Md Preboard 2011

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MACHINE DESIGN, MATERIALS AND SHOP PRACTICE

SET A

INSTRUCTION: Select the correct answer for each of the following questions. Mark only one answer for each item by marking the box corresponding to the letter of your choice on the answer sheet provided. STRICTLY NO ERASURES ALLOWED. Use pencil No.2 only. MULTIPLE CHOICE 1. A thin hollow sphere of radius 10 in and thickness 0.1 in is subjected to an internal pressure of 100 psig. The maximum normal stress on an element of the sphere is A. 2500 psi C. 7,070 psi B. 5000 psi * D. 10,000 psi 2.

In designing a cylindrical pressure tank 3 feet in diameter, a factor of safety of 2.5 is used. The cylinder is made of steel (yield stress = 30 ksi) and will contain pressures up to1000 psi. What is the required wall thickness, t, based on circumferential stress considerations? A. 0.75 in. C. 3 in. B. 1.50 in. * D. 3.75 in.

3.

A flywheel weighing 6 kN has a mean diameter of 90 cm. The maximum speed of the flywheel is 7 rev/sec slowed down to 4 rev/sec during the shearing process. Determine the energy released by the flywheel. A. 7856 kg-m C. 9872 kg-m B. 8145 kg-m D. 8241 kg-m *

4.

When measuring a drill for A. margins * B. flutes

5.

The tool used in precision work to smooth or enlarge holes is called a: A. round out C. reamer * B. drift pin D. protractor

6.

Which of the following chisels would be used for cutting oil grooves? A. diamond-point chisel C. round-nose chisel * B. cold chisel D. hot chisel

7.

Which of the following is not a cut of file? A. smooth C. half-round * B. second cut D. bastard

8.

Which of the following is the smallest size drill? A. # 80 * C. # 1 B. # 60 D. # 0

9.

Two parallel shaft connected by pure rolling turn in the same direction and having a speed ratio of 4. What is the distance of the two shaft if the small cylinder is 8 cm? A. 10 cm C. 18 cm B. 12 cm * D. 20 cm

10.

What modulus of elasticity in tension is required to obtain a unit deformation of 0.00107 m/m from a load producing a unit tensile stress of 50, 000 psi? A. 34.5 x 106 psi C. 46.7 x 106 psi * 5 B. 46.7 x 10 psi D. 4.67 x 106 psi

11.

Determine the bursting steam pressure of a steel plate with a diameter of 12 in.a and made of ¼ in steel plate. The joint efficiency is at 75% and the tensile strength is 55 ksi. A. 3, 440 psi * C. 3, 430 psi B. 3, 437 psi D. 3, 427 psi

12.

What is the working strength of a 2 in bolt in a packed joint when the allowable working A. 12,400 lb C. B. 15,500 lb D.

size measure across the: C. shank D. point

which is screwed up tightly stress is 11,000 psi? 18,700 lb * 22,500 lb

13.

Which of the following is the largest size drill? A. A C. Z * B. X D. XX

14.

The size of a drill is stamped on the: A. point C. margin B. shank * D. flute

15. Which of the following safety precautions should be pouring babbitt? A. operator must wear goggles B. the surface to be babbitted must be free of moisture C. the surface to be babbitted must be clean D. all of the above *

followed

when

16.

Which of the following safety precautions renewing a flange gasket? A. drain the line thoroughly B. tie down isolation valves C. isolate the section to be worked on D. all of the above *

followed

when

17.

Before installing a A. flange faces are B. flange faces are C. isolating valves D. old gasket is in

18.

On a standard wire gage: A. #10 is larger than #5 B. #25 is smaller than #20 *

should

be

new flange gasket be sure that the: painted absolutely clean * are open place C. # 1is smaller than #2 D. #30 is larger than #25

19.

Which of the following tools would be most useful when taking leads on bearings? A. dividers C. micrometer * B. outside calipers D. center gage

20.

The cutting action in on both stokes in A. Open side planer C. Double housing planer B. Pit planer D. Universal planer *

21.

The straddle milling is done by means of two A. Side milling cutters * C. Plain milling cutters B. Face milling cutters D. Form cutters

22.

The formula to find out the number of turn of the crank simple indexing is A. T=20/N C. T=N/20 B. T=40/N * D. T=N/40 In a standard dividing head the ratio between the worm wheel and the worm is A. 10:1 C. 20:1 D. 30:1 D. 40:1 *

23.

24.

There are two different movements of the crank in A. Simple indexing C.Compound indexing * B. Differential indexing D. Angular indexing

25.

In a vertical milling machine the spindle is situated to the A. Horizontal C. vertical * B. Angular D. None of the above

26.

Planer type built machine is built up for work of A. light duty C. heavy duty * B. medium duty D. None of the above

27.

In a straddle milling operation how many cutters are used to mill the work?

A. One B. Three or more

C. Two * D. Any one of the above

28.

All four compression coil spring support one load of 700 kg/mm. All four springs are arranged in parallel and rated same at 0.609 kg/mm. Compute the deflection in mm. A. 64 C. 178 B. 147 D. 287 *

29.

A body weighing 1000 lb falls 6 inches and strikes a 2000 lb per in spring. The deformation of the spring is: A. 1 in C. 3 in * B. 2 in D. 6 in

30.

A 60 inch diameter steel pipe, 3/8 inch thick, carries water under a pressure head of 550 ft. Determine the hoop stress in the steel. A. 34,320 psi C. 19,066 psi * B. 25,780 psi D. 15,920 psi

31.

The maximum moment induced in a simply supported beam of 20 ft span, by a 2000 pound load at midspan is A. 125,000 ft – lb C. 30,000 ft – lb B. 15,000 ft – lb D. 10,000 ft – lb *

32.

Determine the length of belt needed for a two flat belt pulleys having a diameter of 70 cm and 30 cm. The center distance is 400 cm and pulleys rotate in same direction. Assume power transmitted is 10 hp at 200 rpm. A. 958 cm * C. 589 cm B. 859 cm D. 895 cm

33.

A round steel bar 12 inches long is to withstand a dead load of 40,000 lb in compression. The rod must not shorten more than 0.004 inch and have a factor safety of at least 10. Assume the ultimate strength of the material to be 110,000 psi and modulus of elasticity to be 15,500,000 psi. Determine the diameter of the rod. A. 2.14 in. C. 4.14 in. B. 3.14 in * D. 5.14 in.

34.

How long will it take to saw a rectangular piece of steel plate size ½ “ x 4’ x 8’ the length of cut is 4 ft. The power hacksaw makes 120 rpm and the feed per stroke is 0.008 in.? A. 48 min. C. 50 hr B. 0.83 hr * D. 52 min. For gear cutting which cutter is used? A. End mill cutter C. Plain milling cutter B. Form relieve cutter * D. All of the above

35.

36.

In a slotter, the table gets ___ different feeds A. One C. Two B. Three * D. None of the above

37.

If a clearance of a cutting edge is 15 deg, the lip (wedge) angle in 75 deg, the rake angle will be A. 80 deg C. 70 deg B. 10 deg * D. None of the above

38.

The approximate hardness of HSS end mill cutter is A. 45 HRC C. 52 HRC B. 62 HRC * D. 72 HRC

39.

When the feed motion takes place in a slotting machine A. during the cutting motion. B. after each forward stroke. C. at the end of return motion. D. after each double stroke. * Which of the following conditions may cause error during knurling? A. to much longitudinal feed. *

40.

B. C. D.

clamped length of tool too short. surface speed too low. unnecessary support with tail stock center.

41.

Mark the milling method during which the formation of the chatter marks is very likely A. during down cut milling with a straight tooth cutter. B. during up cut milling with a straight tooth cutter. * C. during face milling with a straight tooth cutter. D. while using spiral tooth cutter.

42.

Mark the cutter which works simultaneously with up cut and down cut process A. Side milling cutter. B. Semi-circular milling cutter. C. Shell end mill. * D. Plain milling cutter.

43.

A polygon with 9 flats is to be milled using the indexing head. The indexing head transmission ratio is 40:1.Determine the number of crank rotation and mark the correct answer A. 9 full rotation. B. 5 full rotation, 2 holes on the 36 hole circle. C. 4 full rotation, 12 holes on the 27 hole circle. * D. 2 full rotation, 16 hole on the 47hole circle.

44.

Where the relieved cutters are reground? A. on the circumstances B. relieved cutters are not reground C. on the flank * D. on the side faces

45.

What happens if the job is loosely cylindrical grindings? A. the job will be out of round. * B. the job will be oversize. C. the job will be thrown out. D. the job will not rotate.

46.

Internal and external taper on cylindrical jobs are ground in A. plain cylindrical grinding machine. B. universal cylindrical grinding machine. * C. internal grinding machine. D. centreless grinding machine.

47.

Which of the following is used to clean the gauge blocks before and after use? A. Brush B. Cotton waste C. Chamois leather or lenen cloth * D. None of the above

48.

The grade of grinding wheel depends upon A. Grain size C. Structure B. Kind of abrasive D. Hardness of bond *

49.

Which kind of bond is commonly used? A. Vitrified * C. Rubber B. Shellac D. None of the above

50.

The symbol conventionally used for resinoid bond is A. ‘V’ C. ‘R’ B. ‘B’ * D. ‘E’

51.

A grinding wheel is marked as 51A 46L 5V 23, out of these 5 means A. Kind of abrasive C. Kind of bond B. Structure * D. Grain size

52.

Balancing of grinding wheel is done to

fitted

between

centers

in

A. B. C. D. 53. 54.

make the outside diameter concentric with the bore. make the sides of wheel parallel. equalize the weight in every portion of the wheel. * None of the above.

Taps are resharpened by grindings A. Flutes * C. Threads B. Diameter D. Relief The purpose of______is to prevent gears from jamming together making contact on both sides of their teeth simultaneously A. tooth fillet C. backlash * B. stress relieving D. all of these

and

55.

Choose the economical type of material for gears that give/sustain good operating quality/life for intended operation A. plane carbon steel C. all of these B. high alloy steel D. heat treated carbon steel *

56.

Allowance added in the contraction of metal A. tapering allowance B. shrinkage allowance *

casting

pattern

to

compensate

for

the

C. finish allowance D. draft pattern

57.

Ratio of the angle of action to the pitch angle A. contact ratio * C. ratio of gearing B. approach ratio D. module

58.

The principle materials used in the production of metal working tools: A. high carbon steel * B. titanium, phosphorous C. tungsten, silicon, hadfield Mn D. vanadium, chromium, molybdenum

59.

Also called eccentrically loaded bearing is ________. A. full bearings C. partial bearing B. offset bearing * D. fitted bearings

60.

In the selection of wire rope, regular lay means wires and strands are arranged in the following manner: A. twisted in the same direction B. twisted in opposite direction* C. twisted in any direction D. twisted in along direction

61.

In involute teeth, the pressure angle is often defined as the angle between the line of action and the line of tangent to the pitch circle. It is also termed asA. helix angle C. Angle of obliquity * B. angle of recess D. Arc of action

62.

Height of tooth above pitch circle or the radial distance between pitch circle and top land of the tooth. A. top root C. land B. addendum * D. hunting tooth

63.

The function of clutch in the machine tool is? A. lowering of drive speed B. to disconnect or connect at will the drive * C. alignment of drive shaft D. to insure that two shaft line up at high speed

64.

The rule of thumb in ratio/clearance should be. A. 0.0090 B. 0.0042

65.

journal

bearing

design;

the

clearance

C. 0.0010 * D. 0.00120

Cold rolled shafting is not available in diameter larger than__________ A. 6 inches C. 6 ½ inches B. 5 inches * D. 5 ½ inches

66.

The cast iron flywheels are commonly designed with a factor of safety of______ A. 14 to 15 C. 8 to 9 B. 10 to 13 * D. 6 to 12

67.

A pair of equal and opposite (not collinear) forces that tend cause a rotation of a body A. couple * C. equilibrium B. centroids D. vector

68.

The ratio of the pitch diameter in inches to the number of teeth A. pitch circle C. module B. English module * D. pitch diameter

69.

When high strength and durability are a requirements for choosing gear materials it is preferable to use_________material A. hardened bronze C. phenolic laminated B. steel * D. white iron

70.

The distance between similar, equally-spaced tooth surfaces in a given direction and along a given line. A. pitch circle C. pitch * B. pitch plane D. pitch diameter

71.

The use of hardened steel for the mating metal gear appears to give the best results and longer operational life. The usual hardness is in the range ofA. over 600 BHN * C. below 350 BHN B. 300 to 400 BHN D. over 400 BHN

72.

Continuous stretching under load even if the stress is less than the yield point A. plasticity C. creep * B. elasticity D. ductility

73.

The most known lubricants being utilized in whatever category of load and speed are oil, air, grease and dry lubricants like A. bronze C. silicon B. lead D. graphite *

74.

A coupling that allows axial flexibility/movement in the operation. Made of alternate bolting of steel, leather, fabric and/or plastic material into the two flanges A. Flexible disk coupling * B. flexing Oldham coupling C. Flexible toroidal spring coupling D. Elastic-material bonded coupling

75.

It consists of two cranks, a stationary piece called the centers and the connecting rod is a A. five-bar linkage C. three-crank linkage B. four-crank braces D. four-bar linkage *

76.

Find the torsional moment in N-m developed when the shaft delivers 40.2 hp at 260 rpm. A. 901 x 10 to the 3rd power C.1102 x 10 to the 2nd power B. 901 x 10 to the 2nd power D.1102 x 10 to the 3rd power *

77.

Compute how many ¼ inch diameter set at a shaft speed of 900 rpm. The shaft A. 2 C. B. 3 D.

78.

A pair of gear and pinion having a ratio of 4 with the gear having 100 teeth and the pinion with 25 teeth. Find the circular pitch, if the center distance is 15 and the pitch is at 6. A. 0.94 C. 0.610 B. 0.754 * D. 0.552

line

of

screws required to transmit 3 HP diameter is 1 ¼ in 4 * 2.5

79.

A gear of 80 teeth and a pinion of 20 teeth has a gear and pinion ratio of 4. Find the center distance , in inches, if the circular pitch is 0.885. A. 14.1 * C. 16.1 B. 15.1 D. 17.1

80.

The section modulus of a circle of radius 5 cm is equal to: A. 58.2 cm3 C. 98.2 cm3 * 3 B. 78.2 cm D. 108.2 cm3

81.

A hollow shaft with outside diameter of 14 cm and wall thickness of 0.08 cm transmits 200 kW at 400 rpm. What must be the angular deflection of the shaft if the length is 5 meters? Take G = 12,000,000 psi. A. 0.019 deg C. 1.94 deg B. 1.14 deg * D. 2.44 deg

82.

Compute the safe wall thickness of a 90 cm diameter steel tank. The tank is subjected to 7 MPa pressure and the steel material has yield stress of 220 MPa. Use a factor of safety of 3. A. 4.3 cm * C. 3.2 cm B. 3.8 cm D. 2.5 cm

83.

A bolt has a tensile load of 300 lbs. The bolt is made of SAE 1040 material with Sy = 55 ksi, what is the stress area of the bolt? A. 0.1023 in2 * C. 0.327 in2 2 B. 0.1230 in D. 0.5190 in2

84.

With an electric arc welding rate rate of 18 in/min, how long will it take to weld a ½ in. thick plate by 3 ft long seam? A. 3 min. C. 1.5 min. B. 2 min. * D. 4 min.

85.

Determine the power transmitted, in kW, by a main power transmitting steel shaft with 2 3/8 inches in diameter using SAE 1060 material mounting a 12 inches pulley at a speed of 170 rpm. A. 21.3 * C. 28.5 B. 25.8 D. 0.75

86.

Determine the polar section modulus, Zp (in3) of a shaft delivering 5 hp at 150 rpm. The diameter of the shaft is 1 inch and allowable stress of 6000 psi. A. 0.175 C. 0.489 B. 0.196 * D. 0.895

87.

Compute the deflection of a 20 coils helical spring having a load of 120 kgs. The modulus of elasticity in shear of spring is 98 GPa, outside diameter of 10 cm and wire diameter of 10 mm. The spring is squared and ground ends. A. 162.1 mm C. 134.1 mm B. 154.4 mm D. 126.1 mm *

88.

The torsional deflection of steel shaft is 0.6 deg per meter length. The shear stress is 60 MPa. Compute the diameter of the shaft in mm. Steel modulus of elasticity is 79 GPa. A. 90 mm C. 130 mm B. 105 mm D. 145 mm *

89.

What is the size of an air cylinder operating at 10 bar with a required force of 7854 N? Use a load ratio of 90%. Load ratio means the ratio of required force and theoretical force. A. 100 mm C. 150 mm B. 105 mm * D. 300 mm

90.

A steel rod 30 ft long used in a control mechanism must transmit a tensile force of 980 lb without stretching more than 1/8 in. nor

exceeding an allowable stress of 20,000 psi. What must the diameter of the rod be? (E = 30 x 106 psi ) A. 1/4 in C. 1/2 in B. 3/8 in * D. 3/4 in 91.

A steel bar initially free of stress, is held between rigid supports. Determine the stress in the bar if the temperature drops 130 deg F. (k = 6.5 x 10-6 per deg F) A. 11,400 psi C. 20,600 psi B. 15,600 psi D. 25,400 psi *

92.

When working on bearings and checking for high spots, it is customary to apply: A. white lead C. dykem blue B. red lead D. Prussian blue *

93.

If you wanted to check the face of a pump slide valve or other flatfaced valve, you could check for trueness on a: A. flat board C. piece of glass B. surface plate * D. bearing plate

94.

Before splicing electric wires, they should be: A. tinned C. soldered B. cleaned and tinned * D. insulated

95.

Which of the following is not a standard thread form? A. Square C. Double flute * B. American National D. 60 deg. sharp V

96.

Hand taps are provided in sets of three called: A. taper, plug and end C. taper, plug and bottom * B. short, taper and bottom D. short, medium and long

97.

When preparing to tap a hole, the size of the drill will be A. equal to the size of the tap B. larger than the size of the tap B. smaller than the size of the tap * D. none of the above

98.

99.

When preparing to tap a hole for a pipe fitting the size of the drill will be : A. larger than the tap size * B. smaller than the tap size C. equal to the size of the tap D. none of the above Which of the following does not have to be lubricated when drilling? A. steel C. monel B. brass * D. tool steel

100. The tool to use when cutting metal is called a: A. vise B. jaw holder

a hole in the side

*** END ***

of a round piece of

C. “V” block * D. chuck

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