortion is

paint

must he heavily

it

larj^e

painting thenj. The hard oleo- resinous

is

of a

not hanl enough.

If

an

oil

[Kiint

char{;e
(Joofl

Hour

(juiclvHlryinj;

jiaints

is

should

are in the

niarki-t.

wood, however, are not usually |Kiinte4l; they may If tlu-y areof oak or other o[X'n-^niine«l

Fl(M>rs of ciioice Ih'

either varnished or waxetl.

woo«l, they nuist he

with a jjaste filler; otherwise the varnish is Floor varnish is <|uicker in drying, and than interior hardiT finishing varnish, hut should not he so hanl as to to aifplii-d directly

he

hrittle; ruhhiu}];

this is tlone

lilled

the wocmI.

varnish

with an

oil

is

too hanl.

If

the floor

stain hefore varnishin;^;

has previously heen varnished, so that the stain wood, the stain may he mixed with the varnish,

if it

he

is

to

is

a floor which

staiue
will not

penetrate the althoiij^h the effirt is

not then so good.

Floor

and

is

wax

is

shellac; then the

when

made

not

of heeswa-X, hut of a harder ve<:etal)le wax,

sold hy all paint ilealers.

it

is


fl(H)r

which

ruhhinj^ with a clean for the pur|M)se.

It

The

wax may he will

he

in a

Hoor should receive one coat of

ruhluHl on with a

few hours,

it

may

stiff

he

hrush, and |)olishe«l

hv

or with a heavy, wei<;hte
or six coats have l)een a|)plied; after this a little of the floor wax, thiinied if necessary with turpentine, should hi- applied often enou;;h

keep the floor looking w<'ll. .Alkalies lished with a |N)lishing to

hrush, it

is

is

the handsomest surface than can

so slipjMTy that

the w
Interior trim

This

)ld lliH)rs

ohtainetl for a

(hut

not

hand-mils)

which

it

is

fliM»r;

hut

It

d«)es not disct>lor

is

.sometimes wux-

finish re<|uires a gotnl deal of care, as

catch dust; otherwise (

h(«

somewhat dangerous.

is

it

it

is

likely to

harnlsiime and durahle.

re<|uir»-

cli

aiiing

and revarnishing should have

the old varni.sh or paint removed hy u giMnl vanilnh-miiovrr, tme of the niiNleni .sort, fre*- from alkali. This is {Miinttil over the surfac-e, and,

340

PAINTING

22

after a short time,

remover

removed with a

scraper.

The

last of the

varnish-

taken out with a rag wet with turpentine or benzine, care

is

in the room or any neighborbeing taken that there is no fire of any sort will not only take off the old varnish, but the old filler This room. ing also; and the floor must be treated like a new floor. Any stains on the

treated with a hot solution of oxalic acid, one part to ten the stains disappear, wash well with clear water; let

may be

floor

of water;

when

the floor dry a day; sandpaper; and it is ready for varnishing again. removal of old paint or varnish by a liquid varnishremover is applicable to all varnished or painted work. The outside

This treatment

—

—

of a house could have the old paint taken

oft'

way, but burning

in this

off cheaper and quicker. These varnish-removers are mixtures of benzole, acetone, alcohol, and other liquids, and the best of them are is

patented.

ALUMINUM AND BRONZE

PAINTS

Radiators and pipes are often painted with aluminum or bronze These consist of metallic powders, in fine flakes, mixed with paints.

some varnish

—usually with a pyroxylin varnish, which

is

a thin solu-

a variety of gun-cotton in a suitable solvent, generally acetate of amyl. If one of these paints which smell somewhat like bananas becomes thickened in the can by evaporation, it can usually be thinned tion of

—

—

with acetate of amyl, if some of the special thinner cannot be had; brushes can be washed out in the same. A good aluminum paint is durable, even exposed to the weather.

two certainly

One

coat

is

usually enough,

so.

GLAZING House

painters

setting window-glass;

are usually expected to understand the art of it is not difficult to learn. Glass is classified as

sheet or cylinder glass

and

plate glass.

Sheet glass

is

made,

at the

by blowing a quantity of glass, first, into a hollow globe; then, by more blowing and manipulation, this is stretched out into a hollow cylinder perhaps a foot in diameter and five feet long; this glass works,

cylinder (whence the reheating,

is

name

"cylinder glass")

fiattened out into a sheet,

after annealing,

it is

cut

up

is

cut open, and, after

whence the name "sheet

into convenient sizes.

350

It is

made

glass;" of two

PAINTING thicki..

ami

...

^

uniform. Wirt,

these

more or

is

it is

first,

oiu'-sixtii'iitli

of an inch;

l)Ut it (Iocs

wavy in

its

surface;

ami

in n*s|>ect

second, and third ijuality; in American

marked "AA," "A,"

are usually

^ades

or

less irre},'nhir

as

"jradetl

alxjiit

is

an inch;

not nni [H*rfiftly contains .streaks, huhlilcs, and specks of

onc-cij^hth of

All sluft jjhiss

and

to this

which

thick,

.,iiifjlf

(Iniihlt thick,

23

aiul

f^lass

"M;" and anylhin;^

Forei^i glass is not thus p)on'r than "B" is called stock sheets. his own Single-tlnek markitl, each maker having arbitrary marks. alxjut 2S hy 34 inches; doublethan is for sizes not usiMJ greater glass thick,

up

40 by

to

For larger

<)().

siz«'s, j)late

glass only

is us***!;

but

of course either plate or double-thick can be use
if

desireil.

Plate glass

cast in j)lates; the

is

iron table, about

feet

1')

wide and

2.")

lifjuiil

glass

feet long,

and

is

[)oure
sm(M»the
out on an

down

to a

uniform thickness of half or five-eighths of an inch by j)assing a roller over it, like n)lling pie-crust; after this it is ground «lo\vn with sand, of an inch emery, and polishing powder to a (piarter or five-sixteenths in thickness. is

also

more

It is

therefore

nmch more

perfjft.

Cr}'stal is a very thin plate glass,

and

is

usctl

costly than sheet glass, but

where ordinary plate

the finest of

all

window

glass.

about one-<'ighth of an inch thick,

too heavy, as in movable siish. It is There are two grades of plate gla.ss, is

as glazimj (for windows) and silverinr/ (for min-ors), the latter In the first place, the sa.sh is prepannl for the glass. best. the being It must receive a coat; if it is to be painte
known

priming white lead and boiled linseed turjM-ntine adilcfl; al()ne.

If

it is

if it is

to

oil,

the mixture liaving very little or no it is jjrimiil with Iniiled oil

be varnished,

not priine
draw

Next, the glass is litte
oil

wheel cutter, the handle.

If well

being a

little

shar|w
and are

The

replaceable. plate gla^s

latter

made, the wheels may be

is

wheel cutters are generally u.sed on .sheet gla.s,s; but cut only with a diamond, which makes a er cut.

are kt'pt wet with kerosene; the workman has a little Ixttthor cup of kero.si-m* on the ImiicIi, and dips the wheel in it. The glass being cut to the right size, a layer of putty is spnail,

The

wlui

Is

with the putty-knife, along the recess

351

in the .sash

where the

gla.ss is to

PAINTING

24

and should always be done. omitted but it absolutely must be sash with pine uncommonly done with all hardwood sash, metal or metal-lined sash, and for all This

rest.

is

called bedding the glass,

not

It is

;

and

plate

is

glass

crystal glass ;

and

it

ought to be done

gently pressed into place, after which

in all cases.

Then

the

fastened with glaziers' No. 2 points are used on

it is

which are triangular bits of metal. single-thick, and No. 1, which are larger, are used on double-thick 'points,

glass; they are put in 9 to 12 inches apart.

They are driven, not with a hammer, but with the thin side of a two-inch chisel, the flat side of which lies on the glass, the edge of the chisel away from the surface so as to avoid scratching it. The chisel is also useful for adjusting the position of the pane; if it is smaller than the sash, it is so placed that when the sash is in its natural upright position the pane of glass will

rest with its lower

edge bearing on the wood.

placed,

if

chisel

held over this crack, and with

is

The

points are

com-

which bends easily; and when the pane is properly there is on one side a space between it and the wood, the

of zinc,

monly

is

made

its

edge an indentation or crimp which has already been

in the little triangular zinc point

driven; this crimp prevents the glass from sliding back against the wood. This is the reason zinc is used for the points; it will bend. Steel points are sometimes used for plate glass, because of their greater

strength, the glass being heavy.

To

drive through the sheet metal of

metal-covered sash, steel slugs are used ; these are about ^^g inch thick, about I inch long, and -^^ inch wide at the wide end, triangular, and sharp-pointed. There is a machine for driving points, but except on small glass set in soft-wood sash.

The

it

is

not

much used

glass being properly secured

by points, it is ready for puttythe set the sash up in a nearly vertical ing. professionals on an the is easel; position glass puttied on the right-hand side and across the bottom; then the sash is turned the other edge up, and the

To do

operation

is

this,

repeated.

This

The most important

finishes the

work.

things about glazing are to use a sufficient

number of points and to made of whiting, which is oil to

give

it

use good putty. Ordinary (pure) putty is pulverized chalk, mixed with enough linseed the consistence of stiff dough. The workman can make it

from these materials with his hands; everyone can make his own putty. As a matter of fact, however, the putty of commerce is made by ma-

552

I'MVnVG fliiiurv;

and

also, us a

matter of

Wdiiltl sofni

It

atlnltt-rattil.

fact,

25

it

is

in ^nieral

as tlion^li wliitin^j and

uhominably were

lirjsti-d oil

inatiTials clu-ap t'liouj^li; and in reality [)Utty can Ik* sold for alnnit three cents a {x^nnd, or sixty dollars a ton; and a dollar's worth will pntty all the glass in an ordinary house. Pure putty, however, is almost impossihle to get. Marhh- dnst is sul)stitute
and a mixture of alH)Ut half.

It

rf)sin

is

and mineral

the use of this

oils for

the

miseraMe

tenths of the tnmhles with windows.

oil,

and the

stuff

c
reducetl

which causes nine-

If the glazier

cannot he sure of

his putty otherwise, he should make it himself. The best putty for glazing is a mixture of pure whiting putty with one-tenth white lead putty. This makes it set a little more <|uickly, and it hecomes harder. Pure white lea
remove

it

in

case of breakage of glass.

If the glass has not been biildeil in putty, it is customary to go around the indoors side of the glass, and crowd st)me putty into the

crack between

it

and the sash.

This

is calle«l

harkinr/ the glass. I^irge

are held in place with .strijis plates of plate glass are not puttie
and the moulding

is

backed with putty.

053

REVIEW QUESTIONS. PRACTICAL TEST QUESTIONS. In

the

numerous

foregoing illustrative

sections

of

this

Cydo[>c«h'a

examples are worked out

in

show the application of the various methods and principles. AccompanyiuR these are detail in order to

examples

for practice

fixing the principles in

which mind.

will aiil

the reader in

In the following pages arc given a large

number

of test questions and problems which afTortl a valuable means of testing the reader's knowledge of the

subjects treated. They will be found excellent practice for those preparing for College, Civil Service, or Engineer's License. In some cases numerical answers are given as a further aid in this work.

ns5

i

j

R

1

\

:

I

t>

!•:

N

Q

\v Till-:

KLKCT R 1.

Explain the

2.

Ill

ca.sf

a

1

1 .1

s

K1

C W

I

i'

!•

I

<

<

i

>

xs

» !•

K*

XO

I

.shows cxcT.ssivc lrakaf(f, or a

and

locate the trouble

Descrihe the construction

;}.

1-:

•

I

tlirrc-\vin> .system of wiring.

te.st

how wouM you

circuit,

M

' (

aiu'l

use

j;rouiiil

or

.sliort

ren)e
(if

outlet-lxjxes.

4. What is the principal ditlerence hetween alternating aniJ (lirectK'urrent circuits, .so far as concerns the wiring system?

5.

Compare

the advantages of the two-wire

systems of wiring. (). I'nder wliat gi-neral heads are ajjjiroved

and three-wire

methods of wiring

cla.ssified?

A

7.

amperes

at

single-phase induction motor is to he suj)plieil with 2o volts; alternations 12,()()() per minute; power factor. S.

220

The

transfonner

No.

1

is

200

feet

from the motor, the

line consisting of

inches iK'tween centers of conthictors.

wire,

fonner reduces

The

tnin.s-

has a capacity of 30 amperes at 220

in the ratio 2,.")()(),

'

250 and, when delivering this current and voltage, has a resistance-Iv CalF. of 2. per cent. jxT cent, and a reactance K. M. F. i>f

volts,

M.

.'>

')

culate the drop. s.

What

table

(I'.se

and chart.)

are the distinctive features of the dilVcniit kinds of

natal conduit? K. 0. Suppo.se |)ower to l>e deliven-d, delivered, 2.2(M) volts; distance of transmi.ssion, :{(M)

No. 00;

wire,

distjina"

.7; fre(|uency, in jM-r

cent of

10.

on as

to

11.

W.; F. M. !.').(H)0

F. to

Ih'

feet; size of

Iwtween wires, 21 inches; |)ower factor of load. Calctilat*- line lo.ss and «ln>p

KM) cycles [ht .second. \\.

M.

I',

delivered.

In installing A.

('.

(I'.se

circuits,

table

and chart.)

what r»'<|uin'ments an-

placing of contlui'tors in conduits? I)«'S(Tilw the mainifactun-, use, and

insist«t|

till-

the dilkrent kinds of

armored cable.

.157

s|><'eial

advantages of

ELECTRIC WIRING Which

Describe three different methods of testing?

12.

is

to

be preferred?

What

13.

conditions determine whether a two-wire or three-wire

system of wiring should be used? In locating cut-out cabinets 14. requirements should be

What

15.

cuss

is

and distributing

centers,

what

fulfilled?

"knob and tube" wiring?

Explain

its

use and dis-

advantages or disadvantages. How far apart should insulators be placed? 16. What tests should be made before an electric wiring equip17. its

ment

is

finally

passed for acceptance?

Give reasons.

20.

What What What

22.

Discuss the advantages of running conductors exposed on

18. 19.

regulations govern the use of fibrous tubing? is meant by mutual induction?

are the advantages and disadvantages of overhead linework as compared with underground linework? 21. Describe and illustrate by sketches proper methods of supporting and protecting conductors. insulators.

23. Illustrate by diagram, proper and improper methods of grouping conductors of two two-wire circuits. 24.

What dangers

are inherent in the use of moulding?

What

precautions should be taken to avoid them? 25. Describe the proper methods of laying out branch circuits, (a) in fireproof buildings; (b) sketches.

26.

following

What methods classes

factories, etc.; (c)

in

wooden frame

buildings.

Give

of installing wiring are best adapted for the

of buildings,

(a) fireproof structures; (b) mills, finished buildings; (d) wooden frame buildings?

What

is skin effect? Its bearing on the problem of wiring? In selecting runways for mains and feeders, what precautions should be taken?

27.

28.

358

REVIKW QUKSTIONS ov

TTXta

ELKCTRIC 1.

HcrnJiocx

etc:

ok

ir

I'TXG.

State the current, voltage, candle- jxnvi-r, and efficiency ot most conunonly used.

the incandescent lanip 2.

AVhat do von understand by the

'•

sinasliinir

point

"if

main points of diU'erence hetween the thri-t forms of arc lamp mechanism. ^[ention the three principal parts i»f the Nernst lamp. 4. 3.

(live the

5.

Describe with sketch the anti-j)arallel systeni of fcedin<;.

G.

Prove the law that illumination varies inversely with the

square of the distance. 7,

AVhy

is

than incandescent >5,

arc

li«^ht

photometrv a mon-

ditli^Milt

problem

'

Calculate the illumination three feet above the floor at

the center of a room IS feet square and 12 feet hi«;h. lif^hted by four lO-candle-power lamps !• feet above the floor at the center of the side walls, assumini; the coetlicient of retlection to be It.

What

material

is

.'o

.

used for the tilanient of incandescent

K.xplain why. From the curve given in Fig. 4, ilelermine the etlicieiicy V Jiich coi re.-iponds to the tt-mjK'rature of 1 ;}()() C"entign»de. 11. W'liat is the olijeci of ilouble carbons in an arc

lamj)s?

10.

lamp?

):!.

What What

1

l)escril»e the liunsen IMiotonieter.

I'l.

I.

IT).

residencuri IG.

is is

meant by mean

candle-power? the function of the heater in the Xernst lamp? sjtherical

lii)wdt>ert the lighting of public halls dilTer

from that of

?

Why

cannot platinum wire be used for

incandenCM'nl lamps

{

300

tlu<

tilament uf

ELECTRIC LIGHTING In a direct-current arc lamp, which carbon bu) ns away

17.

the

more rapidly ?

How

18.

are arc

lamps rated

?

What

are the important advantages of the two-wire 19. distribution ? of parallel system Name and describe the most desirable standard for pho20.

tometric measurements.

How many

21.

measurements should be taken

mination of spherical intensity

in the deter-

?

What

is meant by flashing? Explain. Define emissivity. If the voltage of an incandescent lamp be increased 4% 24. above normal, what is the effect on the candle-power, efficiency

22.

23.

and light? 25.

the

Explain

methods of 2G.

Cooper-Hewitt

lamp,

stating

two

the

starting.

Compare

the open and enclosed arc lamps.

the positive carbon placed above the negative in a direct-current arc lamp? 27.

Why

28.

Sketch and

name

the different

forms of incandescenf

filaments.

lamp

Under what conditions can

29.

be used 30. 31. 32. cent

is

What What

Why

is

be replaced

lamp

in

lamp

the function of the arc

lamp mechanism?

are the advantages of the three-wire system ? is it necessary to exhaust the bulb of an incandes-

lamp? At what point 33. 34.

a 3.1-watt incandescent

?

in their life should incandescent

lamps

?

What

the object of a resistance in series with the arc constant-potential direct-current systems? is

35.

Name

the advantages of the Nernst lamp.

3G.

What

sort of

lamps and of what candle-power should be

used in residence lighting ? 37.

Give the

38.

What

stant-potential

candle-power

characteristics of the

M'ill

Cooper-Hewitt lamp. be the external resistance on a 110 volt con-

system,

if

the load consists of

?

360

437 lamps

of

16

KKV

I

!•:

ON

W

'r II

•

(J

!:

I

ST

K MlTlUKi'T

I

(>

Xs

CK

PLASTKRINCi I)f>(ril)c the

1.

wood

Of what

2.

retjuirements 3.

for

prDpcr

int'tlnMl of spaciii;,',

ami joining

iiailiii;:,

lath.

materials

is

of each to insure

Compare

mortar

gmxl

\Vliat are the

comixjsttr;:'

results?

the relative advantages of metal and wcmkI lathing

both interior and exterior plastering. •1.

How

o.

^Vhat precautions are absolutely necessarv

are estimates for lathing and plastering

made? the i)lacing

in

of metal lath? If

().

wood lathing

used on exterior work,

is

how should

it

be

laid? 7.

When,

8.

Describe

if

ever, in

mixing the mortar

is

wire lath preferable to expanded metal? the process of slaking the lime and

detail

for ordinary interior plaster

work

in

dwelling-

What

precautions are to be ()b.ser\'txl? ."Should mortar be used as soon as mixed?

houses. 0.

question

Di.scuss this

in all its b«arings.

10.

How

11.

If

would you mix the mortar

lime

is

for e.xttrior

work?

not thoroughly slaked, what trouble

is

likely to

develop?

What will b<- the etlect of u.siug too much lime in mixing too much siind? What are the e.s.sentials for «lurable exterior plastering?

!_'.

njortar? i:!.

1

1.

work. I.".

th«' relative advantages of three-cojit an«l fwiwojit of work are three coats always nece.vijiry? what kind In In interior work, what precautions must U- observetl in

laying the

l)i.scu.s.s

.succe.s,sivc

In exterior

coats of plaster?

an

1

work?

REVIET\^

QUESTIONS

ON THE SUBJECT OF

PAINTING 1. is

Wliat

is

raw and

the difference between

boiled oil?

\^lien

one preferable to the other? 2.

What would you

and varnishing the frame dwelling? 3.

interior

How would

consider a good brush outfit for painting

woodwork and

exterior finish of a

you make your own putty

a satisfactory grade? 4. Describe the

princii)al ingredients

if

modern

you could not buy

used as figments.

As

vehicles. 5.

6. 7.

8.

What

are thinnersf

Dryers?

Fillersf

How are painters' brushes kept How are paints adulterated?

in

good condition?

Describe the process of mixing the successive coats of

paint for ordinary interior (not floor)

and exterior woodwork.

process of preparing the woodwork and applying the successive coats of paint in ordinary interior (not floor) 9.

Describe

the

and exterior work. 10.

of

What

points require particular attention in the repainting

an old job? 11.

12. 13.

Describe the process of painting a plastered wall. Describe the material and methods of work in roof painting. What is enamel paint? How would you do a job of

enameling the woodwork, say, in a bathroom? 14. Describe in detail the process of painting structural metal. 15.

How are varnishes classified?

16.

Describe the method of preparing and applying shellac

varnisn.

362

INDEX The page numbers

of Ihia

vulumt

will be

juaud

al

the

buUum

pages; the numbers at the top refer only to the aectton.

Page

Altcrnatlng-curreni clrcuiw

uj the

INDEX Page

D

Page

INDEX aK<1

li'iiii III

t

II

'II

rcKular rpfl«>rtlon unit of liu'anilcM'i'iii

laiii|>->

urruiiK«'n>fnt of lani|M

csrboa i-omparlson of dIfTcrpnt types of tlbirihiitliin of IIkIh

i-flUiency of Intfiuilty fon.stant.s fur

tyiH*. compurt-ain of MiltiiKo

and caiMlU'iHiwfT

Insulators. »ir run fX|KJM-ity

ron-stant^

InttTfhanBcable arc Interior pla-stcrinR Intrin.sir l>ri|{litnr!vs

Irrrgular reflection

on

INDEX Page

Page 171

Single-pitch skylight

Plastering

320

Skin

finish

312

Skylight work

scratch coat

311

bars, various shapes of

166

work two-coat work

310

construction

163

313

curbs, various shapes of

167

plaster molding

rough

three-coat

Poles I'

Polyphase circmts

Power

patterns

166

63

shop tools

166 171

Skylights

140

distribution

163

80 27

Porcelain insulator

52

effect

172

double-pitch

R

172

extension

flat

173

hipped

228

RakinK moldings Rating of arc lamps Reactance e.m.f. Reactance volts

171

single-pitch

114

Slaking of lime

55

Soldering joints

55

Special lamps

Residence lighting

303 85 121 121

mercury vapor

calculation of illumination

150

plan of illumination

150

type of lamps

150

Resistance e.m.f.

55

Resistance volts

55

Rigid conduit, wires run in

Moore tube

123

207

Standing-seam rooflng Steel armored cable

16

Switchboard

65

11

Roman

234

moldings Roof mensuration

Table

193

arc lamps, lighting data for

roof

194

armored conductors

18

hipped roof

195

conductors, sizes of in fibrous conduit

25

188

conduit

flat

Roofing

160

corrugated iron

212

single wire in

12

flat-seam

197

three wires in one

13

metal

192

two wires

soldering

202 189-191

tables

drop

193

tools required

one

13

Cooper-Hewitt lamps corrugated sheets, measurements of

207

standing-seam

in

S

in a.c. Unes,

data for calculating

flaming arc data

140

flat-seam rooflng

189

gem

Scratch coat

311

Greenfleld flexible steel conduit

Series distribution system

140

intrinsic brilliancies in

163

163-294

work

225

cornice

metallized filament lamp data

Meridian lamps. Illuminating data

281

metals, meltlnt; pfiint of

236

moldings, sizes

rooflng

188

skylight work

163

—For page numbers

15

of,

866

light

110 for 156

115

required for vari-

ous sizes of conductors

Moore tube

see fool of pages.

148

of a 25-candlepower unit data

miter cutting

106

candlepower

per square inch life

curved moldings

Note.

57 134

302

Sheet-metal skyUght

214

enclosed arcs, rating of

Sand

Sheet-metal work

159

data

22 126

INDKX Pagp Tubl. N>rii>i lumii iliita IMili- (lattt

ri-UwllnK power. n-Iatlvo rcHldi'ntv liKlitliiK (lata tIkUI

i-iin
t'liuiiii'ltxl

rdoHoK. MtanUliiK-M-ain Nkin cfTcct, (lata for cakrulatliiK

tantalum lamp data I

in (ilutc (lutu

tunK-
lamp data

VDltaKt*. firects of clianKi! In

Tantalum lamp Tcrno plate

r
TcsitInK clertrlc wiring

Threo-wiro system, electric wiring

TunKstcn lamp Turret Nash

Two-wire, electric wiring

V'oltaKe

and candlepower

Voltmeter

W Water-tlKlit outlet box

Wires run concealed

In

conduits

armored cable flexible

metal conduit

Nnie. — For page numbers see foot of pages.

PiM(«-

i

i

683017

.f.