• Author / Uploaded
• joe1256

Citation preview

Machine Design & Shop Practice

Refresh Trivia # 1

JCSF ENGINEERING REVIEW CENTER 2nd Floor Santos-Causing Building, National Highway Halang, City of Calamba, Laguna MACHINE DESIGN AND SHOP PRACTICE (Refreshers Trivia # 1) Prepared by: Jose R. Francisco, PME September 2012 INSTRUCTION: Select the correct answer for each of the following questions. Mark only one answer for each item by shading the box corresponding to the letter of your choice on the answer sheet provided. STRICTLY NO ERASURES ALLOWED. Use pencil No. 1 only 1.

o

If the angular deformation of a solid shaft should not to exceed 1 in a length of 1.8 m and the allowable shearing stress is 83 MMa, what is the 6 diameter of the shaft? Assume that the shaft material has G = 77 x 10 kPa. a) 222.34 mm b) 234.22 mm c) 23.42 cm d) 24.22 cm

⎛ πD3ss ⎞ ⎟L 32⎜ ⎜ 16 ⎟ TL 32T L ⎝ ⎠ = 2 ss L Solution: θ = = = JG πD 4G DG π D 4G 2.

E=

(

D=3

)

)

Where,

d) 3.28 inches

53.5 P 53.5(200 ) =3 = 2.28 inches N 900

For Main Power Transmitting Shaft:

For Small, Short Shaft:

P=

D3 N 80

P=

For Line Shaft Carrying Pulleys:

P=

D3N 53.5

D3N 38

P = transmitted power, Hp

N = shaft rpm

D = shaft diameter, in inches

A round steel shaft rotates at 200 rpm and is subjected to a torque of 275 N-m and a bending moment of 415 N-m. Determine the equivalent twisting moment. a) 597.84 N-m b) 456.42 N-m c) 546.43 N-m d) 497.85 N-m Solution:

ME =

M2 + T2 =

(415)2 + (275)2

= 497.85 N ⋅ m 2

A vertical steel cylinder water tank is 30 m in diameter and 45 m high. The allowable stress of the steel plate is 1224 kg/cm . Without reinforcing angle bars and rods, what is the thickness of the steel plate? a) 55.15 mm b) 51.55 mm c) 65.15 mm d) 61.55 mm Solution:

Where, 6.

(

F Stress 3163.27 kg / cm 2 (2.205 lb / kg )(2.54 cm / in )2 = A = = 42 857142.86 psi = 43 x 106 psi Strain δ 0.00105 L

A line shaft is to transmit 200 Hp at 900 rpm. Find the diameter of the shaft. a) 2.18 inches b) 2.28 inches c) 3.18 inches

Note:

5.

2(83 000)(1.8) = 222.34 mm π ⎞ 6 1 ⎜⎜ 77 x 10 ⎟⎟ ⎝ 180o ⎠ o⎛

2

Solution:

4.

2 ss L = θG

What modulus of elasticity in tension is required to obtain a unit deformation of 0.00105 from a load producing a unit tensile stress of 3163.27 kg/cm ? 6 6 6 6 b) 43 x 10 psi c) 45 x 10 psi d) 46 x 10 psi a) 40 x 10 psi Solution:

3.

D=

t=

(

)

pD 441 297 N / m 2 (30 m ) = = 0.05515 m = 55.15 mm 2 s t E j 2 1224 kg / cm 2 (9.8066 N / kg )(100 cm / m )2

(

)

p = maximum pressure inside the tank, Pa

(

)(

)

p = ρ g H = 1000 kg / m 3 9.8066 m / s 2 (45 m ) = 441 297 Pa

st = hoop stress of the tank, Pa The root diameter of a double square thread is 0.55 inch. The screw has a pitch of 0.2 inch. Find the outside diameter and the number of threads per inch. a) 0.75 inch and 5 threads/inch b) 0.50 inch and 5 threads/inch c) 0.75 inch and 4 threads/inch d) 0.50 inch and 4 threads/inch

1 Number of Threads per inch 1 1 Number of threads per inch = = =5 Where, p = the pitch p 0.2

Solution: For the number of threads per inch,

For the major diameter,

Where,

p=

⎛p⎞ D o = D i + 2h = D i + 2⎜ ⎟ = D i + p = 0.55 + 0.2 = 0.75 inch ⎝2⎠

h = height or depth of thread =

p 2

1

→ for square thread

Machine Design & Shop Practice 7.

Refresh Trivia # 1

A flat belt is 6 inches wide and 1/3 inch thick and transmits 15 Hp. The center distance is 8 ft. The driving pulley is 6 inches in diameter and rotates at 2 3 000 rpm such that the loose side of the belt is on top. The driven pulley is 18 inches in diameter. The belt material is 0.035 lb/in and the coefficient of friction is 0.30. Determine the belt net tension. a) 175.5 lb b) 157.5 lb c) 155.7 lb d) 165.7 lb Solution: F = F1 − F2 =

2 T 2 ⎛ 63 000 Hp ⎞ ⎛ 2 ⎞ ⎡ 63 000(15) ⎤ = ⎜ ⎟ = ⎜ ⎟⎢ ⎥ = 157.5 lb D D⎝ n ⎠ ⎝ 6 ⎠ ⎣ 2 000 ⎦

33 000 Hp 33 000(15) ⎛ 6⎞ = = 157.56 lb ⎟(2 000) = 3141.59 fpm F = F1 − F2 = 12 Vm 3141.59 ⎝ ⎠

Other Solution: Vm = π D n = π⎜ 8.

A right-handed single-thread hardened-steel worm has a catalog rating of 2.25 kW at 650 rpm when meshed with a 48-tooth cast-steel gear. The axial o pitch of the worm is 25 mm, normal pressure angle is 14.5 , and the pitch diameter of the worm is 100 mm. The coefficient of friction is 0.085. Determine the shafts center distance. a) 241 mm b) 142 mm c) 412 mm d) 124 mm Solution:

Speed Ratio, SR = Tanλ =

Tg D g cos λ Dg ωw n w = = = = ωg ng Tw D w sin λ D w tan λ

p L 25 = = = 0.07958 πD w πD w π(100 )

→ λ = 4.55 o

⎛ Tg ⎞ ⎛T ⎞ ⎞ ⎛T ⎛ ⎟ D tan λ = ⎜ g ⎟D w ⎜ p ⎟ = ⎜ g ⎜ πD ⎟ ⎜ T ⎜T ⎟ w ⎜T ⎟ w ⎠ ⎝ w ⎝ ⎝ w⎠ ⎝ w ⎠ D w + D g 100 + 381.97 Center Distance, C = = = 241 mm 2 2

Pitch diameter of the gear, D g = ⎜

9.

⎞⎛ p ⎞ ⎛ 48 ⎞⎛ 25 ⎞ ⎟⎜ ⎟ = ⎜ ⎟⎜ ⎟ = 381.97 mm ⎟⎝ π ⎠ ⎝ 1 ⎠⎝ π ⎠ ⎠

o

A 20 straight-tooth bevel pinion having 14 teeth and a diametral pitch of 6 teeth/inch drives a 42-tooth gear. The two shafts are at right angles and in the same plane. Find the pitch angle of the pinion. o o o o b) 20 c) 14.5 d) 20.5 a) 18.4 Solution: γ = tan

⎛ Tp ⎜ Tg ⎝

−1 ⎜

⎞ ⎟ = tan −1 ⎛⎜ 14 ⎞⎟ = 18.4 o ⎟ ⎝ 42 ⎠ ⎠

10. A double-thread worm has a pitch diameter of 3 inches. The wheel has 20 teeth and a pitch diameter of 5 inches. Find the gear helix angle. o o o o b) 9.46 c) 6.49 d) 6.94 a) 4.69 Solution:

⎡⎛ T λ = tan −1 ⎢⎜⎜ w ⎢⎣⎝ Tg

⎞⎛ D g ⎟⎟⎜ ⎜ ⎠⎝ D w

⎞⎤ ⎡ ⎤ ⎟⎥ = tan −1 ⎢ 2 ⎛⎜ 5 ⎞⎟⎥ = 9.46 o ⎟⎥ 20 3 ⎝ ⎠ ⎣ ⎦ ⎠⎦ o

11. A 36-tooth pinion turning at 300 rpm drives 120-tooth gear of 14.5 involute full depth pressure angle. Determine the rpm of the driven gear. a) 60 rpm b) 45 rpm c) 75 rpm d) 90 rpm

⎛ Tp ⎞ ⎟ = (300)⎛⎜ 36 ⎞⎟ = 90 rpm ⎟ T ⎝ 120 ⎠ ⎝ g⎠

Solution: n g = n p ⎜ ⎜

12. If two parallel shafts are connected by cylinders in pure rolling contact and turning in the same direction, and having a speed ratio of 2.75, what is the Center distance of the two shafts assuming that the diameter of the smaller cylinder is 22 cm? a) 18.25 cm b) 19.25 cm c) 20.25 cm d) 17.25 cm Solution:

Diameter of the bigger cylinder, D 2 = SR (D 1 ) = 2.75(22 ) = 60.5 cm Center distance, C =

D 2 − D1 60.5 − 22 = = 19.25 cm 2 2

13. Two extension coil springs are hooked in series that support a single weight of 100 kg. The first spring is rated at 4 kN/m and the other spring is rated at 6 kN/m. Determine the total deflection of the springs. a) 408.6 mm b) 486.0 mm c) 480.6 mm d) 460.8 mm Solution:

δ t = δ1 + δ2 =

⎛ k + k2 ⎞ ⎡4 + 6⎤ F F ⎟⎟ = (100 kg )(9.8066 N / kg )⎢ + = F⎜⎜ 1 ⎥ = 408.6 mm k1 k 2 ⎣ 4(6) ⎦ ⎝ k1k 2 ⎠

14. A double thread ACME screw driven by a motor at 400 rpm raises the attached load of 900 kg at a speed of 10 m/min. The screw has a pitch diameter of 36 mm; the coefficient of friction on threads is 0.15. The friction torque on the thrust bearing of the motor is taken as 20 % of the total input. Determine the lead angle. o o o o b) 14.265 c) 15.462 d) 16.452 a) 12.465

V 10 = = 0.025 m = 25 mm n 400 −1 ⎛ L ⎞ −1 ⎛ 25 ⎞ o For the lead angle, λ = tan ⎜ ⎜ πD ⎟⎟ = tan ⎜⎝ 36π ⎟⎠ = 12.465 m ⎠ ⎝

Solution: For the lead,

L=

15. A cylinder having an internal diameter if 508 mm and external diameter if 914.4 mm is subjected to an internal pressure of 69 MPa and an external pressure of 14 MPa. Determine the hoop stress at the inner surface of the cylinder. a) 90.11 MPa b) 91.10 MPa c) 911.0 MPa d) 19.10 Mpa

2

Machine Design & Shop Practice

Solution:

s ti =

(

Refresh Trivia # 1

⎡

)

p i ro2 + ri2 − 2p o ro2 ro2 − ri2

(69 MPa )⎢⎛⎜ 914.4 ⎣⎢⎝

=

2

2 2 2 ⎛ 914.4 ⎞ ⎞ ⎤ ⎞ ⎛ 508 mm ⎟ + ⎜ mm ⎟ ⎥ − 2(14 MPa )⎜ mm ⎟ ⎝ 2 ⎠ ⎠ ⎝ 2 ⎠ ⎥⎦ 2

⎛ 914.4 ⎞ ⎛ 508 ⎞ mm ⎟ − ⎜ mm ⎟ ⎜ ⎝ 2 ⎠ ⎝ 2 ⎠

sti = 90.11 Mpa sti = maximum tangential or hoop stress at the inside ro = outside radius, mm pi = internal pressure, Mpa Note: For the maximum tangential or hoop stress at the outside,

2

ri = inside radius, mm po = external pressure, Mpa

Where,

16. A flat belt is 6 inches wide and 1/3 inch thick and transmits 15 Hp. The center distance is 8 ft. The driving pulley is 6 inches in diameter and rotates at 2 3 000 rpm such that the loose side of the belt is on top. The driven pulley is 18 inches in diameter. The belt material is 0.035 lb/in and the coefficient of friction is 0.30. Determine the belt net tension. a) 175.5 lb b) 157.5 lb c) 155.7 lb d) 165.7 lb Solution:

F = F1 − F2 =

2 T 2 ⎛ 63 000 Hp ⎞ ⎛ 2 ⎞ ⎡ 63 000(15) ⎤ = ⎜ ⎟ = ⎜ ⎟⎢ ⎥ = 157.5 lb D D⎝ n ⎠ ⎝ 6 ⎠ ⎣ 2 000 ⎦

17. What is the polar section modulus of a solid shaft with a diameter of 101.6 mm? 3 4 3 b) 209.5 cm c) 205.9 cm a) 209.5 cm

J 2J π 3 π = = D = (10.16 )3 = 205.9 cm 3 c D 16 16

Zj =

Solution:

4

d) 205.9 cm

18. The transmitted torque of a hollow shaft is 3400 N-m at a shearing stress of 55 MPa. If the outside diameter is 1.25 times that of the inside diameter, what is the inside diameter, in mm? a) 64.87 b) 46.87 c) 84.67 d) 74.64

ss =

Solution:

16T

(

π D 1− β 3

D=3

4

16 T

(

π ss 1 − β

4

)

where, β =

)

=3

Di 1 = = 0.8 D o 1.25

16(3.4 )

[

π(55 000)1 − (0.8)

4

]

= 81.092 mm

Di =

Do 81.092 = = 64.87 mm 1.25 1.25

19. What is the stress area of a 1-inch diameter bolt that has a TPI (Threads per inch) of 8? 2 2 2 b) 0.626 in c) 0.443 in a) 0.565 in Solution: A = π [D − 0.9743p ]2 : → p = 1 : s

TPI

4

2

d) 0.606 in

→ A s = 0.606 in 2

20. Determine the Poisson’s ratio of a material whose modulus of elasticity is 200 GPa and whose modulus of rigidity is 80 GPa. a) 0.33 b) 0.25 c) 0.38 d) 0.22 Solution: G

=

E 2(1 + ν)

E = 200GPa,

∴ν = 0.25

G = 80GPa:

21. A steel has a BHN = 300. What is its approximate ultimate strength in ksi? a) 300 ksi b) 150 ksi c) 75 ksi

d) 200 ksi

Solution: Su ≈ 0.5(BHN), ksi 22. What is the pitch of an American Standard Screw Threads with designation 12-28 UNF? a) 0.083 inch b) 0.0357 inch c) 0.5 inch

d) 0.75 inch

1 1 1 = = 0.0357 inch Solution: p = = n No. of threads per inch 28 23. A thrust washer has an inside diameter of 12.7 mm and an outside diameter of 76.2 mm. For an allowable bearing pressure of 90 psi, determine the axial load that the washer can sustain. a) 618.5 lb b) 537.2 lb c) 702.2 lb d) 871.2 lb

(

)

2 2 π ⎡⎛ 76.2 ⎞ ⎛π⎞ 2 ⎛ 12.7 ⎞ ⎤ ⎟ D o − D i2 = (90 ) ⎢⎜ ⎟ −⎜ ⎟ ⎥ = 618.5 lb 4 ⎢⎝ 25.4 ⎠ ⎝4⎠ ⎝ 25.4 ⎠ ⎥⎦ ⎣

Solution: F = pA = p⎜

24. What is the number of threads per mm and the tensile stress area of a standard Metric screw Thread designated by M10 x 1.5? 2 2 2 2 c) 1.5 and 57.99mm d) 1.75 and 57.99 mm a) 0.555 and 57.99 mm b) 0.667 and 57.99 mm Solution: n =

1 1 = = 0.667 threads per mm p 1.5

[

]2 = 57.99 mm 2

For Standard Metric Screw Threads, A t = 0.7854(D − 0.9383p ) = 0.7854 10 − 0.9383(2.5) 2

2

Where At = tensile stress Area, mm ; D = basic major diameter, mm; p = pitch, mm Note: o M stands for standard metric screw threads; 10 stands for the basic major diameter, which is 10 mm; 1.5 stands for pitch that is 1.5 mm. 2

25. An air cylinder has a bore of 25 mm and is operated with shop air at a pressure of 6.327 kg/cm . Find the push force exerted by the piston rod, in N.

3

Machine Design & Shop Practice

Refresh Trivia # 1

a) 127.57

(

b) 70.42

)

c) 402.75

d) 304.57

⎛π⎞ 2 ⎛π⎞ 2 2 Solution: F = pA = p⎜ ⎟ D = 6.327 kg / cm (9.8066 N / kg )⎜ ⎟(2.5 cm ) = 304.57 N ⎝4⎠ ⎝4⎠ 26. A single plate clutch has an outside diameter of 250mm and a coefficient of friction of 0.3 between the surfaces. Using the uniform wear method, what is its maximum power transmitting capacity at 1000 rpm if the lining pressure is not to exceed 0.4 MPa? a) 38.1 kW b) 27.9 kW c) 29.7 kW d) 31.8 kW Solution:

⎡ (D + d) ⎤ T = Pf ⎢ ⎥ N fs : ⎣ 4 ⎦ To maximize T, take

d (D − d ) 2 D → thus, d = 3

→ P = πp max dT =0 dd

Then P = 9583N; → T = 283411N − mm :

→ d = 144.34mm

→ Power =

T(n ) = 29.7 kW 9.549 x10 6

27. Calculate the resultant bending load on a shaft that carries a 200mm-diameter, 20º full depth pinion. The pinion transmits 10 kW at 1750 rpm. a) 258.0 N b) 685.0 N c) 850.2 N d) 580.2 N

⎡ 10 ⎤ 2⎢ x 9.549 x106 ⎥ 2 T 1750 ⎦: Solution: Ft = = ⎣ D 200

→ Ft = 546.7 N

→ Fr = Ft tan φ = 198.6 N :

→ FR = Ft2 + Fr2 = 580.2 N o

28. A pulley 600 mm in diameter transmits 40 kW at 500 rpm. The arc of contact between the belt and pulley is 144 , the coefficient of friction between belt and pulley is 0.35 and the safe working stress of the belt is 2.1 MPa. Determine the belt tensions ratio, neglecting the effect of centrifugal force. a) 2.41 b) 2.14 c) 1.24 d) 4.12 ⎛ π ⎞ F1 0.35 (144 )⎜ ⎟ = e fθ = (e ) ⎝ 180 ⎠ = 2.41 F2

Solution:

29. A roller chain and sprocket is to drive vertical centrifugal discharge bucket elevator. The pitch of chain connecting sprockets is 1.75”. The driving sprocket is rotating at 120 rpm and has 11 teeth while the driven sprocket is rotating at 38 rpm. Determine the number of teeth of driven sprocket. a) 33 teeth b) 35 teeth c) 30 teeth d) 34 teeth Solution:

⎛n ⎞ ⎛ 120 ⎞ T2 = T1 ⎜⎜ 1 ⎟⎟ = (11)⎜ ⎟ = 34.74 ≈ 35 teeth ⎝ 38 ⎠ ⎝ n2 ⎠

30. A 20-tooth motor sprocket, running at 1200 rpm, drives a blower at a speed ratio of 4:1. Using the largest permissible chain size and the largest permissible center distance of 80 pitches, what length of chain in pitches is required to connect the sprockets? a) 200 pitches b) 212 pitches c) 216 pitches d) 220 pitches 2 3

⎡ 900 ⎤ Solution: p ⎥ = 0.825in. : largest RC no. is RC 60 max = ⎢ ⎣ n1 ⎦

(N − N t1 ) = 212.pitches N t1 + N t 2 + 2C p + t 2 2 40C p 2

Lc =

o

31. A 20 involute spur gear has a tooth whole depth of 16.95 mm, a tooth thickness of 13.2 mm, and a pitch of 3. Determine the circular pitch of the gear. a) 26.6 mm b) 16.6 mm c) 25.6 mm d) 24.6 mm Solution:

Pc =

π π = = 1.0472 inches = 26.6 mm Pd 3 th

32. Which of the following is the 4 most commonly used metal in the world? a) Zinc b) Steel c) Aluminum d) Copper 33. These springs are made from one or more flat strips of brass, bronze, steel or other materials loaded as cantilevers or simple beam. a) Torsion springs b) Leaf springs c) Garter springs d) Drawbar springs 34. This refers to the space between adjacent coils when the spring is compressed to its operating length. a) Coil clearance b) Pitch c) Lead d) Deflection 35. This material is the most popular alloy spring steel for conditions involving higher stresses than can be used with the high-carbon steels and for use where fatigue resistance and long endurance are needed; this is also good for shock and impact loads. a) Chrome silicon b) Chrome vanadium c) hard-drawn wire d) Oil-tempered wire 36. For an American Standard Screw Threads, what does 6-32 UNC designate? a) Size 6, 32 threads per inch, coarse thread b) 6 inches basic diameter, 32 threads per inch, coarse thread c) Size 6, 32 threads per inch, fine thread d) 32 inches basic diameter, 6 threads per inch, coarse thread • Note: 6 stands for the designated size, 32 stands for the number of threads per inch, UNC stands for Coarse threads 37. How do you call the process of producing the residual compressive stress of machine parts, which is performed by directing the a high velocity stream of hardened balls or pellets at the surface to be treated. a) Nitriding b) Shot blasting c) Peening d) Tempering 38. It is a process that produces residual compressive stress on the machine part, which uses a series of hammer blows on the surface. a) Nitriding b) Shot blasting c) Peening d) Tempering o 39. It is a surface-hardening process for alloy steels in which the material is heated to 950 F in a nitrogen atmosphere, typically ammonia gas, followed by slow cooling. a) Quenching b) Nitriding c) Shot blasting d) Peening 40. Which of the following gases is typically used in nitriding process of surface hardening? a) Nitrogen gas b) Carbon dioxide c) Ammonia gas d) Hydrogen gas 41. Which of the following is the benefit in using nitriding as a surface-hardening process for alloy steels? a) Improvement of endurance strength, 50 % or more b) Improvement of endurance strength, less than 50 %

4

Machine Design & Shop Practice

Refresh Trivia # 1

c) Improvement of endurance strength, more than 50 % d) 80 % improvement on the endurance strength 42. In estimating the actual endurance strength of steel parts, one of the factors to be considered is the material factor, which of the following is the recommended material factor for cast steel? a) 0.70 b) 0.80 c) 0.75 d) 1.0 43. How do you call the level of stress that the part will be permitted to see under operating conditions? a) Yield stress b) Endurance stress c) Design stress d) Ultimate stress 44. Which of the following column formulas is applicable to cast iron columns? a) Euler’s formula b) J.B.Johnson’s formula d) Secant formula d) Straight line formula o

Ans. D. Straight line formula. Cast iron columns are usually designed on the basis of

P ⎡L ⎤ = 9000 − 40 ⎢ e ⎥ A ⎣k ⎦ o

→ a Straight line formula

Where the slenderness ratio Le/k should not exceed 70.

45. Which of the following ferrous metals has the lowest carbon content? a) Carbon steel b) Wrought iron c) Cast iron d) SAE 4140 o Wrought iron usually contains less than 0.04% C; steel usually has less than 2.5% C; cast iron has more than 1.7% C; SAE 4140 has approximately 0.4% C. 46. If stiffness is the main criterion in selecting a material, which of the following is the most economical choice? a) SAE 3130 b) SAE 1020 c) SAE 6150 d) AISI 301, ¼ hard stainless steel o Ans. B. SAE 1020- plain carbon steel. All of the above materials are steel with practically equal modulus of elasticity. The three other materials are alloy steels that are relatively more expensive. 47. Which of the following materials can easily be machined? a) AISI C1020 b) AISI C1112 c) AISI C1030 d) AISI C1010 o Ans. b. C1112. This is a free-cutting steel with a higher sulfur content for ease in machining 48. This is a combination of mechanisms and other components that transforms, transmits, or uses energy, load, or motion for a specific purpose. How do yopu call this? a) Mechanism b) Engine c) Machine d) Linkage 49. It is the capacity of a material to absorb energy when it is deformed elastically and then, upon unloading, to increase this energy. What is this capacity of a material? a) Resilience b) Toughness c) Rigidity d) Ductility 50. What is the ability of the material to absorb energy up to fracture? a) Toughness b) Rigidity c) Resilience d) Stiffness 51. It is a failure prediction theory, which states that a part subjected to any combination of loads will fail (by yielding or fracturing) whenever the maximum shear stress exceeds a critical value. How do you call this failure prediction theory? a) Distortion-energy theory b) Maximum-shear-stress theory c) Internal friction theory d) Modified Mohr theory 52. What is the difference between the maximum and minimum size limits of a part? a) Allowance b) Tolerance c) Deviation d) Basic size 53. A lubrication condition where non-conformal surfaces are completely separated by lubricant film and no asperities are in contact. a) Elastohydrodynamic lubrication b) Boundary lubrication c) Hydrodynamic lubrication d) Hydrostatic lubrication 54. In a lathe machine, how do you call the diameter of the largest workpiece that can be rotated in a chuck or between centers without hitting the bed? a) Chuck diameter b) Swing c) Distance between centers d) Spindle diameter 55. How do you call a statistical data used to identify the most likely failure modes? a) Finite element analysis b) Fault free analysis c) Failure analysis d) Random analysis 56. It is a type of coil spring where the helical coil is wrapped into a circle forming an annular ring. How do you call this spring? a) Volute spring b) Motor spring c) Hair spring d) Garter spring 57. Wood is an ______ material; that is, its mechanical properties are unique and independent in three mutually perpendicular directions—longitudinal, radial, and tangential. a) Isotopic b) Anisotropic c) Orthotropic d) Any of these 58. The principal raw materials used in steelmaking are iron ore, coal, and __________. a) Coke b) Limestone c) Slag d) Flux 59. The steel part is heated to a temperature of 900–1150 degrees F in an atmosphere of ammonia gas and dissociated ammonia for an extended period of time that depends on the case depth desired. a) Nitriding b) Carburizing c) Case hardening d) Cyaniding 60. The primary application of high-speed steels is to tools used for the working of metals __________. c) that are too soft d) at slow cutting speeds a) that are too hard b) at high cutting speeds 61. In gearing, this is the ratio of the arc of action to the circular pitch. a) Speed ratio b) Arc ratio c) Contact ratio d) Gear ratio 62. Flywheel arms are usually of elliptical cross-section, the strength of the arms should equal _________the strength of the shaft in torsion. a) Three-fourths b) One-half c) Two-thirds d) One-fourth 63. This alloy (nickel, iron, chromium, cobalt is a non-magnetic, corrosion resistant material suitable for sub-zero temperatures and temperatures up to about 750 degrees F., provided that torsional stresses are kept below 75,000 pounds per square inch. It is precipitation-hardened to produce hardnesses of 48 to 50 Rockwell C and is used in watch and instrument springs. a) Elinvar b) Monel c) Inconel d) Dynavar Ans. Dynavar; source: Machinery’s handbook 64. To ensure an adequate factor of safety in the design of a shaft with standard keyway, the key width should be about: a) One half of the shaft diameter b) One fourth of the shaft diameter c) One eighth of the shaft diameter d) One third of the shaft diameter Note: One-fourth of shaft diameter, as a guide in key selection for both square and flat rectangular keys. 65. What is the property of matter that causes it to resist any change in its motion or state of rest? a) Momentum b) Kinetic Energy c) Inertia d) Section modulus 66. This is defined as the cutting time to reach a predetermined wear, called the tool wear criterion. a) Wear duration b) Cycle time c) Tool life d) Life cycle

5

Machine Design & Shop Practice

Refresh Trivia # 1

67. Which of the following G-codes refers to rapid traverse in CNC machining? a) G00 b) G01 c) G02 d) G03 68. An acronym in CNC machining which means access of the machine operator to insert machining instructions directly into the NC machine control system via push buttons, pressure pads, knobs, or other arrangements. a) FMS b) FMC c) CIM d) MDI Note: MDI = manual data input 69. The variable polarity plasma arc (VPPA) process was developed for welding metals that form an oxide skin, such as ___________. a) Steel b) Copper c) Cast iron d) Aluminum 70. Which of the following statements is NOT true? a) The terms “polishing” and “buffing” are sometimes applied to similar classes of work in different plants. b) Polishing is any operation performed with wheels having abrasive glued to the working surfaces c) Buffing is done with wheels having the abrasive applied loosely d) Polishing is not so harsh an operation as buffing, and it is commonly utilized to obtain very fine surfaces having a “grainless finish.” Note: Polishing is harsher than buffing. 71. If the steel is strongly deoxidized by the addition of deoxidizing elements, no gas is evolved, and the steel is technically called _______because it lies quietly in the molds. a) Quenched b) Annealed c) Killed d) Tempered 72. Stainless steels generally contain at least __ per cent chromium, with or without other elements. a) 18 b) 16 c) 12 d) 10 73. What grades of stainless steels are nonmagnetic in the annealed condition, although some may become slightly magnetic after cold working? a) Ferritic grades b) Austenitic grades c) Martensitic grades d) Any of these 74. These steels (SAE Steels 1006, 1008, 1010, 1015) are the lowest carbon steels of the plain carbon type, and are selected where ________ is the primary requisite of the user. a) Strength b) Cold formability c) Ductility d) Durability 75. What process is used to produce residual compressive stress on the crankshaft? a) Hardening b) Shot blasting c) Peening d) Nitriding 76. Steel is heated to a temperature above the critical range, after which it is cooled in still air to produce a generally fine pearlite structure. The purpose is to promote uniformity of structure and properties after a hot-working operation such as forging or extrusion. What was the heat treatment involved? a) Annealing b) Normalizing c) Tempering d) Stress relieving 77. At certain speeds called the critical speeds, a rotating shaft will become dynamically unstable and the resulting vibrations and deflections can result in damage not only to the shaft but to the machine of which it is a part. At what percentage of the critical speed should a shaft be safely operated? a) Plus or minus 20% b) Plus or minus 5 % c) Plus or minus 10 % d) Any of these 78. This is the most widely used of all spring materials for small springs operating at temperatures up to about 250 degrees F. It is tough, has a high tensile strength, and can withstand high stresses under repeated loading. a) Music wire b) Hard drawn spring wire c) Oil tempered spring wire d) Stainless steel spring wire 79. It is an acronym in machining. This process uses an electrode to remove metal from a workpiece by generating electric sparks between conducting surfaces. a) MIG b) GMAW c) EDM d) CNC Ans. Electro-Discharge Machining (Source: Machinery’s Handbook) 80. In die casting accurate parts made of steel, what shrinkage allowance in inches per inch is recommended? a) 0.011 b) 0.022 c) 0.033 d) 0.044 Ans. 0.022. (Source: Machinery’s Handbook) 81. This are gears used to connect shafts that are non-intersecting and non-parallel. They are a cross between spriral bevel gears and worm gears. a) Helical gears b) Hypoid gears c) Planetary gears d) Bevel gears 82. This is a type of seal used where some form of relative motion occurs between rigid parts of an assembly. a) Gasket b) Distorted seal c) Vibratory seal d) Dynamic seal 83. It is a lubrication for roller chains wherein the lubricant is supplied by a circulating pump capable of supplying the chain drive with a continuous flow of oil inside the chain loop evenly across the chain width and directly at the slack strand. a) Oil stream lubrication b) Bath lubrication c) Drip lubrication d) Recirculated lubrication 84. In manufacturing, this is the operation of cutting out flat area to some desired shape and is usually the first step in a series of operation. d) Finishing a) Turning b) Facing c) Blanking 85. An M-code which generally refers to start spindle rotation in a clockwise direction. a) M03 b) M04 c) M05 d) M06 86. A final operation to improve the polish of a metal and to bring out the maximum luster a) Finishing b) Surface grinding c) Broaching d) Buffing 87. Machining operations with the proper application of a cutting fluid generally has the following attributes except: a) Higher cutting speeds b) Higher feed rates c) Lengthened tool life d) Higher cutting accuracy 88. A material of construction (only developed commercially in the late 1940’s concurrently with zirconium) offers the unique combination of wide ranging corrosion resistance, low density, and high strength. a) Tungsten b) Titanium c) Vanadium d) Molybdenum 89. Which of the following is the lightest of all structural metals? a) Aluminum b) Copper c) Magnesium d) Manganese 90. This process reduces internal stresses, caused by machining, cold working, or welding, by heating the steel to a temperature below the critical range and holding it there long enough to equalize the temperature throughout the piece. a) Annealing b) Normalizing c) Tempering d) Stress Relieving 91. A free-cutting steel has a higher ______ content than comparable carbon steels. a) Sulfur b) Cobalt c) Nickel d) Chromium 92. This property designates the steels resistance to the softening effect of elevated temperature. a) Hot hardness b) Machinability c) Toughness d) Elasticity 93. Use of hard solders, silver solders and smelter solders which have silver, copper, or nickel bases and have melting points above 800 degrees F is known as_______ a) Soldering b) Welding c) Brazing d) Any of these 94. In braking, the term backstop refers to a brake that is:

6

Machine Design & Shop Practice

Refresh Trivia # 1

a) Self locking in one direction b) Self energizing c) Self locking in both directions d) Any of these 95. How do you call a fixed crane consisting of a supported vertical member from which extends a horizontal swinging arm carrying a trolley hoist or other hoisting mechanism? a) Jib crane b) Gantry crane c) Overhead crane d) Tower crane 96. This iron is also known as a ductile cast iron. How do you call this iron? a) Malleable iron b) Nodular cast iron c) White cast iron d) Gray cast iron 97. It is the ability to deform plastically to compensate for irregularities in bearing assembly. How do you call this? a) Plasticity b) Conformability c) Embeddability d) Elasticity 98. A material of construction (only developed commercially in the late 1940’s concurrently with zirconium) offers the unique combination of wide ranging corrosion resistance, low density, and high strength. a) Titanium b) Tungsten c) Vanadium d) Molybdenum 99. Newton’s law of motion that describes that if a force acts to change the state of motion of the body, the body offers a resistance equal and directly opposite to the force. a) Second law b) Third law c) First law d) Universal gravitation 100. The most widely used material for machine elements because of its properties of high strength, high stiffness, durability, and relative ease of fabrication. a) Zinc b) Steel c) Aluminum d) Copper

1. 2.

3. 4.

5. 6.

7. 8.

Note: The following questions are for your reading and Familiarization What is this type of roller bearing in which the balls are assembled by the eccentric displacement of the inner ring? a) Shallow-groove ball bearing b) Self-aligning ball bearing c) Filling-slot ball bearing d) Deep-groove ball bearing Which if the following is not a type of ball bearing? a) Shallow-groove ball bearing b) Self-aligning ball bearing c) Filling-lot ball bearing d) Deep-groove ball bearing Which of the following ranges of belt speed suggests the most economical designs? a) 4000 to 4500 fpm b) 2000 to 3000 fpm c) 3000 to 4000 fpm d) 4000 to 5000 fpm What do you a wire rope in which the wires and strands are twisted in opposite directions? a) Long lay b) Lang lay c) Regular lay d) Performed What do you call a wire rope in which the wires and strands are twisted in same direction? a) Long lay b) Lang lay c) Performed What is the product of the length and diameter of a bearing? a) Projected area b) Shearing area c) Compressive area Which gauge is used to check internal threads? a) Plug gauge b) Ring gauge c) Thread plug gauge When outside diameter of a job is turned in relation to the internal hole, the job should be held: a) In three-jaw chuck b) On the lathe mandrel c) On face plate

d) Non-performed d) Cross-sectional area

d) Thread ring gauge d) Between centers

9.

Which of the following is the measure of modulus of elasticity? a) Accuracy b) Quality c) Stiffness d) Rigidity 10. How do you call the ratio of moment and stress? a) Strain b) Contraction c) Proportional constant d) Section Modulus 11. For a symmetrical cross-sectional beam, what is the value of flexural stress when the vertical shear stress is at maximum? a) Infinity b) Maximum c) Zero d) Minimum 12. In a pressure vessel, how do you call the ratio of minimum strength of joint to the strength of the solid joint? a) Efficiency b) Performance Factor c) Joint Efficiency d) Relative Strength 13. What is the usual factor of safety in a pressure vessel? a) 2 b) 4 c) 3 d) 5 14. In a lathe machine, how do you call the diameter of the largest workpiece that can be rotated in a chuck or between centers without hitting the bed? a) Chuck diameter b) Swing c) Distance between centers d) Spindle diameter 15. It is a kind of mandrel made of soft metals or hard wood that is used to prevent the workpiece to be meshed, especially soft metals for thin cylinders. How do you call this mandrel? a) Homemade mandrel b) Taper mandrel c) Threaded mandrel d) Gang mandrel 16. It is called as any internal stress that exists in a part at uniform temperature and not acted upon by an external load. What is this type of stress? a) Residual stress b) Superposed stress c) Form stress d) Control stress 17. How do you call a phenomenon when two touching surfaces have a high contact pressure and when these surfaces have minute relative motion? a) Pre-stressing b) Friction c) Carving d) Fretting 18. What is this part of headstock of a lathe machine used to transmit power from the spindle? a) Motor b) Back gear c) Headstock spindle d) Switch 19. When a hot part is cooled suddenly by quenching, there is momentarily a high temperature gradient that induces a stress gradient. Some metal parts under certain conditions crack as a result. What is this phenomenon? a) Thermal-shock failure b) Thermal fatigue c) Honing d) Quenching 20. Fatigue strength is increased by repeated loads just below the normal fatigue limit and followed by small step-by-step increases of the loading. What is this? a) Mixing b) Coaxing c) Axing d) Relieving 21. How do you call an axial distance that a screw advances in one turn or revolution? a) Lead b) Circular pitch c) Pitch d) Axial pitch

7

Machine Design & Shop Practice

Refresh Trivia # 1

22. What is a screw fastener with a nut on it? a) Bolt b) Rivet c) Fastener d) Square screw 23. It is a type of bolt distinguished by a short portion of shank underneath the head, being square or finned or ribbed. What is this bolt? a) Coupling bolt b) Machine bolt c) Stud bolt d) Carriage bolt 24. How do you call a large wood screw that is used to fasten machinery and equipment to a wooden base? a) Lag screw b) Wood screw c) Log screw d) Square screw 25. How do you call the ratio of mean diameter of coil and the coil diameter of a spring? a) Wahl number b) Diameter ratio c) Spring index d) Lead angle 26. It is a low cost spring material, suitable where service is not severe and dimensional precision is not needed. How do you call this spring material? a) Hard drawn wire b) helical spring wire c) Stainless steel d) helical tension spring wire 27. How do you call a spring material that is hard drawn (80 % reduction) but made up of high-grade steel? a) Music wire b) Oil tempered wire c) Song wire d) Chromium-silicon wire 28. It is a spring wire with good quality for impact loads and moderately high temperatures. What is this spring material? a) Hard drawn spring wire b) helical spring wire c) Chromium-silicon d) Helical tension wire 29. It is a type of coil spring where the helical coil is wrapped into a circle forming an annular ring. How do you call this spring? a) Volute spring b) Motor spring c) Hair spring d) Garter spring 30. It is a type of spring where thin flat strip wound up on itself as a plane spiral, usually anchored at the inside end. What do you call this spring? a) Volute spring b) Motor spring c) Hair spring d) Garter spring 31. What do you call a ratio of the length of the column and the radius of gyration of the cross-sectional area about the centroidal axis? a) Power factor b) Contact ratio d) Constant ratio d) Slenderness ratio 32. A screw that requires a positive torque to lower the load, or to loosen the screw if it has been turned tight against a resistance. How do you call this screw? a) Power screw b) Self screw c) Lock screw d) Self-locking screw 33. What is the other term used for Kennedy key? a) Tangential key b) Normal key c) Saddle key d) Rollpin key 34. Which of the following device used to measure the speed accurately? a) Dial gage b) Dial indicator c) Speedometer d) Tachometer 35. When the hole is smaller than the shaft, it will take pressure to put the parts together. The allowance is said to be negative and is termed as: a) Interference of metal b) Negative allowance c) Negative tolerance d) Negative fits 36. When two elastic bodies collide, which of the following laws can be used to solve for the resulting velocity? a) Avogadro’s law b) Conservation of momentum and conservation of energy c) Dalton’s law of partial pressure d) Conservation of energy 37. What is the ability of metal to be deformed considerably without rupture? a) Toughness b) Stiffness c) Plasticity d) Ductility 38. It is a science of motion that can be solved in terms of scalar or vector algebra. How do you cal this science? a) Kinematics b) Dynamics of machine c) Engineering mechanics d) Strength of materials 39. A system of forces in space is in equilibrium. If two equal and opposite collinear forces are added, which of the following if any is true? a) Forces are in opposite directions b) Equilibrium is destroyed c) Equilibrium is maintained d) An unbalanced of moment exist 40. It is a metal that assists lubrication or lubricant in itself. What is this metal? a) Lead b) Babbit c) Zinc d) Antimony 41. What do you call a mechanism that usually does the indexing in a machine tool? a) Indexing machine b) Dividing head c) Slotter c) Universal chuck 42. The machine element equalizes the energy exerted and the work done thus preventing excessive or sudden changes of speed. What is this machine element? a) Pulley b) Gear b) Flywheel d) Shaft 43. How do you call the product of the resultant of all forces acting on a body and the time that the resultant acts? a) Linear momentum b) Linear impulse c) Angular momentum c) Angular impulse 44. Which of the following is not a structure class of steel? a) High strength low alloy steel b) High chrome alloy steel c) Tool and die steel d) Low carbon steel 45. Poison ratio is defined as the ratio of which of the following? a) Lateral strain and longitudinal strain b) Shear strain and compressive strain c) Elastic limit and proportional limit d) Elastic limit and compressive strain 46. How do you call a property of material that relates the lateral strain to the longitudinal strain? a) Stress b) Poison’s ratio c) Modulus of resilience d) Strain 47. This is a maximum stress to which a material may be subjected before failure occurs. What do you call this maximum stress? a) Ultimate stress b) Endurance limit c) Yield stress c) Ultimate strength 48. It deals only with the motion of bodies without reference to the forces that cause them. What is this? a) Dynamics b) Kinetics c) Kinematics d) Static 49. It is the circle on gear that corresponds to the contact surface of the friction wheel. How do you call this circle? a) Pitch circle b) Addendum circle c) Base circle d) Dedendum circle

50.

It is the circle drawn through the top of the gear tooth; its center is at the gear center. What is this circle?

8

Machine Design & Shop Practice

51. 52. 53.

54. 55.

56. 57.

58. 59.

60. 61. 62. 63. 64.

65. 66. 67. 68. 69. 70. 71. 72. 73. 74.

Refresh Trivia # 1

a) Pitch circle b) Addendum circle c) Base circle d) Dedendum circle What is the radial distance from the pitch circle to the addendum circle of a spur gear? a) Addendum b) Dedendum c) Clearance d) Space width This circle is drawn through the bottom of the gear tooth; its center is at the gear center. What do you call this circle? a) Pitch circle b) Addendum circle c) Base circle d) Dedendum circle The largest circle centered at the gear center, which is not penetrated by the teeth of the mating gear. It is a circle tangent to the addendum circle of the mating gear. What is this circle? a) Pitch circle b) Addendum circle c) Clearance circle d) Dedendum circle This radial distance of a gear is measured from the clearance circle to the root circle, and is the difference between the dedendum of one gear and addendum of the mating gear. What is this radial distance? a) Addendum b) Dedendum c) Clearance d) Space width This radial distance in a gear is measured between the addendum and dedendum circle, snd is the sum of the addendum and the dedendum? How do you call this distance? a) Addendum b) Whole depth c) Working depth d) Space width This minimum distance is measured between the non-driving side of a tooth and the adjacent side of the mating tooth. It is the amount by which the width of a tooth space exceeds the thickness of the engaging tooth measured on the pitch circle. What is this distance? a) Circular pitch b) Whole depth c) Backlash d) Space width It is an arc of the pitch circle of a spur gear through which a tooth travels from the first point of contact with the mating tooth to the point where the contact ceases. What is this arc? a) Arc of action b) Arc of approach c) Tooth profile d) Involute curve It is an arc of the pitch circle of a spur gear through which a tooth travels from the point of contact with the mating tooth to the pitch point. What is this arc? a) Arc of action b) Arc of approach c) Arc of recess d) Involute curve What is an arc of the pitch circle of a spur gear through which a tooth travels from its contact with the mating tooth at the pitch point where the contact ceases? a) Arc of action b) Arc of approach c) Arc of recess d) Involute curve What is the angle between the line drawn from the pitch point perpendicular to the line of centers and the line drawn from the pitch point to the point where a pair of teeth of gears is in contact? a) Pressure angle b) Helix angle c) Lead angle d) Angle of approach How do you call the circle from which an involute tooth of a spur gear is generated or developed? a) Pitch circle b) Addendum circle c) Base circle d) Dedendum circle What do you call an angle in the base cylinder of an involute spur gear that the tooth makes with the gear axis? a) Pressure angle b) Base helix angle c) Lead angle d) Angle of approach What is the pitch on the base circle or along the line of action of an involute spur gear?. a) Axial base pitch of an involute gear b) Normal pitch of an involute gear c) Angle of approach of an involute gear d) Base pitch of an involute gear This is the distance between the parallel axes of spur gears or parallel helical gears, or the distance between the crossed axes of helical gears and worm gears. It can be defined also as the distance between the centers of pitch circles. What is this distance? a) Addendum b) Center distance c) Clearance d) Space width This is the width of the tooth measured along the pitch circle. How do you call this tooth width of a gear? a) Circular thickness b) Chordal thickness c) Tooth space d) Face width The tooth width measured along the chord at the pitch circle is known as: a) Circular thickness b) Chordal thickness c) Tooth space d) Face width The space between teeth measured along the pitch circle is called: a) Circular thickness b) Chordal thickness c) Tooth space The length of teeth in an axial direction is called as: a) Circular thickness b) Chordal thickness c) Tooth space The surface of the tooth between the pitch cylinder and the addendum cylinder is said to be: a) Tooth face b) Chordal thickness c) Tooth space The surface of the tooth between the pitch and root cylinders is said to be: a) Circular thickness b) Tooth flank c) Tooth space The surface of the top of the tooth of a gear is known as: a) Tooth top land b) Tooth bottom land The surface of the bottom of the tooth space is said to be: a) Circular thickness b) Chordal thickness

d) Face width d) Face width

d) Face width d) Face width

c) Tooth space

d) Face width

c) Tooth space

d) Tooth bottom land

Circular Pitch is the distance measured along the pitch circle from a point on one tooth to the corresponding point on the adjacent tooth of the gear. a) Circular thickness b) Diametral pitch c) Circular pitch d) Tooth bottom land It is the number of teeth per inch of the pitch diameter. This is also a number or parameter used to determine the sizes of gears in the English system.

9

Machine Design & Shop Practice a) Circular thickness

75. 76.

77. 78. 79. 80. 81.

Refresh Trivia # 1 b) Diametral pitch

c) Circular pitch

d) Module

The ratio of the pitch diameter to the number of teeth; it is a number used to determine and specify gear sizes in the metric system. a) Circular thickness b) Diametral pitch c) Circular pitch d) Module “The shape (profile) of the tooth of a gear must be such that the common normal at the point of contact between two teeth always passes through a fixed point on the line of centers of the gears.” The preceding statement is known as: a) Grashof’s law b) Coriolli’s law c) Klein’s law d) Fundamental law of gearing A curve described by a point on a circle that rolls internally or externally on another circle is said to be: a) Arc of action b) Arc of approach c) Involute curve d) Cycloid curve The path generated by a tracing point on a cord as the chord is unwrapped from a cylinder called the base cylinder a) Arc of action b) Arc of approach c) Involute curve d) Cycloid curve For two externally meshing gears, which of the following is incorrect? a) The same direction of rotation b) The same diametral pitch c) The same circular pitch d) The same addendum For two internally mashing gears, which of the following is incorrect? a) Opposite directions of rotation b) The same diametral pitch c) The same circular pitch d) The same addendum A rotating or stationary member, usually of circular cross section much smaller in diameter than its length, used to transmit motion or power; having mounted on it such power-transmitting elements as gears, pulleys, belts, chains, cam, flywheels, cranks, sprockets, and rolling-element bearings. a) Gear b) Flywheel c) Shaft d) Cam

82.

A non-rotating member that carries no torque and is used to support rotating wheels, pulleys, and the like. a) Spindle b) Axle c) Line shaft d) Counter shaft 83. The geometric shape of bevel gears based on equivalent rolling contact is known as: a) Pitch cone b) Cone distance c) Face cone d) Root cone

84. The intersection of the elements making up the pitch cone is called as: a) Pitch cone b) Cone distance c) Apex of pitch cone 85. A slant height of the pitch cone. It is the length of a pitch cone element. a) Pitch cone b) Cone distance c) Apex of pitch cone

d) Root cone d) Root cone

86. The cone formed by the elements passing through the top of the teeth and the apex is known as: a) Pitch cone b) Cone distance c) Face cone d) Root cone 87. The cone formed by the elements passing through the bottom of the teeth and the apex is said to be: a) Pitch cone b) Cone distance c) Apex of pitch cone d) Root cone 88. The angle between an element of the face cone and the axis of the gear is known as: a) Face angle b) Pitch angle c) Pitch angle d) Root angle 89. The angle between an element of the pitch cone and the axis of the gear is called as: a) Face angle b) Pitch angle c) Pitch angle d) Root angle 90. It is the angle between an element of the root cone and the axis of the gear. a) Face angle b) Pitch angle c) Pitch angle d) Root angle 91. It is the width of a tooth of a bevel gear. How do you call this? a) Face width b) Addendum c) Apex d) Dedendum 92. It is the distance from an element on the pitch cone to an element on the face cone, measured on the outside of the tooth. What is this distance? a) Face width b) Addendum c) Apex d) Dedendum 93. It is the distance from an element on the pitch cone to an element on the root cone, measured on the outside of the gear. How do you call this distance? a) Face width b) Addendum c) Apex d) Dedendum 94. It the angle between an element on the pitch cone and an element on the face cone. a) Addendum angle b) Dedendum angle c) Pitch angle d) Root angle 95. The angle between an element on the pitch cone and an element on the root cone is known as: a) Addendum angle b) Dedendum angle c) Pitch angle d) Root angle 96. The pitch diameter measured on the inside of the tooth is said to be: a) Inside pitch diameter b) Outside pitch diameter c) Back cone diameter d) Root cone diameter 97. It is the pitch diameter measured on the outside of the tooth. a) Inside pitch diameter b) Outside pitch diameter c) Back cone diameter d) Root cone diameter 98. Fatigue strength is increased by repeated loads just below the normal fatigue limit, followed by small step by step increases of the loading, the process is called as: a) Mixing b) Coaxing c) Axing d) Relieving 99. It is the diameter of the imaginary cylinder that bounds the crest of an external thread and the roots of an internal thread. a) Mean diameter b) Stress diameter c) Minor diameter d) Major diameter 100. It is a type of bolt distinguished by a short portion of shank underneath the head being square or finned or ribbed. a) Coupling bolt b) Machine bolt c) Stud bolt d) Carriage bolt 101. A type of bolt threaded on both ends and can be used where a through bolt is impossible. a) Coupling bolt b) Machine bolt c) Stud bolt

10

d) Carriage bolt

Machine Design & Shop Practice

Refresh Trivia # 1

102. If the band wraps partly around the brake wheel or drum, and braking action is obtained by pulling the band tight onto the wheel. a) Block brake b) Band brake c) Clutch d) Centrifugal brake 103. A clutch has a disadvantage of heavier rotating masses. a) Multiple disc clutch b) Disc clutch 104. Devise used to measure an accurate speed: a) Speedometer b) Dial Indicator

c) Cone clutch

d) Band brake

c) Tachometer

d) Dial Gauge

105. When the hole is smaller than shaft, it will take pressure to put the parts together. The allowance is said to be negative and is termed as: a) Negative tolerance b) Negative allowance c) Negative fits d) Interference of metal 106. When two elastic bodies collide, which of the following laws can be used to solve for the resulting velocity? a) Dalton’s law b) Avogadro’s law c) Conservation of energy d) Conservation of momentum and conservation of energy 107. The ability of a metal to be deformed considerably without rapture is called as: a) Plasticity b) Ductility c) Malleability 108. Permanent deformation or strain may occur without fracture: a) Malleability b) Elasticity c) Ductility

d) Plasticity

109. It is a science of motion that can be solved in terms of scalar or vector algebra: a) Kinematics b) Curvilinear translation c) Projectiles

d) Acceleration

d) Rigidity

110. A system of forces in space is in equilibrium. If two equal and opposite collinear forces are added, which of the following if any is true? a) Equilibrium is destroyed b) Equilibrium is maintained c) An unbalanced of moment exist d) None of these is true

11

MACHINE DESIGN/SHOP PRACTICE

JCSF ENGINEERING REVIEW CENTER 2nd Floor Santos-Causing Building, National Highway Halang, City of Calamba, Laguna

MACHINE DESIGN AND SHOP PRACTICE (Refreshers Trivia # 2) Prepared by: Jose R. Francisco, PME March 2012 MULTIPLE CHOICE QUESTIONS Select the best answer from each of the following questions. On the answer sheet provided, shade the box that corresponds to your choice. Strictly no erasures allowed. 1.

Select a deep-groove ball bearing to carry a radial load Fx = 800 lb and a thrust load Fz = 700 lb at 1800 rpm. The service is 8 hr/day, but it is not continuous; design for 18 250 hr. The operation is smooth with little vibration; the outer ring rotates. Determine the design life in million revolution (mr) with no more than 10 % failure. a) 1791 mr b) 1971 mr c) 1197 mr d) 1917 mr Solution:

2.

(18 250)(60)(1 800) 10 6

= 1971 mr

If the ultimate shear strength of a steel plates is 42 000 psi, what force is necessary to punch a 0.75 inch diameter hole in a 0.625 inch thick plate? a) 61 850 lb b) 65 810 lb c) 61 580 lb d) 60 185 lb Solution:

3.

B10 = (Hrs )(60 min s / hr )(rpm ) =

(

)

F = s u A s = s u (πd t ) = 42000 lb / in 2 (π )(0.75 in )(0.625 in ) = 61 850.1 lb

Find the pressure required to punch a 1-inch square hole in ¼ -inch thick steel. a) 20.67 tons b) 26.76 tons c) 26.67 tons Solution:

o

d) 26.67 tons

⎛ 4⎞⎛ 1 ⎞ F = 80 D T = 80⎜ ⎟ ⎜ ⎟ = 26.67 tons ⎝ 3⎠⎝ 4⎠

Pressure Required for Punching.—The formula for the force in tons required to punch a circular hole in sheet steel is, F =

π D ss t 2 000

, where ss =

the shearing strength of the material in psi; t = thickness of the steel in inches, and 2000 is the number of lb in 1 ton. An approximate formula is,

F = D t (80) , where D and T are the diameter of the hole and the thickness of the steel, respectively, both in inches, and 80 is a factor for steel.

o o

4.

The result is the force in tons. If the hole is not circular, replace the hole diameter with the value of one-third of the perimeter of the hole to be punched. The corresponding factor for punching holes in brass is 65 instead of 80. (Source: Machinery’s Handbook 26, p1303)

What length of a square key is required for a 4-in diameter shaft transmitting 1000 hp at 1000 rpm? The allowable shear and compressive stresses in the key are 15 ksi and 30 ksi, respectively. a) 2.1 inches b) 2.8 inches c) 3.2 inches d) 4.2 inches Solution: Transmitted torque, T =

63000 Hp 63000(1000 ) = = 63 000 in ⋅ lb n 1000

D , for good proportion 4 2T 2 (63 000 ) = = 2.1 inches Key length based on shear, L = s s bD 15 000 (1)(4)

Key width,

b≈

Key length based on compression, 5.

Therefore, use L = 2.1 inches

nb =

8T 8 (15 000) = = 8.5 bolts 2 π s sb d D b π (3000 )(0.5)2 (6 )

Use, nb = 9 bolts

Determine the radius of gyration of a wheel that has an outside and inside diameters of 1 meter and 0.75 meter, respectively? Neglect its hub and arms. a) 0.5125 m b) 0.6125 m c) 0.3125 m d) 0.4125 m Solution: k =

7.

4T 4 (63 000 ) = = 2.1 s c t D 30 000 (1)(4)

A flange coupling is to transmit 15,000 in-lb between two 2.5” diameter shafts. How many ½” diameter bolts in a 6” diameter bolt circle are required if the shear stress in each bolt is limited to 3000 psi? a) 9 bolts b) 7 bolts c) 6 bolts d) 8 bolts Solution: No. of bolts,

6.

L=

I = A

( (

) )

π D o4 − D i4 64 = π 2 D o − D i2 4

1 16

(

)(

⎡ D o2 + D i2 D o2 − D i2 ⎢ ⎢⎣ D o2 − D i2

)⎤⎥ = 1 ⎥⎦

4

D o2 + D i2 = 0.3125 in .

What is the polar section modulus of a solid shaft with a diameter of 101.6 mm? 3 4 3 b) 209.5 cm c) 205.9 cm a) 209.5 cm

1

4

d) 205.9 cm

MACHINE DESIGN/SHOP PRACTICE

8.

If the ultimate shear strength of a steel plates is 42 000 psi, what force is necessary to punch a 0.75 inch diameter hole in a 0.625 inch thick plate? a) 61 850 lb b) 65 810 lb c) 61 580 lb d) 60 185 lb Solution:

9.

J 2J π 3 π = = D = (10.16 )3 = 205.9 cm 3 c D 16 16

Zj =

Solution:

(

)

F = s u A s = s u (πd t ) = 42000 lb / in 2 (π)(0.75 in )(0.625 in ) = 61 850.1 lb

Determine the tensile stress area of an American Standard Screw Threads 6-32 UNC with basic major diameter of 0.1380 inch. -3 2 -2 2 -4 2 -5 2 b) 9.085 x 10 in c) 9.085 x 10 in d) 9.085 x 10 in a) 9.085 x 10 in

⎛

Solution: For American Standard Screw Threads: A t = 0.7854⎜ D −

⎝

0.9743 ⎞ ⎟ n ⎠

2

2

Where At = tensile Stress Area, in ; D = basic major diameter, in.; n = no. of threads per inch 2

0.9743 ⎞ ⎛ A t = 0.7854⎜ 0.1389 − ⎟ = 9,085 x 10 −3 in 2 28 ⎠ ⎝ 10. What is the number of threads per mm and the tensile stress area of a standard Metric screw Thread designated by M10 x 1.5? 2 2 2 2 c) 1.5 and 57.99mm d) 1.75 and 57.99 mm a) 0.555 and 57.99 mm b) 0.667 and 57.99 mm Solution:

n=

1 1 = = 0.667 threads per mm p 1.5

For Standard Metric Screw Threads,

A t = 0.7854(D − 0.9383p )2 = 0.7854[10 − 0.9383(2.5)]2 = 57.99 mm 2

2

D = basic major diameter, mm; p = pitch, mm Where At = tensile stress Area, mm ; Note: M stands for standard metric screw threads; 10 stands for the basic major diameter, which is 10 mm; 1.5 stands for pitch that is 1.5 mm. 11. A line shaft is to transmit 200 Hp at 900 rpm. Find the diameter of the shaft. a) 2.18 inches b) 2.28 inches c) 3.18 inches d) 3.28 inches Solution:

D=3

53.5 P 53.5(200 ) =3 = 2.28 inches N 900

Note: For Main Power Transmitting Shaft:

For Small, Short Shaft:

P=

P=

D3N 38

D3 N 80

Where,

For Line Shaft Carrying Pulleys:

P = transmitted power, Hp

P=

N = shaft rpm

D3N 53.5 D = shaft diameter, in inches

12. A 1.75-inch-diameter shaft is supported by two sleeve bearings. The total load on the two bearings is 2800 lb. Find the friction power loss, in Hp, if the coefficient of friction between shaft and bearing is 0.10 and the shaft rotates 200 rpm. a) 0.88 Hp b) 0.78 Hp c) 0.98 Hp d) 0.68 Hp

Solution:

T n f Fr n fHp = f = = 63 000 63 000

⎛ 1.75 ⎞ 0.10(2 800)⎜ ⎟(200 ) ⎝ 2 ⎠ = 0.78 (63 000)

F = load, lb n = rpm r = bearing diameter, inches Tf = frictional torque, in-lb f = coefficient of friction 13. Determine the Hp lost when a collar is loaded with 2000 lb, rotates at 50 rpm, and has a coefficient of friction of 0.15. The outside diameter of the collar is 4 inches and the inside diameter is 2 inches. a) 0.7314 Hp b) 0.3714 Hp c) 0.4713 Hp d) 0.4371 Hp Where,

Solution:

Where,

fHp =

rf =

Tf n f W rf n 0.15(2000 lb )(1.56 inches )(50 rpm ) = = = 0.3714 63000 63000 63000

3 3 2 ⎛⎜ ro − ri ⎞⎟ 2 ⎡ (2 )3 − (1)3 ⎤ = ⎢ ⎥ = 1.56 inches 3 ⎜ ro2 − ri2 ⎟ 3 ⎢⎣ (3)2 − (1)2 ⎥⎦ ⎝ ⎠ 2

14. A vertical steel cylinder water tank is 30 m in diameter and 45 m high. The allowable stress of the steel plate is 1224 kg/cm . Without reinforcing angle bars and rods, what is the thickness of the steel plate? a) 55.15 mm b) 51.55 mm c) 65.15 mm d) 61.55 mm Solution: Where,

t=

(

)

pD 441 297 N / m 2 (30 m ) = = 0.05515 m = 55.15 mm 2 s t E j 2 1224 kg / cm 2 (9.8066 N / kg )(100 cm / m )2

(

)

p = maximum pressure inside the tank, Pa

(

)(

)

p = ρ g H = 1000 kg / m 3 9.8066 m / s 2 (45 m ) = 441 297 Pa

st = hoop stress of the tank, Pa 15. What is the bursting steam pressure of a hemispherical steel shell with a diameter of 100 inches and made of 0.0635-m thick steel plate, if the joint efficiency is 70 % and the tensile strength is 60 000 psi? a) 4 020 psi b) 4 200 psi c) 2 400 psi d) 2 040 psi

Solution:

p=

4 t sl E j D

(

)

⎛ 63.5 ⎞ 4⎜ in ⎟ 60 000 lb / in 2 (0.70 ) ⎝ 25.4 ⎠ = = 4 200 psi 100 in.

2

MACHINE DESIGN/SHOP PRACTICE Where, p = bursting pressure, psi t = shell thickness, inches

sl = shell stress, psi D = shell diameter, inches

Ej = joint efficiency

Note: For the longitudinal stress of the thin-walled cylinder, and the stress for spherical tank:

pD sL = 4tEj

16. The root diameter of a double square thread is 0.55 inch. The screw has a pitch of 0.2 inch. Find the outside diameter and the number of thread per inch. p a) 0.2 threads/inch b) 10 threads/inch c) 5 threads/inch d) 2.5 threads/inch Solution: Solving for the outside or major diameter, Do = Di + p = 0.55 + 0.2 = 0.75 inch Solving for the number of threads per inch,

TPI =

1 1 = = 5 threads / inch p 0.2

Di = 0.55”

Lead

17. A flat belt is 6 inches wide and 1/3 inch thick and transmits 15 Hp. The center distance is 8 ft. The driving pulley is 6 inches in diameter and rotates at 2 3 000 rpm such that the loose side of the belt is on top. The driven pulley is 18 inches in diameter. The belt material is 0.035 lb/in and the coefficient of friction is 0.30. Determine the belt net tension. a) 175.5 lb b) 157.5 lb c) 155.7 lb d) 165.7 lb

F = F1 − F2 =

Solution:

2 T 2 ⎛ 63 000 Hp ⎞ ⎛ 2 ⎞ ⎡ 63 000(15) ⎤ = ⎜ ⎟ = ⎜ ⎟⎢ ⎥ = 157.5 lb D D⎝ n ⎠ ⎝ 6 ⎠ ⎣ 2 000 ⎦

⎛ 6⎞ ⎟(2 000) = 3141.59 fpm ⎝ 12 ⎠

Other Solution: Vm = π D n = π⎜

F = F1 − F2 =

33 000 Hp 33 000(15) = = 157.56 lb Vm 3141.59

18. A roller chain and sprocket is to drive vertical centrifugal discharge bucket elevator. The pitch of chain connecting sprockets is 1.75”. The driving sprocket is rotating at 120 rpm and has 11 teeth while the driven sprocket is rotating at 38 rpm. Determine the number of teeth of driven sprocket. a) 33 teeth b) 35 teeth c) 30 teeth d) 34 teeth

⎛n T2 = T1 ⎜⎜ 1 ⎝ n2

Solution:

⎞ 120 ⎞ ⎟ = (11)⎛⎜ ⎟ = 34.74 ≈ 35 teeth ⎟ 38 ⎠ ⎝ ⎠

19. A helical steel spring has a maximum load of 800 lb and a corresponding deflection of 2 inches. If it has 8 active coils and an index of 6, what minimum shear strength of the spring material is required? a) 57 ksi b) 47 ksi c) 67 ksi d) 37 ksi Solution:

k=

F GD w = δ 8C3 N c

Wahl Factor,

Dw =

Kw =

Torsional stress,

8C3 N c F 8 (6 ) (8)(800) = = 0.477 inch δG 2 11.6 x 106 3

(

4C − 1 0.615 4(6) − 1 0.615 + = + = 1.2525 4C − 4 C 4(6) − 4 6

⎛ 8FC s s = K w ⎜⎜ 2 ⎝ π Dw

)

⎡ 8 (800 )(6) ⎤ ⎞ ⎟ = 1.2525⎢ = 67 286 psi 2⎥ ⎟ ⎠ ⎣ π (0.477 ) ⎦

20. A helical-coil spring has a mean coil diameter of 1 inch and a wire diameter of 1/8 inch. Determine the value of Bergstrasssar factor of the spring. a) 1.172 b) 1.712 c) 1.217 d) 1.271 Solution:

C=

Dm 1 = =8 1 d 8

KB =

4C + 2 4(8) + 2 = = 1.1724 4C − 3 4(8) − 3

21. A precision cut gear transmits 25 Hp at a pitch line velocity of 6000 fpm. If the service is intermittent, find the dynamic load. a) 247.05 lb b) 274.05 lb c) 275.04 lb d) 247.05 lb Solution:

Ft =

33 000 Hp (33 000 )(25) = = 137.5 lb Vm 6 000

⎛ 78 + Vm Fd = ⎜ ⎜ 78 ⎝

⎞ ⎛ ⎟ F = ⎜ 78 + 6000 d ⎟ ⎜ 78 ⎝ ⎠

⎞ ⎟ (137.5) = 274.05 lb ⎟ ⎠

22. What is the difference of the values of the Wahl factor and the Bergstrasser factor, in percentage? a) 1 % b) Less than 1 % c) Greater than 1 % d) 0.5 % 23. A double-thread worm has a pitch diameter of 3 inches. The wheel has 20 teeth and a pitch diameter of 5 inches. Find the gear helix angle. o o o o b) 9.46 c) 6.49 d) 6.94 a) 4.69

⎡⎛ T λ = tan −1 ⎢⎜⎜ w ⎢⎣⎝ Tg

Solution:

⎞⎛ D g ⎟⎟⎜ ⎜ ⎠⎝ D w

⎞⎤ ⎡ ⎤ ⎟⎥ = tan −1 ⎢ 2 ⎛⎜ 5 ⎞⎟⎥ = 9.46 o ⎟ ⎣ 20 ⎝ 3 ⎠⎦ ⎠⎥⎦

24. A helical-coil spring has a mean coil diameter of 1 inch and a wire diameter of 1/8 inch. Determine the shear-stress augmentation factor of the spring. a) 1.625 b) 1.0625 c) 1.0256 d) 1.0526 Solution:

C=

Dm 1 = =8 1 d 8

Ks =

2C + 1 2(8) + 1 = = 1.0625 2C 2(8) 3

MACHINE DESIGN/SHOP PRACTICE 25. A disc clutch has 6 pairs of contacting friction surfaces with an outside diameter of 200 mm and an inside diameter of 100 mm. The coefficient of friction of the clutch materials is 0.4 and the axial force is 1500 N. The shaft speed is 1200 rpm. Determine the Hp that can be transmitted by the clutch assuming uniform pressure. a) 35.2 Hp b) 23.5 Hp c) 47.2 Hp d) 27.4 Hp 3 3 2 ⎛⎜ ro − ri ⎞⎟ ⎛ 2 ⎞ ⎡ (100 )3 − (50)3 ⎤ = ⎜ ⎟⎢ ⎥ = 77.78 mm 3 ⎜ ro2 − ri2 ⎟ ⎝ 3 ⎠ ⎢⎣ (100 )2 − (50)2 ⎥⎦ ⎝ ⎠

Friction Radius (Uniform pressure), rf =

Solution:

Friction Power or Transmitted Power or Power Capacity,

P=

π n Tf πn (Ff rf n f ) = π n (f Fa rf n f ) = π(1200) (0.4)(1.5)(0.07778)(6) = 30 30 30 30

P = 35.19 kW = 47.2 Hp P = power capacity, kW Ff = friction force, kN Rf = friction radius or mean radius, m Fa = axial load, kN

Where,

Tf = torque capacity, kN-m nf = no. of pairs of contacting friction surfaces

26. A flywheel has a mean diameter of 4 ft and is required to handle 2250 ft-lb of kinetic energy. It has a width of 8 inches, mean operating speed is 300 rpm and the coefficient of fluctuation is to be 0.05. Find the weight of rim, assuming that the arms and hub are equivalent to 10 % of the total rim weight. The flywheel is made up of cast iron with specific weight of 0.26 lb per cubic inch. a) 333.7 lb b) 373.3 lb c) 337.3 lb d) 733.3 lb Solution: ∆KE =

Where,

1.10 W Cf V 2 g

g (∆KE )

W=

1.10 C f V

V = mean velocity =

2

=

32.2(2250 )

1.10(0.05)(62.83)2

πDn π(4 )(300) = = 62.83 fps 60 60

g = acceleration due to gravity = 32.2 fps

= 333.7 lb

Cf = coefficient of fluctuation ∆KE = Kinetic Energy

2

o

27. A 20 involute spur gear has a tooth whole depth of 16.95 mm, a tooth thickness of 13.2 mm, and a pitch of 3. Determine the circular pitch of the gear. a) 26.6 mm b) 16.6 mm c) 25.6 mm d) 24.6 mm Solution:

Pc =

π π = = 1.0472 inches = 26.6 mm Pd 3 o

28. A parallel helical gear-set consists of a 19-tooth pinion driving a 57-teeth gear. The pinion has a left-hand helix angle of 20 , a normal pressure angle of o 14½ , and a normal diametal pitch of 10 teeth/inch. If the pinion is to transmit 50 Hp at a speed of 1750 rpm. Determine the center distance of the two gears. a) 2.02 inches b) 6.06 inches c) 4.04 inches d) 2.06 inches Solution: Pdn =

Tp Tg Pd = = cos ψ D p cos ψ D g cos ψ

Pitch diameter of the pinion, D p =

⎛ Tg ⎜ Tp ⎝ D p + Dg

Pitch Diameter of the gear, D g = D p ⎜ Center-to-center distance, C =

2

Tp Pdn cos ψ

=

19 10 cos 20 o

= 2.02 inches

⎞ ⎟ = 2.02⎛⎜ 57 ⎞⎟ = 6.06 inches ⎟ ⎝ 19 ⎠ ⎠ =

2.02 + 6.06 = 4.04 inches 2

29. A right-handed single-thread hardened-steel worm has a catalog rating of 2.25 kW at 650 rpm when meshed with a 48-tooth cast-steel gear. The axial o pitch of the worm is 25 mm, normal pressure angle is 14.5 , and the pitch diameter of the worm is 100 mm. The coefficient of friction is 0.085. Determine the shafts center distance. a) 241 mm b) 142 mm c) 412 mm d) 124 mm Solution:

Speed Ratio, SR = Tanλ =

Tg D g cos λ Dg ωw n w = = = = ωg ng Tw D w sin λ D w tan λ

p L 25 = = = 0.07958 πD w πD w π(100 )

→ λ = 4.55 o

⎛ Tg ⎞ ⎛T ⎞ ⎛ ⎞ ⎛T ⎟ D tan λ = ⎜ g ⎟D w ⎜ p ⎟ = ⎜ g ⎜ πD ⎟ ⎜ T ⎜T ⎟ w ⎜T ⎟ w ⎠ ⎝ w ⎝ ⎝ w⎠ ⎝ w⎠ D w + D g 100 + 381.97 = = 241 mm Center Distance, C = 2 2

Pitch diameter of the gear, D g = ⎜

⎞⎛ p ⎞ ⎛ 48 ⎞⎛ 25 ⎞ ⎟⎜ ⎟ = ⎜ ⎟⎜ ⎟ = 381.97 mm ⎟⎝ π ⎠ ⎝ 1 ⎠⎝ π ⎠ ⎠

o

30. A 20 straight-tooth bevel pinion having 14 teeth and a diametral pitch of 6 teeth/inch drives a 42-tooth gear. The two shafts are at right angles and in the same plane. Find the pitch angle of the pinion. o o o o b) 20 c) 14.5 d) 20.5 a) 18.4 Solution: γ = tan

⎛ Tp ⎜ Tg ⎝

−1 ⎜

⎞ ⎟ = tan −1 ⎛⎜ 14 ⎞⎟ = 18.4 o ⎟ ⎝ 42 ⎠ ⎠ o

31. A triple-thread worm has a lead angle of 17 and a pitch diameter of 2.2802 inches. Find the center distance when the worm is mated with a wheel of 48 teeth. a) 6.72 inches b) 7.26 inches c) 6.27 inches d) 7.62 inches

4

MACHINE DESIGN/SHOP PRACTICE

⎛ Tg ⎞ ⎟D tan λ = ⎛⎜ 48 ⎞⎟(2.2802 ) tan 17 o = 11.154 inches Solution: D g = ⎜ ⎜T ⎟ w ⎝ 3 ⎠ ⎝ w⎠

C=

Dw + Dg 2

=

2.2802 + 11.154 = 6.72 inches 2

o

32. A 36-tooth pinion turning at 300 rpm drives 120-tooth gear of 14.5 involute full depth pressure angle. Determine the rpm of the driven gear. a) 60 rpm b) 45 rpm c) 75 rpm d) 90 rpm

⎛ Tp ⎞ ⎟ = (300 )⎛⎜ 36 ⎞⎟ = 90 rpm ⎟ T ⎝ 120 ⎠ g ⎝ ⎠

Solution: n g = n p ⎜ ⎜

33. A single square thread power screw is to raise a load of 70 kN. The screw has a major diameter of 36 mm and a pitch of 6 mm. The coefficient of thread friction and collar friction are 0.13 and 0.10 respectively. If the collar mean diameter is 90 mm and the screw turns at 60 rpm, find the axial linear speed of the screw. a) 5 mm/s b) 6 mm/s c) 7 mm/s d) 5.5 mm/s Solution: For the linear speed of the screw, Vn = n (L) = (60 rpm)(6 mm/rev) = 360 mm/min = 6 mm/s 34. What is the minimum clearance allowed for meshing spur gears with diametral pitch of 20? The spur gear has 25 teeth. a) 0.00785 inch b) 0.00758 inch c) 0.00857 inch d) 0.00758 inch Solution:

c=

0.157 0.157 = = 0.00785 inch pd 20

(Vallance, page 262)

35. A wire rope lifts a load of 10 kips at a maximum speed of 1000 feet per minute, attained in 5 seconds starting from rest. The rope has a metallic cross 2 sectional area of 0.4 in . Determine the maximum tensile stress on the rope in ksi. a) 26.2 b) 25.0 c) 27.6 d) 32.4 Solution:

a=

V1 − Vo (1000 / 60 ) − 0 = = 3.33 fps 2 t 5 St =

⎛ a⎞ 3.33 ⎞ ⎛ F = WL ⎜⎜1 + ⎟⎟ = (10 000) ⎜1 + ⎟ = 11 034.16 lb g 32 .2 ⎠ ⎝ ⎝ ⎠

11,034.16 = 27 585.4 psi = 27.6 ksi 0.4

36. A casting weighing 300 pounds is to be lifted by means of an overhead crane. The casting is lifted 10 feet in 12 seconds. What is the horsepower developed? a) 0.54 b) 0.84 c) 0.95 d) 0.45

⎛ ⎜

⎞ ⎟ 1hp ⎟ = 0.4545hp ⎣12 sec ⎦ ⎜ 550 ft − lb ⎟ ⎜ ⎟ sec ⎠ ⎝

Solution: Power = (Force)(Velocity) = 300lb ⎡ 10ft ⎤ ⎜ ⎢ ⎥

37. What wall thickness is required for a 500mm diameter cylinder under an internal pressure of 20 MPa? Use a design stress of 80 MPa. a) 73 mm b) 53 mm c) 63 mm d) 83 mm Solution: Using thin-walled vessel formula:

St =

for

t ≤ 0.07 D

pD 20(500) t > 0.07,∴ use the thick − walled formula : 80 = : t = 62.5 mm but 2t 2t D D ⎡ S + p ⎤ 500 ⎡ 80 + 20 ⎤ t= ⎢ − 1⎥ : t = 72.7mm − 1⎥ = ⎢ 2 ⎢⎣ 80 − 20 ⎥⎦ 2 ⎢⎣ S − p ⎥⎦

38. This type of spring incorporates a standard helical compression spring with two looped wire devices inserted through the inside of spring. a) Helical compression spring b) Drawbar spring c) Helical extension spring d) Leaf spring 39. In a straight bevel gear, how do you call the angle between an element on the pitch cone and an element on the face cone? a) Face angle b) Pitch angle c) Addendum angle d) Dedendum angle 40. How do you call a large wood screw that is used to fasten machinery and equipment to a wooden base? a) Lag screw b) Wood screw c) Log screw d) Square screw o o 41. A journal bearing with angle of contact of the bushing or bearing with the journal is 180 or less, 120 is the common value. a) Partial journal bearing b) Full journal bearing c) Clearance journal bearing d) Concentric journal bearing 42. A journal bearing where the radius of the journal is less than the radius of the bushing or bearing. a) Fitted journal bearing b) Clearance journal bearing c) Full journal bearing 43. It refers to the thickness of the space allowed for the lubricant that separates the parts having relative motion. a) Radial clearance b) Diametral clearance c) Film thickness

d) Partial journal bearing d) Clearance

44. A journal bearing where the radii of the journal and the bushing are equal; it must be a partial bearing and the journal must run eccentric with the bushing in order to provide space for the lubricant. a) Fitted journal bearing b) Clearance journal bearing c) Full journal bearing d) Partial journal bearing 45. A partial journal bearing where the line of action of the load or bearing reaction is bisecting the arc of the partial bearing. a) Partially loaded bearing b) Eccentrically loaded bearing c) Centrally loaded bearing d) Fully loaded bearing 46. A journal bearing where the line of action of the load is passing to one side of the center. a) Centrally loaded bearing b) Eccentrically loaded or offset bearing c) Fully loaded bearing d) Partially loaded bearing 47. Which of the following threads are used for power screw?

5

MACHINE DESIGN/SHOP PRACTICE a) Square thread, Acme thread, & Unified thread b) Acme thread, Unified thread, & Buttress thread c) Square thread, Unified thread, & Acme thread d) Square thread, Acme thread, & Buttress Thread 48. A bearing lubrication obtained by introducing the lubricant, which is sometimes air or water, into the load-bearing area at a pressure high enough to separate the surfaces with a relatively thick film of lubricant. This lubrication does not require motion of one surface relative to another. a) Hydrodynamic lubrication b) Hydrostatic lubrication c) Boundary lubrication d) Solid film lubrication 49. An externally threaded fastener intended to be used with nut is said to be a: a) Bolt b) Cap screw c) Allen screw d) Power screw 50. It is a lubrication condition where non-conformal surfaces are completely separated by lubricant film and no asperities are in contact. a) Elastohydrodynamic lubrication b) Solid film lubrication c) Boundary lubrication d) Hydrodynamic lubrication 51. Which of the following are the compositions of stainless steel 302? a) 18 % chromium and 8 % nickel b) 18 % nickel and 8 % chromium c) 18 % chromium and 8 % phosphor bronze d) 18 % bronze and 8 % vanadium 52. These springs are made from one or more flat strips of brass, bronze, steel or other materials loaded as cantilevers or simple beam. a) Torsion springs b) Leaf springs c) Garter springs d) Drawbar springs 53. This refers to the space between adjacent coils when the spring is compressed to its operating length. a) Coil clearance b) Pitch c) Lead d) Deflection 54. This material is the most popular alloy spring steel for conditions involving higher stresses than can be used with the high-carbon steels and for use where fatigue resistance and long endurance are needed; this is also good for shock and impact loads. a) Chrome silicon b) Chrome vanadium c) hard-drawn wire d) Oil-tempered wire 55. For an American Standard Screw Threads, what does 6-32 UNC designate? a) Size 6, 32 threads per inch, coarse thread b) 6 inches basic diameter, 32 threads per inch, coarse thread c) Size 6, 32 threads per inch, fine thread d) 32 inches basic diameter, 6 threads per inch, coarse thread Note: 6 stands for the designated size, 32 stands for the number of threads per inch, UNC stands for Coarse threads 56. It is a Grashof four-bar mechanism in which the shortest link is the frame or fixed link and the other two cranks completely rotate with their axes. How do you call this Grashof four-bar mechanism? a) Drag-link mechanism b) Crank-rocker mechanism c) Double-rocker mechanism d) Triple-rocker mechanism 57.

“For a planar four-bar linkage, the sum of the shortest and longest lengths cannot be greater than the sum of the remaining two link lengths if there is to be a continuous relative rotation between two members.” How do you call the preceding statement? a) Grubler’s Law b) Coriolli’s Law c) Grashof’s Law d) Freudentein’s Law

58. Which of the following is not true for an instant center or centro of planar linkages? a) Centro is a point common to two bodies having the same velocity in each. b) Centro is a point in one body about which another body does not rotate. c) Centro is a point in one body about which another body actually turns. d) Centro is a point in one body about which another body tends to turn. 59. This is the most common work holding device of a shaper machine with the base graduated in degrees that make it possible to swivel any angle. What is this working device? a) Shaper vise b) Parallel bars and hold down bars c) Lathe holder d) Swivel head 60. This is a shaper operation, which is shaping the given stock and having the excess material remain with a tolerable allowance for finishing. How do you call this operation? a) Roughing b) Finishing c) Angular cutting d) Contouring 61. How do you call a cutting tool that has two or more cutting edges as in drill presses and milling machine cutters? a) Grinder b) Single-point cutting tool c) Multi-point cutting tool d) Two point cutting tool 62. This is the trade name for a patented alloy made up chiefly of cobalt, chromium, and tungsten in varying proportions. What is this trade name? a) Stellite b) Carboloy c) Stainless steel d) Copper 63. It is called as the transformation of concepts and ideas into useful machinery. What is this? a) Design b) Synthesis c) Analysis d) Theorem 64. This is a combination of mechanisms and other components that transforms, transmits, or uses energy, load, or motion for a specific purpose. How do yopu call this? a) Mechanism b) Engine c) Machine d) Linkage 65. It is defined as synergistic collection of machine elements; synergistic because as a design it represents an idea or concept greater than the sum of the individual pats. What is this system? a) System of mechanisms b) Mechanical system c) Design system d) Expert system 66. It may be defined as the displacement per length produced in a solid and as the result of stress. How do you call this? a) Deformation b) Elongation c) Strain d) Stress 67. What is the combination of applied normal and shear stresses that produces maximum principal normal stress or minimum principal normal stress, with a third principal stress between or equivalent to the extremes? a) Principal shear stress b) Principal normal stress c) Maximum shear stress d) Bending and shear stresses 68. How do you call a load that is applied transversely to longitudinal axis of member? a) Combined loads b) Concentrated load c) Bending load d) Distributed load 69. It is the capacity of a material to absorb energy when it is deformed elastically and then, upon unloading, to increase this energy. What is this capacity of a material? a) Resilience b) Toughness c) Rigidity d) Ductility 70. How do you call the strain energy per unit volume required to stress a material from an unloaded state to the point of yielding? a) Modulus of roughness b) Modulus of elasticity c) Modulus of rigidity d) Modulus of resilience 71. What is the ability of the material to absorb energy up to fracture? a) Toughness b) Rigidity c) Resilience d) Stiffness

6

MACHINE DESIGN/SHOP PRACTICE 72. What is the other term for the Maximum-Shear-Stress Theory, as a failure prediction theory? a) von Mises criterion b) Tresca yield criterion c) Coulomb-Mohr theory d) Modified Mohr theory 73. It is a failure prediction theory, which states that a part subjected to any combination of loads will fail (by yielding or fracturing) whenever the maximum shear stress exceeds a critical value. How do you call this failure prediction theory? a) Distortion-energy theory b) Maximum-shear-stress theory c) Internal friction theory d) Modified Mohr theory 74. This is a theory in cyclic and impact loading, which states that damage at any stress level, is proportional to number of cycles. What is this theory commonly called? a) Miner’s Rule b) Paris Power Law c) Goodman Rule d) Manson-Coffin Relationship 75. This is a lubrication where the load-carrying surfaces of the bearing are separated by a relatively thick film of lubricant, so as to prevent metal-to-metal contact; and where the stability of the film can be explained by the laws of fluid mechanics. How do you call this type of lubrication? a) Hydrostatic lubrication b) Hydrodynamic lubrication c) Elastohydrodynamic lubrication d) Boundary lubrication 76. How do call the speed at which a rotating shaft becomes dynamically unstable? a) Normal speed b) Variable speed c) Critical speed 77. How do you call a ball bearing with race containing pronounced groove for rolling elements? a) Crown bearing b) Conrad bearing c) Angular-contact bearing

d) Average speed d) Cylindrical bearing

78. This is a machining process for producing internal straight cylindrical surface or profiles, with process characteristics and tooling similar to those for turning operations. What is this machining process? a) Boring b) Drilling c) Reaming d) Milling 79. What is a set of specification for parts, materials, or processes intended to achieve uniformity, efficiency, and a specified quality? a) Code b) Standard c) Law d) Theorem 80. This is a set of specifications for the analysis, design, manufacture, and construction of something; the purpose of which is to achieve a specified degree of safety, efficiency, and performance or quality. How do you call this set of specifications? a) Code b) Standard c) Law d) Theorem 81. How do call the size to which limits or deviations is assigned and is the same for both members of the fit; it is the exact theoretical size? a) Nominal size b) Basic size c) Maximum size d) Minimum size 82. What is the algebraic difference between a size and the corresponding basic size? a) Tolerance b) Allowance c) Deviation d) Limit 83. What is the difference between the maximum and minimum size limits of a part? a) Allowance b) Tolerance c) Deviation d) Basic size 84. What are the stated maximum and minimum dimensions? a) Tolerances b) Limits c) Nominal sizes d) Basic sizes 85. This is a general term that refers to the mating of cylindrical parts such as bolt or a hole; it is used only when the internal member is smaller that the external member. How do you call this? a) Clearance b) Interference c) Allowance d) Tolerance 86. What is the opposite of clearance, for mating cylindrical parts in which the internal member is larger than the external member? a) Clearance b) Allowance c) Tolerance d) Interference 87. These are compounds of metallic elements, most frequently oxides, nitrides, and carbides. a) Plastics b) Polymers c) Ceramics d) Alloy 88. What do you call a material having different properties in all directions at point in solid? a) Isotropic material b) Anisotropic material c) Orthotropic material d) Ceramic material 89. This is a principle or method that a deflection at any point in bar is equal to sum of deflections caused by each load acting separately. How do you call this method or principle? a) Summation Method b) Method of balancing c) Method of superposition d) Shear and Moment diagram method 90. This is the accepted standard wire rope with the wires twisted in one direction to from strands and the strands twisted in opposite direction to form a rope. How do you call this wire rope? a) Improved plow steel wire rope b) Regular lang lay wire rope c) Mild plow steel wire rope d) Long lay wire rope 91. What is a form of correction that develops on highly localized areas on a metal surface? a) Crevice b) Erosion c) Galvanic d) Apitting 92. How do you call the corrosion of iron-base-alloys? a) Rusting b) Crazing c) Chalking d) Fritting 93. Which of the following is the allowable stress that is generally used in practice for main transmitting shafts? a) 8 500 psi b) 4 000 psi c) 6 000 psi d) 6 500 psi 94. What is an equation used to determine the first critical speed of the shaft that overestimates frequency? a) Soderberg Equation b) Rayleigh Equation c) Dunkerly Equation d) Euler Equation 95. This key allows the hub to move along the shaft but prevents the rotation of the shaft. How do you call this key? a) Woodruff key b) Feather key c) Gibs key d) Square key 96. How do you call the ratio of mean diameter of coil and the coil diameter of a spring? a) Wahl number b) Diameter ratio c) Spring index d) Lead angle 97. For ACME thread the pressure angle normal to the thread is equal to: o o o o b) 14.5 c) 13.5 d) 34 a) 12.5 98. It is a low cost spring material, suitable where service is not severe and dimensional precision is not needed. How do you call this spring material? a) Hard drawn wire b) helical spring wire c) Stainless steel d) helical tension spring wire 99. How do you call a spring material that is hard drawn (80 % reduction) but made up of high-grade steel? a) Music wire b) Oil tempered wire c) Song wire d) Chromium-silicon wire 100. It is a design approach where no catastrophic loss can occur as a result of a component failure. What is this design approach? a) Fail-safe design approach b) Fault free analysis approach c) Manifest danger approach d) Redundancy approach

7

MACHINE DESIGN/SHOP PRACTICE Note: The following questions are for your reading and Familiarization SET A 101. In a lathe machine, how do you call the diameter of the largest workpiece that can be rotated in a chuck or between centers without hitting the bed? a) Chuck diameter b) Swing c) Distance between centers d) Spindle diameter 102. How do you call a phenomenon when two touching surfaces have a high contact pressure and when these surfaces have minute relative motion? a) Pre-stressing b) Friction c) Carving d) Fretting 103. What is this part of headstock of a lathe machine used to transmit power from the spindle? a) Motor b) Back gear c) Headstock spindle d) Switch 104. When a hot part is cooled suddenly by quenching, there is momentarily a high temperature gradient that induces a stress gradient. Some metal parts under certain conditions crack as a result. What is this phenomenon? a) Thermal-shock failure b) Thermal fatigue c) Honing d) Quenching 105. When a hot part is cooled suddenly by quenching, there is momentarily a high temperature gradient that induces a stress gradient. Some metal parts under certain conditions crack as a result. How do you call this phenomenon? a) Thermal-shock failure b) Thermal fatigue c) Honing d) Quenching 106. It is the condition of a machine element when it is completely inoperable, cannot perform its intended function adequately, or is unreliable for continued safe use. What do you call this condition? a) Fail-safe condition b) Failure condition c) Critical condition d) Salvage condition 107. How do you call a statistical data used to identify the most likely failure modes? a) Finite element analysis b) Fault free analysis c) Failure analysis d) Random analysis 108. It is a computational method used for solving complex shapes, such as those found in machinery; replaces the complex shape with a set of simple elements interconnected at a finite set of a specific purpose. What is this computational method? a) Finite element analysis b) Numerical method of analysis c) Fault free analysis d) Synthesis 109. It is a design approach where needed service is made apparent before catastrophic failure. How do you call this? a) Manifest danger design approach b) Machine element function approach c) Failure analysis d) Random analysis 110. It is a beam where one end is fixed and other end is free. How do you call this beam? a) Cantilever beam b) Continues beam c) Overhanging beam d) Long beam 111. It is a method used to graphically visualize state of stress acting in different planes passing through a given point. What is this? a) Mohr’s circle b) Soderberg Criterion c) Goodmann’s method d) Gerber’s line criterion 112. This minimum distance is measured between the non-driving side of a tooth and the adjacent side of the mating tooth. It is the amount by which the width of a tooth space exceeds the thickness of the engaging tooth measured on the pitch circle. What is this distance? a) Circular pitch b) Whole depth c) Backlash d) Space width 113. It is an arc of the pitch circle of a spur gear through which a tooth travels from the point of contact with the mating tooth to the pitch point. What is this arc? a) Arc of action b) Arc of approach c) Arc of recess d) Involute curve 114. What is the intersection of the elements making up the pitch cone? a) Pitch cone b) Cone distance c) Apex of pitch cone d) Root cone 115. What do you call a type of bolt threaded on both ends and can be used where a through bolt is impossible? a) Coupling bolt b) Machine bolt c) Stud bolt d) Carriage bolt 116. To avoid excessive wear rate, what is the recommended limiting pressure for 6 x 19 rope for cast iron? a) 200 psi b) 400 psi c) 300 psi d) 500 psi 117. How do you call a type of welding where the arc is covered with a welding composition and a bare electrode wire is fed automatically? a) Resistance welding b) Submerged arc welding c) Induction welding d) Spot welding 118. It is a kind of wear that occurs because of fatigue failure of the surface materials as a result of high contact stresses. What do you call this? a) Slotting b) Pitting c) Involuting d) Curving 119. It is caused by foreign matters, such as grit or metal particles, or by a failure of the oil film at low speed. How do yopu call this? a) Auction b) Scoring c) Abrasion d) Corrosion 120. It occurs when the oil films fails, but in this case, the load and speed are so high that the metal is melted and the metal is smeared down the profile. What is this? a) Abrasion b) Corrosion c) Spalling d) Scoring 121. In gearing system, it is the advance of the tooth in the face width divided by circular pitch. What do you call this? a) Face contact ratio b) Speed ratio c) Profile ratio d) Advance ratio 122. When the pitch line speed is above 8000 fpm, the teeth should be _____. a) Ground after hardening b) Should be cooled in air c) Should not be quenched after hardening` d) none of these 123. How do you call a spring material that is hard drawn (80 % reduction) but made up of high-grade steel? a) Music wire b) Oil tempered wire c) Song wire d) Chromium-silicon wire 124. It is a spring wire with good quality for impact loads and moderately high temperatures. What is this spring material? a) Hard drawn spring wire b) helical spring wire c) Chromium-silicon d) Helical tension wire 125. It is a type of coil spring where the helical coil is wrapped into a circle forming an annular ring. How do you call this spring? a) Volute spring b) Motor spring c) Hair spring d) Garter spring 126. It is a type of spring where thin flat strip wound up on itself as a plane spiral, usually anchored at the inside end. What do you call this spring? a) Volute spring b) Motor spring c) Hair spring d) Garter spring 127. What do you call a ratio of the length of the column and the radius of gyration of the cross-sectional area about the centroidal axis? a) Power factor b) Contact ratio d) Constant ratio d) Slenderness ratio 128. A screw that requires a positive torque to lower the load, or to loosen the screw if it has been turned tight against a resistance. How do you call this screw? a) Power screw b) Self screw c) Lock screw d) Self-locking screw 129. What is the other term used for Kennedy key? a) Tangential key b) Normal key c) Saddle key d) Rollpin key 130. Which of the following device used to measure the speed accurately? a) Dial gage b) Dial indicator c) Speedometer d) Tachometer

8

MACHINE DESIGN/SHOP PRACTICE 131. When the hole is smaller than the shaft, it will take pressure to put the parts together. The allowance is said to be negative and is termed as: a) Interference of metal b) Negative allowance c) Negative tolerance d) Negative fits 132. When two elastic bodies collide, which of the following laws can be used to solve for the resulting velocity? a) Avogadro’s law b) Conservation of momentum and conservation of energy c) Dalton’s law of partial pressure c) Conservation of energy 133. It is a science of motion that can be solved in terms of scalar or vector algebra. How do you cal this science? a) Kinematics b) Dynamics of machine c) Engineering mechanics d) Strength of materials 134. What is a screw fastener with a nut on it? a) Bolt b) Rivet c) Fastener d) Square screw 135. It is a type of bolt distinguished by a short portion of shank underneath the head, being square or finned or ribbed. What is this bolt? a) Coupling bolt b) Machine bolt c) Stud bolt d) Carriage bolt 136. Non-ferrous filler metal is melted into grooves or as fillet on the mother metal; the base metal is not melted. This is commonly used for joining iron based machine parts or in repair works of some materials. It is called: a) Spot welding b) Braze welding c) Brazing d) Gas welding 137. It is advised that in rubber belts applications/mountings, it should have an initial tension of: a) 18 to 24 lb/inch-ply b) 15 to 20 lb/inch-ply c) 12 to 15 lb/inch-ply 138. Normal stress relieving temperature for cast iron: o o o b) 400 to 500 F c) 300 to 550 F a) 200 to 350 F

d) 10 lb/inch-ply o

d) 450 to 550 F

139. A flexible coupling consists of essentially of two chain sprockets connected with short continuous length of roller or silent chains. a) Chain coupling b) Oldham coupling c) Flanged coupling d) Universal joint 140. A material of construction (only developed commercially in the late 1940’s concurrently with zirconium) offers the unique combination of wide ranging corrosion resistance, low density, and high strength. a) Titanium b) Tungsten c) Vanadium d) Molybdenum SET B 1. As one example, the ASME for riveted joints permits the design surface compressive stress to be about __________ higher than the design stress. a) 50 % b) 40 % c) 60 % d) 70 % 2. When tested in compression, ductile materials usually exhibit ________ characteristics up to the yield strength as they do when tested in tension. a) The same b) Less than c) More than d) Approximately the same 3. 4.

5. 6.

7. 8.

Helical gears mounted on non-parallel shafts are called a) Open gear b) Crossed helical gear c) Closed helical gear d) Herringbone For a symmetrical cross-sectional beam, what is the value of flexural stress when the vertical shear stress is at maximum? a) Infinity b) Maximum c) Zero d) Minimum Is the distance between the teeth measured on the pitch surface along a normal to the helix. a) Lead b) Lead angle c) Pitch d) Normal circular pitch The hardness of helical and herring bone teeth cut after heat treatment eill generally fall between the limits of a) 210 and 300 Brinell b) 147 to 300 Brinell c) 230 and 320 Brinell d) 220 and 320 Brinell The typical helix angle ranges form ____ to _____. o o o o o o b) 10 to 12 c) 14 to 20 a) 12 to 15 Is the advance of the tooth in the face width divided by circular pitch. a) Face contact ratio b) Speed ratio c) Profile ratio

o

o

d) 15 to 25

d) Advance ratio o

To eliminate fouling, let the minimum differences in tooth numbers between the internal gear and pinion, be ____ for 14.5 involute full-depth. a) 10 teeth b) 14 teeth c) 12 teeth d) 16 teeth 10. The loss per pair of spur, helical, or bevel gears in an ordinary train should no exceed ______. a) 4% b) 2% c) 6% d) 3% 9.

11. If the atoms which compose the molecules of a pure chemical substance are not all of the same kind, the substance is known as: a) Compound substance b) Elementary substance c) Pure substance d) Mixture substance 12. These non-destructive test methods employ high-frequency mechanical vibrational energy to detect and locate structural discontinuities or differences and to measure thickness of a variety of materials. How do you call these test methods? a) Ultrasonic test methods b) Radiographic test methods c) Eddy current nondestructive tests d) Microwave test methods 13. If the molecules or atoms of which any given material is composed are all exactly alike, the material is said to be as a: a) Compound substance b) Simple substance c) Mixture substance d) Pure substance 14. If the atoms which compose the molecules of any pure substances are all of the same kind, the substance is called as: a) An elementary substance b) A compound substance c) A pure substance d) A simple substance 15. The strength of non-ferrous alloys is maximum at room temperature while that of ferrous metal has a maximum strength at: o o o o b) 450 F c) 1200 F d) 350 F a) 400 F 16. When the chromium content is increased to about 11 percent in an iron-chromium alloy, the resulting material is generally classified as what material? a) Stainless steel b) Carbon Steel c) Wrought steel d) Cast Steel 17. How do you call those tests that determine the usefulness, serviceability, or quality of a part or material without limiting its usefulness? These tests are used in machinery maintenance to avoid costly unscheduled loss of service due to fatigue or wear; and they are used in manufacturing to ensure product quality and minimize costs.

9

MACHINE DESIGN/SHOP PRACTICE a) Nondestructive tests b) Destructive tests c) Hydro tests d) Penetrant tests 18. The lack of backlash in a spur gear design/operation may result to: a) Overloading b) Jamming c) Overheating d) Both a, b, & c 19. Splines are used when: a) The power to be transmitted is high b) The torque is high c) The speed is high d) Axial relative motion between shaft and hub is necessary 20. Which of the following contains chromium? a) SAE 2340 b) SAE 4230 21. Which of the following is not a heat treatment process? a) Sintering b) Annealing

c) SAE 5240

d) SAE 1230

c) Hardening

d) Tempering

22. An instrument used to analyse the compositions of metals: a) Spectrometer b) Radiometer c) Profilometer d) Ultimate analyser 23. Creep is the term used in referring to the: a) Elongation before yield point b) Maximum stress of brittle materials c) Fatigue limit of ductile materials d) Continuous increase in the strain, or deformation, of any material subjected to stress 24. The function of the clutch in the machine tools is: a) Lowering the drive speed b) To disconnect or connect the shaft at will the drive c) Alignment of drive shaft d) To insure that two shafts line up at high speed 25. Should two equal and opposite collinear forces is added to the forces already in equilibrium, which of the following statements is true? a) Unbalanced moment is maintained b) Equilibrium is maintained c) Equilibrium is distributed c) It creates an unbalanced situation 26. Also called as eccentricity loaded bearing: a) Full bearing b) Offset bearing c) Partial bearing 27. The moment of inertia of a rectangle whose base is “b” and height “h” about its base: a)

bh 3 4

b)

bh 3 12

c)

bh 3 24

d) Fitted bearing

d)

bh 3 3

28. Opposite directional forces equal in magnitude and parallel is called as: a) Non coplanar b) Couple c) Centro d) Coplanar 29. The hardness of helical and herring bone teeth cut after heat treatment eill generally fall between the limits of a) 210 and 300 Brinell b) 147 to 300 Brinell c) 230 and 320 Brinell d) 220 and 320 Brinell 30. The typical helix angle ranges form ____ to _____. o o o o b) 10 to 12 a) 12 to 15 31. Which of the following is a unit of energy? a) Ft-lb b) Hp 32. Steel containing large amounts of mild nickel and chromium: a) Carbon steel b) Alloy steel

o

c) 14 to 20

o

o

o

d) 15 to 25

c) Btu/hr

d) Watt

c) Stainless steel

d) Cast steel

33. Eccentricity loaded bearing is also called as: a) Hydrostatic bearing b) Split bearing c) Partial bearing d) Offset bearing 34. In the selection of wire rope, Lang lay means the wires and strands are twisted: a) In the same direction b) In any direction c) In opposite directions d) In along direction 35. Continuous stretching under load even if the stress is less than the yield point: a) Plasticity b) Creep c) Elasticity 36. The product of the mass and the linear velocity of a body: a) Angular impulse b) Angular momentum c) Linear impulse

d) Ductility d) Linear momentum

37. The length of the hub should not be made lesser than the face width of the gear. Hub lengths usually vary from 1.25D to 2D, where D is the shaft diameter. The reasonable diameter of steel hub should be: a) 2D b) 1.55D c) 1.8D d) 1.20D 38. It is the plane perpendicular to the axial plane and to the pitch plane. In gear the parallel axes, and the plane rotation coincide. a) Tangent plane b) Straight plane c) Transverse d) Reference plane 39. Type of bolt commonly used in the construction that is threaded at both ends. a) Stud bolt b) Hex bolt c) ACME thread bolt d) Square threaded bolt 40. The most known lubricants being utilized in whatever category of load and speed are oil, air, grease and dry lubricants like: a) Bronze b) Silicon c) Lead d) Graphite 41. Imaginary formed by the intersection of the flanks of a thread when extended is called ________ beyond the root. a) Sharp crest b) Root apex c) Sharp root d) Crest line 42. A hydrostatic bearing is one which: a) Lube oil is supplied under pressure b) There is no lube c) Lube oil is not pressurized d) Bearing is slightly loaded 43. An ideal herringbone gear helix angle is in the range of: o o o o o o o o b) 35 to 50 c) 25 to 30 d) 15 to 20 a) 30 to 45

10

MACHINE DESIGN/SHOP PRACTICE 44. A machine member which is used to connect shafts and to disconnect them at will: a) Coupling b) Clutch c) Collar d) Universal joint 45. Poisson’s ratio is the ratio of: a) Lateral stress to longitudinal stress b) Shear stress to shear strain c) Compressive stress to tensile stress d) Lateral strain to longitudinal strain 46. In a chain drive design for large speed reduction, it is preferable to use a double reduction of compound type of transmission instead of single two sprockets transmission. Drives should be so designed that the angle between two tight chain strand does not exceed: o o o o b) 55 c) 60 d) 90 a) 45 47. The product of the mass and the linear velocity of a body is called as: a) Linear impulse b) Linear momentum c) Couple d) Vector 48. Bearing surface that completely surrounds the journal is also called as: a) Offset bearing b) Centrally loaded bearing c) Full bearing 49. The ratio of the pitch diameter in inches to the number of teeth. a) Diametral pitch b) Circular pitch c) Module

d) Babbitt bearing d) English Module

50. Molybdenum-chromium-nickel steel designation: a) SAE 48xx b) SAE 43xx c) SAE 56xx d) SAE46xx 51. Arc of the pitch circle through which a tooth travels from the point of contact with the mating tooth to the pitch point of a gear. a) Arc of recess b) Arc of action c) Arc of approach d) Arc of relief 52. Which of the following is not pertaining to the joining of metals? a) Welding b) Soldering 53. Killed steel is always associated with: a) Silicon b) Manganese

c) Casting

d) Brazing

c) Phosphorous

d) Sulfur

54. What is the usual ratio of water to soluble oil used as cutting fluid? a) 50 % water to 50 % oil b) 2 water to 1 oil c) 3 water to 1 oil 55. Which of the following is not pertaining to the joining of metals? a) Welding b) Soldering c) Casting 56. Killed steel is always associated with: a) Silicon b) Manganese c) Phosphorous 57. What is the usual ratio of water to soluble oil used as cutting fluid? a) 50 % water to 50 % oil b) 2 water to 1 oil c) 3 water to 1 oil

d) 4 to 80 water to 1 oil d) Brazing

d) Sulfur d) 4 to 80 water to 1 oil

58. Statement that a given body is in static equilibrium means that the body cannot: a) Have any type of motion b) Be acted upon by more than one force c) Undergo any displacement d) Have any acceleration 59. Ordinary steel begins to loose strength and elasticity significantly at about: o o o o b) 800 to 900 F c) 750 to 850 F d) 600 to 700 F a) 900 to 1000 F 60. Clearance to a new boiler installation to the existing or old plant building should follow a minimum clearance of ________ between top of the boiler proper and the ceiling as stated in the PSME Code. a) 2000 mm (max) b) 1000 mm (max) c) 2130 mm (max) d) 2150 mm (max) 61. For a high corrosion resistant stainless steel, what minimum chromium content is required? a) 8 % b) 4.3 % c) 1.1 % d) 5.8 % 62. Name the type of chuck commonly used for holding workpiece in a lathe operation. Example: 3-jaw universal chuck, 4-jaw independent chuck. a) Magnetic jaw chuck b) 2-jaw independent chuck c) 8-jaw universal d) Combination 63. V-belt operate efficiently at speed of about: a) 4500 fpm b) 4400 fpm c) 4200 fpm d) 3600 fpm 64. What type of gear is used for high speed operation? a) Helical b) Spur c) Bevel d) Worm 65. In a pair of gears, it is the plane perpendicular to the axial plane and tangent to the pitch surface. a) Pitch b) Pitch plane c) Pitch circle d) Pitch point 66. Normal stress relieving temperature for cast iron: o o o b) 400 to 500 F c) 300 to 550 F a) 200 to 350 F 67. Most effective alloying element for reducing brittleness of steel at very low temperature: a) Manganese b) Molybdenum c) Silicon 68. Deals only with the motion of bodies without reference to the forces that cause them: a) Dynamics b) Kinetics c) Statics 69. The property that characterizes a material ability to be drawn onto a wire: a) Ductility b) Thermal conductivity c) Tensile strength

o

d) 450 to 550 F d) Nickel

d) Kinematics d) Endurance limit

70. One of the causes of spur gear tooth breakage is the unbalanced load on one end of the tooth that results in higher stresses than when the load is evenly distributed. To minimize this problem, the face width “b” should not be greater than the thickness (or pitch) of the tooth. In the absence of test values, the following can be a guide: b) 2pd < b < 4 pd c) 2.5pd < b < 4pd d) 2pc < b < 4 pc a) 2.5pc < b < 4pc 71. The three moment equation may be used to analyse: a) Tapered column b) Continuous beam c) Composite beam d) Axially end loaded beam

11

MACHINE DESIGN/SHOP PRACTICE 72. What is the common shop practice ti prevent solder from running away from surface to be joined? a) Surround the work with clay b) Introduce around the work rolled wet cloth c) Put asbestos sheathing around the work d) All of these 73. Non-ferrous filler metal is melted into grooves or as fillet on the mother metal; the base metal is not melted. This is commonly used for joining iron based machine parts or in repair works of some materials. It is called: a) Spot welding b) Braze welding c) Brazing d) Gas welding 74. It is advised that in rubber belts applications/mountings, it should have an initial tension of: a) 18 to 24 lb/inch-ply b) 15 to 20 lb/inch-ply c) 12 to 15 lb/inch-ply d) 10 lb/inch-ply 75. Hypoid gear is a special type of gear like: a) Worm gear b) Spur gear c) Herringbone gear d) Bevel gear 76. The considered maximum safe center distance of sprockets because very long center distance causes catenary tension in the chain. a) 70 pitches b) 80 pitches c) 60 pitches d) 50 pitches 77. Cold working of steel plates make the metal: a) Tougher b) More ductile c) Harder d) More malleable 78. Recommended best cutting angle of drill for work on steel or cast iron is: a) 48 degree b) 63 degrees c) 59 degrees d) 50 degrees 79. In shear pin or breaking pin design, we may use the data experienced by link belt from 1/8 inch to 1 inch pins and the breaking stress is: a) 40 ksi b) 55 ksi c) 50 ksi d) 48 ksi 80. All are associated with the grade of steel except: a) SAE 43xx b) SAE 13xx c) SAE 10xx 81. A property of material that relates the lateral strain to the longitudinal strain: a) Stress b) Strain c) Poisson’s ratio

d) SAE 74xx d) Strength

82. The maximum stress to which a material may be subjected before failure occurs. a) Ultimate strength b) Ultimate stress c) Endurance limit d) Tensile stress 83. The smallest area at the point of rupture of a tensile specimen divided by the original area is called: a) Percentage elongation b) Izod test c) Charpy test d) Percentage reduction of area 84. The product of the resultant of all forces acting on a body and the time that the resultant acts: a) Angular impulse b) Angular momentum c) Linear Impulse 85. Which of the following is not a structural class of steel? a) Low carbon steel b) Tool and die steel c) High chrome alloy steel

d) High strength low allow steel

86. Poisson’s ratio is the ratio of which of the following? a) Shear strain to compressive strain c) Lateral strain to longitudinal strain 87. Metal that assists lubrication or lubrication in itself: a) Zinc b) Antimony

d) Lead

d) Linear momentum

b) Elastic limit to compressive strain d) Elastic limit to proportional limit c) Babbit

88. A mechanism that usually do the indexing in a machine tool: a) Universal chuck b) Slotter c) Dividing head d) Indexing 89. It equalizes the energy exerted and the work done, thus, preventing excessive or sudden changes of speed: a) Flywheel b) Balance wheel c) Flywheel pulley d) All of these 90. It is a spring wire with good quality for impact loads and moderately high temperatures. What is this spring material? a) Hard drawn spring wire b) helical spring wire c) Chromium-silicon d) Helical tension wire 91. How do you call a load that is applied transversely to longitudinal axis of member? a) Combined loads b) Concentrated load c) Bending load d) Distributed load

12

MACHINE DESIGN/SHOP PRACTICE

JCSF ENGINEERING REVIEW CENTER 2nd Floor Santos‐Causing Building, National Highway  Halang, City of Calamba, Laguna

MACHINE DESIGN AND SHOP PRACTICE (Refreshers Trivia # 3) Prepared by: Jose R. Francisco, PME September 2012 MULTIPLE CHOICE QUESTIONS Select the best answer from each of the following questions. On the answer sheet provided, shade the box that corresponds to your choice. Strictly no erasures allowed. 1.

What is the stress area of a 1-inch diameter bolt that has a TPI (Threads per inch) of 8? 2 2 2 b) 0.626 in c) 0.443 in a) 0.565 in Solution: A = π [D − 0.9743p]2 : → p = 1 : s 4

2.

TPI

→ A s = 0.606in 2

A simple band brake, installed on a 500mm brake drum, is used to absorb a torque of 250 N-m. If the coefficient of friction and the contact angle between the band and drum are 0.2 and 180º, respectively, and that the length of the brake arm is twice the drum diameter, determine the minimum braking force applied at the free end of the brake arm. a) 721.5 N b) 752.1 N c) 275.1 N d) 572.1 N

F2 (a ) Solution: F1 = e fθ = 1.874 : → F : a = D : → L = 2D b min =

DA D = B : sin α sin β

1 2 .5 = : β = 58.77 o : sin 20 o sin β

F1 =e F

⎡ ⎢ fθ ⎢ ⎢ sin 1 β 2 ⎣⎢

⎤ ⎥ ⎥ ⎥ ⎦⎥

= 15 . 044 :

T =

T =

( F1 − F2 ) D : F1 = 268 . 5 N 2

A shaft is simultaneously loaded with a torque of 900 N-m and a bending load of 4000N applied at the center of its 500mm span. Considering a maximum shear design stress of 60 MPa, determine the shaft diameter. a) 38.44 mm b) 34.83 mm c) 44.38 mm d) 84.33 mm → Te = T 2 + M 2

→

16Te πD 3

= Ssd

→ D = 44.38mm

A 20-kW motor, running at 1200 rpm, drives a 400 mm diameter pulley at a belt tension ratio of 2.4. If the belt’s tight side tension is only 1200 N, determine the transmission efficiency. a) 87.97 % b) 84.58 % c) 85.66 % d) 86.55 %

Solution: η =

8.

→ FR = Ft2 + Fr2 = 580.2 N

θ = α + β = 78.77 deg .

Power x 9 . 549 x 10 6 : n

Solution: T = 900,000 N − mm : → M = FL = 500,000 N − mm 4 7.

→ Fr = Ft tan φ = 198.6 N :

A V-belt drive uses a 152.4 mm sheave with a groove angle of 36º. The sheave is coupled to a 2 kW motor running at 1000 rpm. Considering a belt coefficient of friction of 0.3 and a contact angle of 160º, determine the maximum tension on the V-belt. a) 586.7 N b) 752.8 N c) 268.5 N d) 685.2 N Solution:

6.

→ Ft = 546.7 N

Two bevel gears at a gear ratio of 2.5:1 are used for a certain drive. If the pinion has a cone angle of 20º, determine the shaft angle of the gears. a) 75.85º b) 69.23º c) 84.23º d) 78.77º Solution:

5.

2T F2 D = = = 572.1N 2 2(1.874 − 1)

Calculate the resultant bending load on a shaft that carries a 200mm-diameter, 20º full depth pinion. The pinion transmits 10 kW at 1750 rpm. a) 258.0 N b) 685.0 N c) 850.2 N d) 580.2 N

⎡ 10 ⎤ 2⎢ x 9.549 x10 6 ⎥ 2 T 1750 ⎣ ⎦: Solution: Ft = = D 200 4.

→ Fb min

L

F2

3.

2

d) 0.606 in

Poutput Pinput

1200 ⎞ ⎛ 1200 π ⎞ ⎛ 0.40 ⎞ ⎛ ⎛ π n ⎞⎛ D ⎞ Tout (π n ) ⎛ π n ⎞ ⎛ D ⎞ F ⎟ ⎟ ⎜1200 − ⎟⎜ ⎟ ⎜ ⎟ (F1 − F2 ) ⎜ ⎟ ⎜ ⎟ net ⎜ ⎜ 30 ⎠ ⎝ 2 ⎠ 30 ⎠ ⎝ 2 ⎠ 30 ⎠ ⎝ 2 ⎠ ⎝ 2.4 ⎠ 30 = 0.8797 =⎝ =⎝ = =⎝ Pinput Pinput Pinput 20 000

A cylindrical vessel has an inside diameter of 40 inches, is subjected to a pressure of 2000 psi, and is constructed with a joint efficiency of 90%. Find the thickness if the allowable stress of the steel plate used is 10,000 psi. a) 4.44 in b) 5.07 in. c) 6.58 in. d) 8.56 in

S Solution: S = p D = y = S t d 2tEj

N

→ t = 4.44 in.

but

t > 0.1 D

→ thick − walled

1

MACHINE DESIGN/SHOP PRACTICE

t= 9.

D ⎡ S+ p ⎤ − 1⎥ ⎢ 2 ⎢⎣ S − p ⎥⎦

→ S = 0.9x10,000 = 9000 : → t = 5.07in.

Find the maximum permissible concentrated bending load that may be carried by a simply-supported shaft of 2-ft span of 2-in. diameter if the allowable flexural stress is 6,000 psi. a) 854.7 lb b) 485.7 lb c) 587.4 lb d) 785.4 lb Solution: Bending moment is maximum if F is applied at mid span.

σ=

Mc 32M = I πD 3

→ M=

FL 4

32(F)(24) = 6000 4π(2 3 )

→

→ F = 785.4lb.

10. A bar of rectangular section is made of AISI C1020 steel (Su = 65,000 psi), and is subjected to a tensile load of 8 tons. If the width of the bar is 1.5 times the thickness, find the bar dimensions if the factor of utilization is 0.25 based upon the ultimate strength. a) 0.5” x 0.75” b) 1” x 1.5” c) 1.5” x 2.25” d) 0.81” x 1.22” Solution: Factor of Utilization =

1 Factor of Safety

s=

S F 8 x 2000 = u = ( U.FxS u ) : = 0.25 x 65000 : → b = 0.81in. N 1 .5 b 2 1 .5 b 2

and b x h = 0.81” x 1.22” 11. A low carbon steel sheet 3/8 in. thick, lined with aluminum 1/8 in. thick, is used to form a connecting rod. Steel has a modulus of elasticity of 30 x 10 6 psi, while aluminum of 10.3 x 10 psi. If the aluminum has a tensile stress of 10,000 psi, what is the corresponding stress of the steel sheet? a) 12,961 psi b) 96,122 psi c) 29,126 psi d) 26,191 psi Solution: σ = E ε: With constant strain ε, σAL/EAL = σST/EST.

6

Thus, σST = (30/10.3) x (10,000) = 29,126 psi.

12. A 25 mm square threaded screw (20 mm root diameter, pitch = 5 mm), is 380 mm long between the nut and the collar. The axial load is 25,000 N and the torque in the screw between the nut and the collar, is 110 N-m. Using end fixity factor of unity and neglecting the threads, determine the factor of safety if steel with a yield point in tension of 345 Mpa is used. Consider the modulus of elasticity for steel to be 200 GPa. a) 2.41 b) 2.04 c) 1.34 d) 1.96 SR =

Solution:

L e n e L n e L 380(4) = = = = 76