1
PRIME REVIEW CENTER
by:
ENGR. HAROLD B. BORJA, RME
REFRESHER
MD Refresher 1
2/20/2016
2
• 1-60 MD Problems
• 61-100 MD Elements
February 20, 2016
by
ENGR. HAROLD B. BORJA, RME
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1
A square thread power screw has a
pitch diameter of 1.5 and a lead of 1 in.
Neglecting collar friction, determine the
coefficient of friction for threads if
screw efficiency is 63.62%.
a. 0.113 b. 0.121 c. 0.146 d. 0.151
REFRESHER 1
MACHINE DESIGN
2/20/2016
3
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SOLUTION:
𝐿𝑒𝑎𝑑
tan 𝑥 =
=
𝜋𝐷𝑚
4
1
𝜋 1.5
= 0.2122
tan 𝑥 1 − 𝑓 tan 𝑥
𝑒=
tan 𝑥 + 𝑓
0.2122 1 − 0.2122𝑓
0.6362 =
0.2122 + 𝑓
𝒇 = 𝟎. 𝟏𝟏𝟑
REFRESHER 1
MACHINE DESIGN
2/20/2016
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2
The total torque required to turn the
power screw is 50 N.m. If the linear
speed of screw is 7 fpm and lead of 8
mm, find the horsepower input of the
power screw.
a. 2.86 hp
b. 1.84 hp
c. 2.14 hp
d. 2.38 hp
REFRESHER 1
MACHINE DESIGN
2/20/2016
5
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6
SOLUTION:
𝑣
𝑃 = 2𝜋𝑇𝑁 = 2𝜋𝑇
𝐿𝑒𝑎𝑑
2𝜋 50
7
𝑃=
746 0.008 3.281 60
𝑷 = 𝟏. 𝟖𝟕 𝒉𝒑
REFRESHER 1
MACHINE DESIGN
2/20/2016
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3
Compute the working strength of 1” bolt
which is screwed up tightly in a packed
joint when the allowable working stress
is 13,000 psi.
a. 3,600 lb
b. 3,950 lb
c. 3,900 lb
d. 3,800 lb
REFRESHER 1
MACHINE DESIGN
2/20/2016
7
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SOLUTION:
𝑊 = 𝑆𝑡 0.55𝑑 2 − 0.25𝑑
𝑊 = 13,000 0.55 1
2
− 0.25 1
𝑾 = 𝟑, 𝟗𝟎𝟎 𝒍𝒃
3
REFRESHER 1
MACHINE DESIGN
2/20/2016
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4
If the pitch of a screw is 2/9, find the
thread per inch.
a. 0.34 b. 4.5 c. 5.4 d. 17
SOLUTION:
1
1
𝑇𝑃𝐼 = =
= 𝟒. 𝟓
𝑝 2 9
REFRESHER 1
MACHINE DESIGN
2/20/2016
9
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A pulley delivers a torque of 930 N.m thru
a shaft of 50.8 mm diameter. The width of
the key used is 1 cm. The shaft and key
are made of same material. The allowable
shearing stress of the shaft is 60 MPa.
Determine the length of the key.
a. 50 mm b. 55 mm c. 58 mm d. 61 mm
REFRESHER 1
MACHINE DESIGN
2/20/2016
10
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11
SOLUTION:
𝐹
2𝑇
𝐿=
=
𝑤𝑆𝑠𝑘𝑒𝑦 𝐷𝑤𝑆𝑠𝑘𝑒𝑦
2 930 1000
𝐿=
0.0508 0.01 60𝑥106
𝑳 = 𝟔𝟏 𝒎𝒎
REFRESHER 1
MACHINE DESIGN
2/20/2016
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12
An eye bolt is lifting 500 lb weight. The
Su = 70 ksi and Sy = 58 ksi. What is the
stress area of the bolt?
a. 0.009 in2
c. 0.1388 in2
REFRESHER 1
b. 0.026 in2
d. 0.1276 in2
MACHINE DESIGN
2/20/2016
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SOLUTION:
3/2
𝑆𝑦 𝐴𝑠
𝐹𝑒 =
6
6𝐹𝑒
𝐴=
𝑆𝑦
2/3
6 500
𝐴=
58,000
REFRESHER 1
2/3
𝟐
= 𝟎. 𝟏𝟑𝟖𝟖 𝒊𝒏
MACHINE DESIGN
2/20/2016
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A keyed sprocket delivers a torque of 778.8
N.m thru the shaft of 54 mm OD. The key
thickness is 1.5875 cm and the width is 1.11
cm. Compute the length of the same key. The
permissible stress value is 60 MPa for shear
and 90 MPa for tension.
a. 39.12 cm
b. 4.82 cm
c. 52.22 cm
d. 4.32 cm
REFRESHER 1
MACHINE DESIGN
2/20/2016
14
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SOLUTION:
𝐹
2𝑇
𝑆𝑠 =
=
𝑤𝐿 𝐷𝑤𝐿
𝑇𝐷
𝐿=
2𝑤𝑆𝑠
2 778.8𝑁 ∙ 𝑚
𝐿=
0.054𝑚 0.0111𝑚 60𝑥106 𝑁/𝑚2
𝐿 = 0.0433 𝑚 = 𝟒. 𝟑𝟑 𝒄𝒎
REFRESHER 1
MACHINE DESIGN
2/20/2016
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A horizontal beam 20 ft long is subjected to
a load 1000 lb located at its center. The
dimension of the beam is 3 x 6 inches,
respectively and its unit weight is 50 lb/ft.
Determine the radius of gyration of the
beam.
a. 1 in
b. 2 in
c. 1.732 in
d. 3.512 in
REFRESHER 1
MACHINE DESIGN
2/20/2016
16
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SOLUTION:
𝑏ℎ3 3 6 3
4
𝐼=
=
= 54 𝑖𝑛
12
12
𝐾=
8
REFRESHER 1
𝐼
=
𝐴
54
= 𝟏. 𝟕𝟑𝟐 𝒊𝒏
3 6
MACHINE DESIGN
2/20/2016
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The stress area is 0.763 in2, if material
used is carbon steel, determine the
applied load on the bolt.
a. 3407.14 lb b. 3846.71 lb
c. 4025.86 lb d. 3102.74 lb
9
REFRESHER 1
MACHINE DESIGN
2/20/2016
18
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SOLUTION:
𝐹𝑎 = 𝐶 𝐴𝑟
1.418
𝐹𝑎 = 5,000 0.763
1.418
𝐹𝑎 = 𝟑, 𝟒𝟎𝟕. 𝟏𝟒 𝒍𝒃
9
REFRESHER 1
MACHINE DESIGN
2/20/2016
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10
A 1.5 MTon hoist is to be installed in an I-beam
mounted on a truck platform, to lift loads. The Ibeam is framed horizontally, cantilevered, with
overhang of 1.5 m beyond the cantilever
fulcrum. Determine the section modulus, in m3,
of the beam if allowable stress is 100 MPa.
a. 0.0002207
b. 0.0007022
c. 0.002007
d. 12.24
REFRESHER 1
MACHINE DESIGN
2/20/2016
20
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SOLUTION:
𝑀𝑐
𝑀
𝑀
𝑆𝑓 =
=
=
𝐼
𝐼/𝑐 𝑍
𝑀 𝐹𝐿 1.5 1000 1.5 9.81 𝑁 ∙ 𝑚
𝑍= =
=
100𝑥106 𝑁
𝑆𝑓
𝑍
𝑚2
𝒁 = 𝟎. 𝟎𝟎𝟎𝟐𝟐𝟎𝟕
REFRESHER 1
MACHINE DESIGN
2/20/2016
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The cutting speed of a tool passing thru
2.5 in diameter material at 200 rpm.
a. 110 fpm
b. 140 fpm
c. 115 fpm
d. 131 fpm
SOLUTION:
2.5
𝑉 = 𝜋𝐷𝑁 = 𝜋
12
REFRESHER 1
200 = 𝟏𝟑𝟎. 𝟗 𝒇𝒑𝒎
MACHINE DESIGN
2/20/2016
22
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The shaft is subjected to a steady load
40,000 lb at a shear stress of 12,000 psi.
Compute the diameter of the said shaft
in inches.
a. 3 in
b. 2 in
c. 2.5 in
d. 1.5 in
REFRESHER 1
MACHINE DESIGN
2/20/2016
23
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12
24
SOLUTION:
8𝐹𝐷
8𝐹
𝑆𝑠 =
=
3
𝜋𝐷
𝜋𝐷2
8 40,000
12,000 =
𝜋𝐷2
𝐷 = 2.91 𝑖𝑛
𝑺𝒂𝒚 𝟑 𝒊𝒏
REFRESHER 1
MACHINE DESIGN
2/20/2016
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13
Determine the bursting steam pressure
of a steel shell with diameter of 12 in
and made of ¼ in steel plate. The joint
efficiency is at 75% and the tensile
strength is 55 ksi.
a. 3,440 psi b. 3,430 psi
c. 3,437 psi d. 3,427 psi
REFRESHER 1
MACHINE DESIGN
2/20/2016
25
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SOLUTION:
4𝑡𝑒𝑆𝑡 4 0.25 0.75 55,000
𝑝=
=
𝐷
12
𝑝 = 3,437.5 𝑝𝑠𝑖
𝐵𝑢𝑟𝑠𝑡𝑖𝑛𝑔 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 > 𝟑, 𝟒𝟑𝟕. 𝟓 𝒑𝒔𝒊
13
REFRESHER 1
MACHINE DESIGN
2/20/2016
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How long a wire is needed to make a
helical spring having a mean coil
diameter of 0.820 in if there are five coils
in the spring?
a. 4.52 in
b. 7.67 in
c. 6.66 in
d. 12.88 in
REFRESHER 1
MACHINE DESIGN
2/20/2016
27
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SOLUTION:
𝐿 = 𝜋𝐷𝑛 = 𝜋 0.820 5
𝐿 = 𝟏𝟐. 𝟖𝟖 𝒊𝒏
14
REFRESHER 1
MACHINE DESIGN
2/20/2016
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A worm-gear set has a single start worm.
The worm has a pitch diameter of 2 in. The
gear has 60 teeth with a diametral pitch of 6.
The input shaft is driven at 1,750 rpm from a
5 hp motor. The pressure angle is 20o. Find
the pitch diameter of the gear.
a. 6 in
REFRESHER 1
b. 10 in
c. 8 in
d. 12 in
MACHINE DESIGN
2/20/2016
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SOLUTION:
𝑁𝑔 60
𝐷𝑝 =
=
= 𝟏𝟎 𝒊𝒏
𝑃𝑑
6
15
REFRESHER 1
MACHINE DESIGN
2/20/2016
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A 6.35 mm steel shaft transmit 3.39 N.m
of torque; the effective length of the
shaft is 304.8 mm. The modulus of
elasticity in shear is 83 GPa. Find the
angular deflection in degrees.
a. 3.28o b. 9.31o c. 6.72o d. 4.48o
REFRESHER 1
MACHINE DESIGN
2/20/2016
31
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SOLUTION:
32𝑇𝐿 32 3,390 304.8
𝜃=
=
𝜋𝑑 4 𝐺 𝜋 6.35 4 83,000
𝒐
𝜃 = 0.07799 𝑟𝑎𝑑 = 𝟒. 𝟒𝟕
16
REFRESHER 1
MACHINE DESIGN
2/20/2016
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17
A punch punches a 1-in diameter hole in a steel
plate ¾ inch thick every 10 sec. The actual
punching takes 1 sec. The ultimate shear strength
of the plate is 60,000 psi. The flywheel of the
punch press has a mass moment of inertia of 500
in-lb-sec2 and rotates at a mean speed of 150 rpm.
What is the horsepower required for the punch
operation?
a. 9.04 hp b. 8.03 hp c. 7.04 hp d. 10.04 hp
REFRESHER 1
MACHINE DESIGN
2/20/2016
33
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SOLUTION:
∆𝐾𝐸 𝑆𝑢 𝜋𝐷𝑡 2
𝑃=
=
𝑡𝑖𝑚𝑒
2𝑡𝑖𝑚𝑒
𝑙𝑏
𝜋 60,000 2 1𝑖𝑛 0.75𝑖𝑛
𝑖𝑛
𝑃=
𝑓𝑡 ∙ 𝑙𝑏/𝑠
12𝑖𝑛
2 1𝑠
550
1𝑓𝑡
1ℎ𝑝
2
𝑃 = 𝟖. 𝟎𝟑 𝒉𝒑
REFRESHER 1
MACHINE DESIGN
2/20/2016
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Find the tooth thickness of a 20o full
depth involute tooth having a diametral
pitch of 4.
a. 9.97 mm
b. 7.99 mm
c. 3.93 mm
d. 3.97 mm
18
REFRESHER 1
MACHINE DESIGN
2/20/2016
35
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SOLUTION:
1.5708 1.5708
𝑡=
=
𝑃𝑑
4
𝑡 = 0.3927 𝑖𝑛 = 𝟗. 𝟗𝟕 𝒎𝒎
18
REFRESHER 1
MACHINE DESIGN
2/20/2016
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All four compression coil spring
support one load of 70 kg. All four
springs are arranged in parallel and
rated the same at 0.609 kg/min.
Compute the deflection in mm.
a. 64 mm
b. 178 mm
c. 147 mm
d. 287 mm
REFRESHER 1
MACHINE DESIGN
2/20/2016
37
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38
SOLUTION:
𝐹𝑜𝑟 𝑃𝑎𝑟𝑎𝑙𝑙𝑒𝑙 𝑆𝑝𝑟𝑖𝑛𝑔𝑠,
𝑦1 = 𝑦2 = 𝑦3 = 𝑦4 = 𝑦
𝑇ℎ𝑒𝑛,
𝐹/4 700/4
𝑦=
=
= 𝟐𝟖𝟕. 𝟑𝟔 𝒎𝒎
𝑘
0.609
REFRESHER 1
MACHINE DESIGN
2/20/2016
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A 1,200 mm cast iron pulley is fastened to a
112.5 mm shaft by means of a 28.13 mm
square key 175 mm long. What force acting
at the pulley rim will shear the key if shear
stress of the key is 20.67 kg/mm2?
a. 9,538 kg
c. 8,593 kg
REFRESHER 1
b.
d.
5,839 kg
3,659 kg
MACHINE DESIGN
2/20/2016
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20
40
SOLUTION:
𝑇𝑝𝑢𝑙𝑙𝑒𝑦 = 𝑇𝑘𝑒𝑦
𝐹𝑝 𝑟𝑝 = 𝐹𝑘 𝑟𝑠
𝐷𝑝
𝐷𝑠
𝐹𝑝
= 𝑤𝐿𝑆𝑠
2
2
1200
𝐹𝑝
= 28.13 175 20.67
2
𝐹𝑝𝑢𝑙𝑙𝑒𝑦 = 𝟗, 𝟓𝟑𝟗. 𝟑𝟕 𝒌𝒈
REFRESHER 1
MACHINE DESIGN
112.5
2
2/20/2016
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What should be the diameter of pulley in
inches with a belt speed of 4,500 fpm and the
motor running at 1,760 rpm?
a. 9.76 in b. 10 in c. 7.76 in d. 8.76 in
SOLUTION:
𝑓𝑡 12 𝑖𝑛
4,500
𝑉
𝑚𝑖𝑛 1 𝑓𝑡
𝐷=
=
= 𝟗. 𝟕𝟔 𝒊𝒏
𝜋𝑁
𝜋 1,760 𝑟𝑝𝑚
REFRESHER 1
MACHINE DESIGN
2/20/2016
41
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Compute for the pitch angle of a bevel gear
given the pinion’s number of teeth of 14
teeth and 42 teeth on the gear.
a. 18.4o b. 28.4o
c. 33.4o d. 38.4o
SOLUTION:
𝑇
14
𝑃𝑖𝑡𝑐ℎ 𝑎𝑛𝑔𝑙𝑒 = 𝑡𝑎𝑛
−1 𝑝
𝑃𝑖𝑡𝑐ℎ 𝑎𝑛𝑔𝑙𝑒 = 𝟏𝟖. 𝟒𝒐
REFRESHER 1
𝑇𝑔
= 𝑡𝑎𝑛−1
42
MACHINE DESIGN
2/20/2016
42
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The tooth thickness of a gear is 0.5 in and its
circular pitch is 1.0 in. Calculate the
dedendum of the gear.
a. 0.3183 b. 1.250 c. 0.3979 d. 0.1114
SOLUTION:
1.25 1.25𝑃
𝐷𝑒𝑑𝑒𝑛𝑑𝑢𝑚, 𝑑 =
𝑃𝑑
=
𝑐
𝜋
1.25 1 𝑖𝑛
𝑑=
= 𝟎. 𝟑𝟗𝟕𝟗 𝒊𝒏
𝜋
REFRESHER 1
MACHINE DESIGN
23
2/20/2016
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An 8 in nominal diameter journal bearing is
designed for 140o optimum when bearing
length is 9 in, speed is 1,800 rpm and total
load is 20,000 lb. Calculate the frictional
horsepower loss when this journal operates
under the coefficient of friction of 0.002.
a. 4.56 hp b. 10.2 hp c. 5.64 hp d. 15.6 hp
REFRESHER 1
MACHINE DESIGN
2/20/2016
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SOLUTION:
𝑃𝐿𝑜𝑠𝑠 = 𝑓𝐹𝑣 = 𝑓𝐹 𝜋𝐷𝑁
𝑃𝐿𝑜𝑠𝑠
𝑃𝐿𝑜𝑠𝑠
8
0.002 20,000 𝜋
12
=
33,000
= 𝟒. 𝟓𝟔 𝒉𝒑
1,800
24
REFRESHER 1
MACHINE DESIGN
2/20/2016
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25
A double-ply leather belt transmits 10 hp
from a motor with a pulley 8” in diameter,
running at 1,700 rpm, to a 24” diameter
pulley. The difference in tension may be
taken as 20 lb/in of belt width. Belt thickness
is 0.2”. Calculate the width of belt.
a. use 3” belt
b. use 5” belt
c. use 4” belt
d. use 6” belt
REFRESHER 1
MACHINE DESIGN
2/20/2016
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47
SOLUTION:
33,000𝑃
𝐷
𝑇=
= 𝐹1 − 𝐹2
2𝜋𝑁
2
33,000𝑃
33,000 10
𝐹1 − 𝐹2 =
=
= 92.684 𝑙𝑏
8
𝜋𝐷𝑁
𝜋
1,700
12
1 𝑖𝑛
1 𝑖𝑛
𝑊𝑖𝑑𝑡ℎ = 𝐹1 − 𝐹2
= 92.684 𝑙𝑏
20 𝑙𝑏
20 𝑙𝑏
𝑊𝑖𝑑𝑡ℎ = 4.63 𝑖𝑛 𝑜𝑟 𝑺𝒂𝒚 𝟓 𝒊𝒏 𝒃𝒆𝒍𝒕
REFRESHER 1
MACHINE DESIGN
2/20/2016
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What is the necessary thickness of the
cylinder wall of an internal combustion
engine chamber when the pressure in the
cylinder is 400 psi? The cylinder diameter in
the engine is 3.75” and maximum allowable
stress maybe taken as 2,000 psi.
a. 0.250 in
b. 0.500 in
c. 0.421 in
d. 0.625 in
REFRESHER 1
MACHINE DESIGN
2/20/2016
48
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49
SOLUTION:
𝐷
𝑡=
2
3.75
𝑡=
2
𝑆𝑡 + 𝑃
−1
𝑆𝑡 − 𝑃
2,000 + 400
−1
2,000 − 400
𝑡 = 𝟎. 𝟒𝟐𝟏 𝒊𝒏
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
27
50
What is pressure is required for punching a
1 by 2 inch rectangular hole in ¼ inch thick
brass?
a. 15 tons b. 32.5 tons c. 20 tons d. 40 tons
SOLUTION:
1
𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒 = 𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟 𝑡 65
3
1
1
𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒 = 2 1 + 2 2
65 = 𝟑𝟐. 𝟓 𝒕𝒐𝒏𝒔
3
4
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
28
A pinion and gear set is carefully out in a 20o
full depth design. The 16-tooth steel pinion and
72-tooth cast iron gear transmit 50 kW power
when the pinion turns 1,400 rpm. The face
width is 90 mm and the module is 8. Find the
center distance between pinion and gear.
a. 225 mm
c. 275 mm
REFRESHER 1
b.
d.
987 mm
352 mm
MACHINE DESIGN
2/20/2016
51
M
E
B
o
a
r
d
52
SOLUTION:
𝑇2 + 𝑇1
𝑚 𝑇2 + 𝑇1
𝐶=
=
2𝑃𝑑
2
8 72 + 16
𝐶=
= 𝟑𝟓𝟐 𝒎𝒎
2
28
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
29
A V-belt is to transmit 50 hp to a NH3
compressor. The sheave is 203.2 mm in
diameter and turns at 1,150 rpm, while the
larger sheave turns at 400 rpm. The service
factor may be taken as 1.5 and the center
distance is equal to the diameter of the larger
sheave. Determine the length of belt.
a. 67 in
REFRESHER 1
b. 87 in
c. 77 in
d. 97 in
MACHINE DESIGN
2/20/2016
53
M
E
B
o
a
r
d
29
54
SOLUTION:
𝐷1 = 203.2 𝑚𝑚 = 8 𝑖𝑛
𝑁1
1,150
𝐷2 = 𝐷1
=8
= 23 𝑖𝑛
𝑁2
400
𝐶 = 𝐷2 = 23 𝑖𝑛
𝜋
𝐷2 − 𝐷1 2
𝐿 = 2𝐶 + 𝐷2 + 𝐷1 +
2
4𝐶
𝜋
23 − 8 2
𝐿 = 2 23 + 23 + 8 +
= 𝟗𝟕. 𝟏𝟒 𝒊𝒏
2
4 23
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
30
A V-belt is to transmit 50 hp to a NH3 compressor.
The sheave is 203.2 mm in diameter and turns at
1,150 rpm, while the larger sheave turns at 400
rpm. The service factor may be taken as 1.5 and
the center distance is equal to the diameter of the
larger sheave. Determine the number of belts if the
corrected Hp per belt is 5.96.
a. use 10 belts
b. use 13 belts
c. use 11 belts
d. use 12 belts
REFRESHER 1
MACHINE DESIGN
2/20/2016
55
M
E
B
o
a
r
d
30
56
SOLUTION:
𝐷𝑒𝑠𝑖𝑔𝑛 𝐻𝑃
𝑁𝑜. 𝑜𝑓 𝑏𝑒𝑙𝑡𝑠 =
𝐶𝑜𝑟𝑟𝑒𝑐𝑡𝑒𝑑 𝑅𝑎𝑡𝑒𝑑 𝐻𝑃
50 1.5
𝑁𝑜. 𝑜𝑓 𝑏𝑒𝑙𝑡𝑠 =
5.96
𝑁𝑜. 𝑜𝑓 𝑏𝑒𝑙𝑡𝑠 = 12.58 𝑺𝒂𝒚 𝟏𝟑 𝒃𝒆𝒍𝒕𝒔
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
31
How long will it take for a 51 mm length
keyway to be milled if the milling
machine has a 24 teeth cutter turning at
130 rpm and feed rate of 0.127 mm per
tooth?
a. 0.281 min
b. 0.128 min
c. 0.218 min
d. 0812 min
REFRESHER 1
MACHINE DESIGN
2/20/2016
57
M
E
B
o
a
r
d
31
58
SOLUTION:
𝐿𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑐𝑢𝑡
𝑇𝑖𝑚𝑒 =
𝐶𝑢𝑡𝑡𝑖𝑛𝑔 𝑟𝑎𝑡𝑒
51
𝑇𝑖𝑚𝑒 =
0.127 24 130
𝑇𝑖𝑚𝑒 = 𝟎. 𝟏𝟐𝟖𝟕 𝒎𝒊𝒏
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
32
A double threaded bolt having a 5 threads
per inch. Compute the lead, in inches, of a
screw in one turn.
a. 0.2
b. 0.5
c. 0.4
d. 1.0
SOLUTION:
1
1
𝑝=
= = 0.2 𝑖𝑛
𝑇𝑃𝐼 5
𝐿 = 2𝑝 = 2 0.2 = 𝟎. 𝟒 𝒊𝒏
REFRESHER 1
MACHINE DESIGN
2/20/2016
59
M
E
B
o
a
r
d
A body weighing 1,000 lb falls 6 inches
and strikes a 2,000 lb per in spring. The
deformation of the spring is:
a. 1 in
b. 3 in
c. 2 in
d. 6 in
33
REFRESHER 1
MACHINE DESIGN
2/20/2016
60
M
E
B
o
a
r
d
33
61
SOLUTION:
𝑦
𝑊 ℎ+𝑦 =𝐹
2
𝑦
1,000 6 + 𝑦 = 2,000
2
2
𝑦 −𝑦−6=0
𝑦−3 𝑦+2 =0
𝑦 = 𝟑 𝒊𝒏
REFRESHER 1
MACHINE DESIGN
2/20/2016
A flange coupling has an outside diameter of 200
mm and connects two 50 mm shafts. There are
five 20 mm bolts on a 150 mm bolt circle. The
B
radial flange thickness is 30 mm. If the torsional
o
a
stress in the shaft is not to exceed 28 MPa,
r
determine the shearing stress in the bolts if
d
uniformly distributed.
34
a. 2.83 N/mm2
b. 4.83 N/mm2
c. 5.83 N/mm2
d. 6.83 N/mm2
REFRESHER 1
MACHINE DESIGN 2/20/2016
M
E
62
M
E
B
o
a
r
d
34
63
SOLUTION:
𝜋𝑑 3 𝑆𝑠
𝐷
𝑇=
=𝐹
16
2
𝜋𝑑 3 𝑆𝑠 𝜋 50 3 28
𝐹=
=
= 9,162.98 𝑁
8𝐷
8 150
𝐹 9,162.98
𝐹𝑏 = =
= 1,832.60 𝑁
𝑛
5
𝐹𝑏
4𝐹𝑏
4 1,832.60
𝑵
𝑆𝑠𝑏 =
=
=
= 𝟓. 𝟖𝟑
2
2
𝐴𝑏 𝜋 𝑑𝑏
𝜋 20
𝒎𝒎𝟐
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
A 1 ¾ inch single threaded, square
screw has a TPI of 4 and coefficient of
friction of 0.33. What is the efficiency?
a. 10.5%
c. 15.7%
b.
d.
12.7%
20.1%
35
REFRESHER 1
MACHINE DESIGN
2/20/2016
64
M
E
B
o
a
r
d
35
65
SOLUTION:
1
1
𝑖𝑛
𝑃𝑖𝑡𝑐ℎ =
= = 0.25
𝑇𝑃𝐼 4
𝑡𝑜𝑜𝑡ℎ
𝑝 0.25
𝐷𝑒𝑝𝑡ℎ = =
= 0.125 𝑖𝑛
2
2
𝐿𝑒𝑎𝑑 = 𝑝 = 0.25 𝑖𝑛
𝐷𝑚 = 𝐷𝑜 − 𝐷𝑒𝑝𝑡ℎ = 1.75 − 0.125 = 1.625 𝑖𝑛
𝐿𝑒𝑎𝑑
0.25
tan 𝑥 =
=
= 0.04897
𝜋𝐷𝑚 𝜋 1.625
tan 𝑥 1 − 𝑓 tan 𝑥
0.04897 1 − 0.33 0.04897
𝑒=
=
tan 𝑥 + 𝑓
0.04897 + 0.33
𝑒 = 0.1271 𝑜𝑟 𝟏𝟐. 𝟕𝟏%
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
36
A 20-tooth, 8 pitch, 1 inch wide, 20o
pinion transmits 5 hp at 1,725 rpm to a
60-tooth gear. Determine the driving
force in lb.
a. 145 lb
b. 155 lb
c. 50 lb
d. 255 lb
REFRESHER 1
MACHINE DESIGN
2/20/2016
66
M
E
B
o
a
r
d
36
67
SOLUTION:
𝑁𝑝
20
𝐷𝑝 =
= = 2.5 𝑖𝑛
𝑃𝑑
8
𝐷𝑝
63,000𝑃
𝑇 = 𝐹1
=
2
𝑁
2 63,000 𝑃 2 63,000 5
𝐹1 =
=
𝑁 𝐷𝑝
1,725 2.5
𝐹1 = 𝟏𝟒𝟔. 𝟎𝟗 𝒍𝒃
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
37
A plate-type clutch has the following
properties ro = 15 in, ri = 8 in, engagement
force of 160 lb (normal force), and turns at
3,000 rpm. The friction disc has a coefficient
of friction of 0.3. Determine the power that
can be transmitted by this system.
a. 16.3 hp
b. 26.3 hp
c. 36.3 hp
d. 46.3 hp
REFRESHER 1
MACHINE DESIGN
2/20/2016
68
M
E
B
o
a
r
d
37
69
SOLUTION:
𝑟𝑜 + 𝑟𝑖
15 + 8
𝑇𝑓 = 𝑓𝑁
= 0.3 160
2
2
𝑇𝑓 = 552 𝑖𝑛 ∙ 𝑙𝑏
𝑇𝑓 𝑁
552 3,000
𝑃𝑓 =
=
= 𝟐𝟔. 𝟑 𝒉𝒑
63,000
63,000
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
38
Determine the average pressure in a
plate clutch where the axial force is
1,300 lb, the inside radius of contact is ri
= 2.5 in, the outside radius is ro = 5 in.
Uniform wear is assumed.
a. 17.22 psi
b. 22.07 psi
c. 28.07 psi
d. 35.06 psi
REFRESHER 1
MACHINE DESIGN
2/20/2016
70
M
E
B
o
a
r
d
71
SOLUTION:
𝐹
𝐹
𝑝= =
𝐴 𝜋 𝑟𝑜 2 − 𝑟𝑖 2
1,300
𝑝=
=
𝟐𝟐.
𝟎𝟕
𝒑𝒔𝒊
𝜋 5 2 − 2.5 2
38
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
39
Determine the minimum pressure in a
plate clutch where the axial force is
1,300 lb, the inside radius of contact is ri
= 2.5 in, the outside radius is ro = 5 in.
Uniform wear is assumed.
a. 16.55 psi
b. 19.55 psi
c. 23.55 psi
d. 33.55 psi
REFRESHER 1
MACHINE DESIGN
2/20/2016
72
M
E
B
o
a
r
d
73
SOLUTION:
𝑟 = 𝑟𝑜 = 5 𝑖𝑛 → 𝑓𝑜𝑟 𝑚𝑖𝑛 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒
𝐶
𝐹
𝑝𝑚𝑖𝑛 = =
𝑟 2𝜋 𝑟𝑜 − 𝑟𝑖 𝑟
1,300
𝑝𝑚𝑖𝑛 =
= 𝟏𝟔. 𝟓𝟓 𝒑𝒔𝒊
2𝜋 5 − 2.5 5
39
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
40
Determine the maximum pressure in a
plate clutch where the axial force is
1,300 lb, the inside radius of contact is ri
= 2.5 in, the outside radius is ro = 5 in.
Uniform wear is assumed.
a. 23.1 psi
b. 33.1 psi
c. 43.1 psi
d. 49.1 psi
REFRESHER 1
MACHINE DESIGN
2/20/2016
74
M
E
B
o
a
r
d
40
75
SOLUTION:
𝑟 = 𝑟𝑖 = 2.5 𝑖𝑛 → 𝑓𝑜𝑟 max 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒
𝐶
𝐹
𝑝𝑚𝑎𝑥 = =
𝑟 2𝜋 𝑟𝑜 − 𝑟𝑖 𝑟
1,300
𝑝𝑚𝑎𝑥 =
= 𝟑𝟑. 𝟏 𝒑𝒔𝒊
2𝜋 5 − 2.5 2.5
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
41
If the ultimate shear stress of a steel
plate is 35,000 psi, what force is
necessary to punch a 1.5 in diameter
hole in a 1/8 in thick plate?
a. 20,617 lb b. 41,234 lb
c. 30,925 lb d. 61,850 lb
REFRESHER 1
MACHINE DESIGN
2/20/2016
76
M
E
B
o
a
r
d
77
SOLUTION:
𝐹 = 𝜋𝑑𝑡 𝑆𝑢 = 𝜋 1.5
1
8
35,000
𝐹 = 𝟐𝟎, 𝟔𝟏𝟔. 𝟕 𝒍𝒃
41
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
What load in Newton must be applied to
a 25 mm round steel bar 2.5 m long
(E=207 GPa) to stretch the bar 1.3 mm?
a. 52,840 N
c. 53,048 N
b.
d.
60,000 N
42,562 N
42
REFRESHER 1
MACHINE DESIGN
2/20/2016
78
M
E
B
o
a
r
d
42
79
SOLUTION:
𝜋 2
𝑦𝐴𝐸 𝑦 4 𝐷 𝐸
𝐹=
=
𝐿
𝐿
𝜋
1.3
0.025 2 207𝑥109
4
𝐹=
2,500
𝐹 = 𝟓𝟐, 𝟖𝟑𝟕. 𝟔𝟔 𝑵
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
43
A spur pinion rotates at 600 rpm and
transmits 25 kW to a mating gear. The pitch
diameter of the pinion is 100 mm, and the
pressure angle is 20o. Determine the
tangential load in Newton.
a. 7,960 N
b. 6,790 N
c. 3,980 N
d. 3,098 N
REFRESHER 1
MACHINE DESIGN
2/20/2016
80
M
E
B
o
a
r
d
81
SOLUTION:
60𝑃
𝐷
𝑇=
= 𝐹𝑡
2𝜋𝑁
2
60𝑃
60 25,000
𝐹𝑡 =
=
𝜋𝐷𝑁 𝜋 0.100 600
𝐹𝑡 = 𝟕, 𝟗𝟓𝟕. 𝟕𝟓 𝑵
43
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
44
A steel shaft 1.4375 inches in diameter
transmits 40 hp at 1,400 rpm. Assuming a
modulus of rigidity of 12 x 106 psi, find the
torsional deflection of the shaft in degrees
per foot length.
a. 0.624
b. 0.246
c. 0.426
d. 1.246
REFRESHER 1
MACHINE DESIGN
2/20/2016
82
M
E
B
o
a
r
d
44
83
SOLUTION:
63,000𝑃 𝜃𝐽𝐺
𝑇=
=
𝑁
𝐿
𝜃 63,000𝑃
63,000𝑃 180
=
= 𝜋
𝐿
𝐽𝐺𝑁
𝐷4 𝐺𝑁 𝜋
32
𝜃 32 63,00 180 𝑃
=
𝐿
𝜋 2 𝐷4 𝐺𝑁
𝜃
32 63,00 180 40 12
𝒐
= 2
=
𝟎.
𝟐𝟒𝟔
/𝒇𝒕
4
6
𝐿 𝜋 1.4375 12𝑥10 1,400
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
It is desired to check the design of a 2 in
medium steel shaft subjected to a turning
moment of 40,000 in.lb. Determine the factor
of safety used in the design if ultimate stress
is 50,000 psi.
a. 1.50 b. 2.50 c. 1.96 d. 4.95
45
REFRESHER 1
MACHINE DESIGN
2/20/2016
84
M
E
B
o
a
r
d
45
SOLUTION:
85
3
𝜋𝐷 𝑆𝑢
𝑆𝑢
𝑆𝑢
𝐹𝑆 =
=
=
16𝑇
𝑆𝑠
16𝑇
𝜋𝐷3
𝜋 2 3 50,000
𝐹𝑆 =
= 𝟏. 𝟗𝟔
16 40,000
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
46
A hydraulic turbine is a water-power plant is
rated at 12,000 hp. The steel vertical shaft
connecting the turbine and generator is 24-in
diameter and rotates at 60 rpm. Calculate the
maximum shearing stress developed in the
shaft at full load.
a. 4,640 psi
b. 3,240 psi
c. 4,150 psi
d. 1,450 psi
REFRESHER 1
MACHINE DESIGN
2/20/2016
86
M
E
B
o
a
r
d
46
87
SOLUTION:
63,000𝑃 𝜋𝐷 3 𝑆𝑠
𝑇=
=
𝑁
16
16 63,000𝑃
𝑆𝑠 =
𝜋𝐷 3 𝑁
16 63,000 12,000
𝑆𝑠 =
𝜋 24 3 60
REFRESHER 1
= 𝟒, 𝟔𝟒𝟐 𝒑𝒔𝒊
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
What factor of safety is needed for a 2.5
in. diameter shaft with an ultimate
strength of 65,000 psi to transmit 45,000
in.lb torque?
a. 4.34 b. 3.34
c. 4.43 d. 3.43
47
REFRESHER 1
MACHINE DESIGN
2/20/2016
88
M
E
B
o
a
r
d
47
89
SOLUTION:
𝑆𝑢
𝑆𝑢
𝜋𝐷3 𝑆𝑢
𝐹𝑆 =
=
=
16𝑇
𝑆𝑠
16𝑇
𝜋𝐷3
3
𝜋 2.5 65,000
𝐹𝑆 =
= 𝟒. 𝟒𝟑
16 45,000
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
48
What load P which causes a total
deformation of 0.0354 inch of a steel
rack which has a cross-section area of
4.5 sq. inches and a length of 6 ft?
a. 66,375 lb
b. 63,675 lb
c. 66,735 lb
d. 66,357 lb
REFRESHER 1
MACHINE DESIGN
2/20/2016
90
M
E
B
o
a
r
d
91
SOLUTION:
𝐸 = 30,000,000 𝑝𝑠𝑖 → 𝑓𝑜𝑟 𝑠𝑡𝑒𝑒𝑙
𝑦𝐴𝐸 0.0354 4.5 30,000,000
𝐹=
=
𝐿
6 12
𝐹 = 𝟔𝟔, 𝟑𝟕𝟓 𝒍𝒃
48
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
A round steel shaft transmits 3730 watts at
1800 rpm. The torsional deflection is not to
exceed 1 degree in a length equal to 20
diameters. Find the shaft diameter in mm.
a. 12.03 mm
c. 12.28 mm
b.
d.
13.28 mm
14.28 mm
49
REFRESHER 1
MACHINE DESIGN
2/20/2016
92
M
E
B
o
a
r
d
93
SOLUTION:
3 3,730 746
𝐻𝑃
𝐷=4
=4
25.4
𝑁
1,800
3
𝐷 = 𝟏𝟒. 𝟐𝟖 𝒎𝒎
49
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
Compute for the pitch angle of a bevel
gear given the pinion’s number of teeth
of 14 teeth and 42 teeth on the gear.
a. 18.4o
c. 33.4o
b.
d.
28.4o
38.4o
50
REFRESHER 1
MACHINE DESIGN
2/20/2016
94
M
E
B
o
a
r
d
95
SOLUTION:
𝑇
−1 𝑝
𝑃𝑖𝑡𝑐ℎ 𝑎𝑛𝑔𝑙𝑒 = 𝑡𝑎𝑛
𝑇𝑔
14
−1
𝒐
𝑃𝑖𝑡𝑐ℎ 𝑎𝑛𝑔𝑙𝑒 = 𝑡𝑎𝑛
= 𝟏𝟖. 𝟒
42
50
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
51
Determine the width of a key whose
strength is equal to the net strength of a
2.5 in circular shaft. The length of the
hub is 1 ½ times the shaft diameter.
a. 5/8 in
b. 1/2 in
c. 3/8 in
d. 1/4 in
REFRESHER 1
MACHINE DESIGN
2/20/2016
96
M
E
B
o
a
r
d
51
97
SOLUTION:
𝑆𝑠𝑠ℎ𝑎𝑓𝑡
16𝐹𝐷
2𝜋𝐷3
=
16𝑇
𝐹
= 𝑆𝑠𝑘𝑒𝑦 ;
=
3
𝜋𝐷
𝑤𝐿
𝐹
𝑤
3
𝐷
2
𝜋𝐷 𝜋 2.5 𝑖𝑛
𝑤=
=
= 0.654 𝑖𝑛;
12
12
𝟓
𝑆𝑎𝑦,
𝒘 = 𝒊𝒏
𝟖
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
52
What pressure is required for punching
a hole 3 inches in diameter through 1/4
inch steel stock?
98
a. 60 tons b. 40 tons c. 20 tons d. 37.92
SOLUTION:
𝑝 = 𝑑𝑡 80 = 3𝑖𝑛(1/4 𝑖𝑛)(80) = 𝟔𝟎 𝒕𝒐𝒏𝒔
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
The tooth thickness of a gear is 0.5 in
and its circular pitch is 1.0 in. Calculate
the dedendum of the gear.
a. 0.3183 b. 1.250 c. 0.3979 d. 0.1114
SOLUTION:
1.25 1.25𝑃𝑐
𝐷𝑒𝑑𝑒𝑛𝑑𝑢𝑚, 𝑑 =
𝑃𝑑
=
𝜋
1.25 1 𝑖𝑛
𝑑=
= 𝟎. 𝟑𝟗𝟕𝟗 𝒊𝒏
𝜋
REFRESHER 1
MACHINE DESIGN
53
2/20/2016
99
M
E
B
o
a
r
d
54
A horizontal beam 20 ft long is subjected to
a load 1000 lb located at its center. The
dimension of the beam is 3 x 6 inches,
respectively and its unit weight is 50 lb/ft.
Determine the radius of gyration of the
beam.
a. 1 in b. 2 in c. 1.732 in d. 3.512 in
REFRESHER 1
MACHINE DESIGN
2/20/2016
100
M
E
B
o
a
r
d
101
SOLUTION:
3
3
𝑏ℎ
3 6
𝐼=
=
= 54 𝑖𝑛4
12
12
𝐾=
54
REFRESHER 1
𝐼
=
𝐴
54
= 𝟏. 𝟕𝟑𝟐 𝒊𝒏
3 6
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
55
Determine a standard belt length of the
input and output shafts need to be
about 40 in apart. The input sheave
diameter is 10 in and output sheave
diameter of 24 in.
a.
c.
REFRESHER 1
134 mm
250 mm
b.
d.
3,419 mm
2,479 mm
MACHINE DESIGN
2/20/2016
102
M
E
B
o
a
r
d
103
SOLUTION:
𝐷2 − 𝐷1 2
𝐿 = 2𝐶 + 1.57 𝐷1 + 𝐷2 +
4𝐶
24 − 10
𝐿 = 2 40 + 1.57 10 + 24 +
4 40
𝐿 = 134.6 𝑖𝑛 = 𝟑, 𝟒𝟏𝟖. 𝟗 𝒎𝒎
2
55
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
56
A keyed sprocket delivers a torque of 778.8 N.m
thru the shaft of 54 mm OD. The key thickness
is 1.5875 cm and the width is 1.11 cm. Compute
the length of the same key. The permissible
stress value is 60 MPa for shear and 90 MPa for
tension.
a. 39.12 cm
b. 4.82 cm
c. 52.22 cm
d. 4.32 cm
REFRESHER 1
MACHINE DESIGN
2/20/2016
104
M
E
B
o
a
r
d
56
SOLUTION:
𝐹
2𝑇
𝑆𝑠 =
=
𝑤𝐿 𝐷𝑤𝐿
𝑇𝐷
𝐿=
2𝑤𝑆𝑠
2 778.8𝑁 ∙ 𝑚
𝐿=
0.054𝑚 0.0111𝑚 60𝑥106 𝑁/𝑚2
𝐿 = 0.0433 𝑚 = 𝟒. 𝟑𝟑 𝒄𝒎
REFRESHER 1
MACHINE DESIGN
2/20/2016
105
M
E
A rectangular key was used in a pulley
connected to a lineshaft with a power of 125 kW
at a speed of 900 rpm. If the shearing stress of
B
o
the shaft is 40 N/mm2 and the key to be 22
a
N/mm2. Determine the length of the rectangular
r
key if the width is one fourth that of the shaft
d
diameter.
57
a. 171.8 mm
b. 175.8 mm
c. 187.5 mm
d. 157.8 mm
REFRESHER 1
MACHINE DESIGN 2/20/2016
106
M
E
B
o
a
r
d
57
107
SOLUTION:
𝑇𝑠ℎ𝑎𝑓𝑡
𝐷=
3
60𝑃 30 125
=
=
= 1.326 𝑘𝑁 ∙ 𝑚
2𝜋𝑁
𝜋 900
16𝑇
=
𝜋𝑆𝑠
3
16 1.326 𝑘𝑁 ∙ 𝑚
= 0.05527 𝑚
2
𝜋 40,000 𝑘𝑁/𝑚
𝑇𝑠ℎ𝑎𝑓𝑡 = 𝑇𝑘𝑒𝑦 ;
2
𝜋𝐷3 𝑆𝑠𝑠
2
16
=
𝐷𝑤𝐿𝑆𝑠𝑘
2
𝜋𝐷 𝑆𝑠𝑠
𝜋𝐷 𝑆𝑠𝑠
𝜋𝐷𝑆𝑠𝑠
𝐿=
=
=
𝐷
8𝑤𝑆𝑠𝑘
2𝑆𝑠𝑘
8 4 𝑆𝑠𝑘
𝜋 55.27𝑚𝑚 40𝑀𝑃𝑎
𝐿=
= 𝟏𝟓𝟕. 𝟖 𝒎𝒎
2 22 𝑀𝑃𝑎
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
58
A
punching
machine
flywheel
accelerates from rest with α=10 rad/s^2.
In 20 sec, how many revolutions are
achieved?
a. 381.3 rev
b. 318.3 rev
c. 338.1 rev
d. 383.1 rev
REFRESHER 1
MACHINE DESIGN
2/20/2016
108
M
E
B
o
a
r
d
109
SOLUTION:
1 2
𝜃 = 𝜔1 𝑡 + 𝛼𝑡
2
1
2
𝜃 = 0 + 10 20
2
𝜃 = 2,000 𝑟𝑎𝑑 = 𝟑𝟏𝟖. 𝟑 𝒓𝒆𝒗
58
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
59
A cylindrical tank has an inside diameter
of 6 m and is subjected to an internal
pressure of 120 kPa. Determine the wall
thickness of the tank if the allowable
tangential stress is 40 MPa.
a. 25.4 mm
b. 12.7 mm
c. 19 mm
d. 9 mm
REFRESHER 1
MACHINE DESIGN
2/20/2016
110
M
E
B
o
a
r
d
111
SOLUTION:
𝑝𝐷
120 6
𝑡=
=
2𝑆𝑡 2 40,000
𝑡 = 0.009 𝑚 = 𝟗 𝒎𝒎
59
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
112
What should be the diameter of pulley in
inches with a belt speed of 4,500 fpm
and the motor running at 1,760 rpm?
a. 9.76 in
c. 7.76 in
b. 10 in
d. 8.76 in
60
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
113
SOLUTION:
𝑓𝑡 12 𝑖𝑛
4,500
𝑉
𝑚𝑖𝑛 1 𝑓𝑡
𝐷=
=
𝜋𝑁
𝜋 1,760 𝑟𝑝𝑚
𝐷 = 𝟗. 𝟕𝟔 𝒊𝒏
60
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
61
114
The section modulus of a rectangle of
base “b” and height “h” about its base
is:
a. bh2/6
b. bh2/12
c. bh3/12
d. bh3/3
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
62
115
A material that should be avoided in
constructing wood pattern:
a. sap wood
b. heart wood
c. kiln dried wood
d. core portion of wood
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
63
116
The arbitrary modification by removing
a small portion of a tooth material at the
tip of the gear tooth is called:
a. tip removal
b. tip relief
c. tip undercut
d. pressure angle cut
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
64
117
The gradual chemical reaction by other
substance such that metal is converted
to an oxide or other compounds.
a. corrosion
b. rusting
c. cheaping
d. weathering
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
65
118
Copper and most of its alloys can be
hardened by
a. patenting
b. case hardening
c. cold working
d. soaking
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
119
The reciprocal of diametral pitch
equivalent to the ratio of the pitch
diameter to the number of teeth:
a.
c.
lead
clearance
b.
d.
module
involute
66
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
67
120
Which of the following is not a
structural steel class?
a. low carbon steel
b. medium carbon steel
c. stainless steel
d. tool and die steel
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
68
121
A block-and-pulley system with one
fixed roped end is
a. a dependent system
b. an independent system
c. a popular system
d. a plane system
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
69
122
Another term for moment is
a.
b.
c.
d.
REFRESHER 1
torque
latent
resultant
opposite
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
70
123
It is a study of the geometry of motion
without consideration of the causes of
motion.
a. Kinematics
b. Kinetics
c. Physics
d. Translation
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
71
124
Improves the ratio of endurance
strength to ultimate strength of mediumcarbon steels:
a. copper
b. vanadium
c. tantalum
d. all of these
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
125
Increases hardenability of alloy steels:
a. manganese
b. molybdenum
c. phosphorous
d. all of these
72
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
73
126
Device used to guard surfaces against
marring:
a. locker
b. washer
c. bearing
d. oil seal
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
74
127
Which of the following steel contains
chromium?
a. SAE 2340
b. SAE 1230
c. SAE 4230
d. SAE 5240
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
75
128
The ratio of the pitch diameter in inches
to the number of teeth.
a. Pitch circle
b. English module
c. Module
d. Pitch diameter
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
Poisson’s ratio is the ratio of:
B
o
a
r
d
a.
b.
c.
d.
129
lateral stress to longitudinal stress
shear stress to shear strain
compressive stress to tensile stress
lateral strain to longitudinal strain
76
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
77
130
A machine tool in which metal is removed by
means of a revolving cutter with many teeth,
each tooth having a cutting edge which
removes its share of the stock.
a. Milling Machine
b. Lathe machine
c. Grinding Machine
d. Bench Machine
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
131
The quantity L/k is known as
a.
b.
c.
d.
stiffness ratio
roughness ratio
slenderness ratio
poisson’s ratio
78
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
79
132
The theoretical maximum load that an
initially straight column can support
without buckling.
a. Mcloid load
b. Evan’s load
c. Boyle’s load
d. Euler load
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
80
133
The difference between the inner and
outer dimensions.
a. circular clearance
b. diametral interference
c. interference
d. metric allowance
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
81
134
Assumed to be perfectly elastic within
its working range.
a. springs
b. beam
c. catenary
d. bearing
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
82
135
The critical slenderness ratios range
from
a. 8 to 10
b. 80 to 120
c. 20 to 80
d. 200
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
83
136
A real force on the body toward the
center of rotation.
a. centrifugal force
b. concentric force
c. acceleration force
d. centripetal force
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
84
137
The subject that encompasses the
procurement and production of metals.
a. Engineering Materials
b. Manufacturing
c. Metallurgy
d. Material Testing
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
85
138
For ductile materials, the material
strength used is
a. yield strength
b. ultimate strength
c. flexural strength
d. fracture strength
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
86
139
The resistance the object offers to
attempt to accelerate it in a linear
direction.
a. friction force
b. reaction force
c. inertia force
d. normal force
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
87
140
The rise in the outer edge of the
roadway
a. rise in elevation
b. super elevation
c. banking angle
d. banked
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
88
141
One of the methods of determining the
buckling load for an intermediate
column is
a. secant formula
b. sine rule
c. right hand rule
d. caliper rule
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
89
142
The capacity of metal to withstand load
without breaking is
a. strength
b. elasticity
c. stress
d. strain
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
90
143
The phenomenon of continuous
stretching under load even if the stress
is less than the yield point.
a. elasticity
b. plasticity
c. ductility
d. creep
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
91
144
The narrow surface followed along the
groove that gives the size of the drill
and keeps it straight/aligned.
a. web
b. tang
c. margin
d. shank
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
Steel is the generic term of variety of:
a. AISI metal
b. iron-carbon alloy
c. big iron
d. SAE metal
92
REFRESHER 1
MACHINE DESIGN
2/20/2016
145
M
E
B
o
a
r
d
93
146
This refers to the phenomena of
continuous stretch load even if the
stress is less than the material yield.
a. elasticity
b. ductility
c. creep
d. plasticity
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
147
Pipe color code for water.
a. blue
b. natural
c. green
d. white
94
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
95
148
The three main parts of a screw driver
are: handle, blade and ______________.
a. snap
b. head
c. shank
d. grip
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
SAE 1215 belongs to the steel family.
a. carbon
b. nickel
c. manganese
d. chrome
96
REFRESHER 1
MACHINE DESIGN
2/20/2016
149
M
E
B
o
a
r
d
97
150
Cutting lubricants used in drilling,
reaming and tapping of cast iron parts.
a. turpentine
b. soda water
c. soluble oil
d. dry
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
98
151
Anvil, hammer, burners are useful in
shop operation.
a. pattern
b. machine
c. foundry
d. forge
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
99
152
A machine member which is used to
connect shafts and to disconnect them
at will:
a. coupling
b. clutch
c. collar
d. universal joint
REFRESHER 1
MACHINE DESIGN
2/20/2016
M
E
B
o
a
r
d
100
153
Bearing surface that completely
surrounds the journal is also called
______________.
a. offset bearing
b. full bearing
c. centrally leaded bearin
d. babbit bearing
REFRESHER 1
MACHINE DESIGN
2/20/2016
An aim in life is the only
fortune worth finding.
And so, strike while the
iron is hot.