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Bolt torque requirements metric and standard
Bolt
torque specification charts
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Below is a list of bolt torques compiles from various machine
tool manufacturers. In general the proper torque spec is usually
around 65-70% of the failure torque rate. The below chart refers to
usage in steel. Proper torque spec varies depending on the material,
bolt grade or wether lubrication is used such as oil, wax, or
anti-seize Always go to the manufacturer for proper torque specs if
needed. Lubrication added to a dry bolt will typically reduce the
torque value 15-25%. The below is approximate values and have not
been validated for accuracy. If you require additional torque specs
for other applications search on the internet or get in tough with
your bolt supplier.
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Capturing bearing races in housings |
Setting preload on certain types of bearings |
Smaller size bolts which can be easily over torqued. |
Bolts in soft materials such as aluminum Example-hydraulic
manifolds |
Any housing or thin wall material that has a chance to be
distorted if over tightened or an uneven torque is
applied. |
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Metric bolt torque spec settings chart
(Torque in pounds/foot)
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Hex head cap screws |
Socket head cap
screws |
Socket head cap screw |
Grade 8.8 |
Grade 10.9 |
Grade 12.9 |
M4 x .70 |
1.65 |
|
3.3 |
M5 x .80 |
4.13 |
|
6.9 |
M6 x 1.0 |
7.1 |
11 |
11.6 |
M7 x 1.0 |
12 |
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M8 x 1.0 |
18 |
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M8 x 1.25 |
17 |
26 |
29 |
M10 x 1.0 |
39. |
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M10 x 1.25 |
36 |
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M10 x 1.5 |
34 |
51 |
57 |
M12 x 1.25 |
65 |
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M12 x 1.5 |
63 |
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M12 x 1.75 |
59 |
88 |
99 |
M14 x 1.5 |
102 |
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M14 x 2 |
94 |
139 |
158 |
M16 x 2 |
146 |
210 |
250 |
M18 x 2.5 |
210 |
|
341 |
M20 x 2.5 |
292 |
|
489 |
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Grade
10.9
(below) |
M22 |
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559 |
M24 |
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705 |
M30 |
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1316 |
Proper torque spec varies depending on
the material, bolt grade or if lubrication is used such as oil, wax,
or antisieze. Always go to the manufacturer for proper torque specs.
The chart above is approximate values and have not been validated
for accuracy. The numbers above have been compiled from a couple
different machine builders factory bolt spec
settings. |
Standard bolt torque spec settings chart
(Torque in foot-pounds)
|
Hex head |
Socket head cap
screws |
Grade 5 |
Grade 7 |
Grade 8 |
Bolt Dia. |
Thread per inch |
Dry |
Oiled |
Dry |
Oiled |
Dry |
Oiled |
Dry |
Oiled |
1/4 |
20 |
8 |
6 |
10 |
8 |
12 |
9 |
14 |
11 |
1/4 |
28 |
10 |
7 |
12 |
9 |
14 |
10 |
16 |
13 |
5/16 |
18 |
17 |
13 |
21 |
16 |
25 |
18 |
29 |
23 |
5/16 |
24 |
19 |
14 |
24 |
18 |
29 |
20 |
33 |
26 |
3/8 |
16 |
30 |
23 |
40 |
30 |
45 |
35 |
49 |
39 |
3/8 |
24 |
35 |
25 |
45 |
35 |
50 |
40 |
54 |
44 |
7/16 |
14 |
50 |
35 |
60 |
45 |
70 |
55 |
76 |
61 |
7/16 |
20 |
55 |
40 |
70 |
50 |
80 |
60 |
85 |
68 |
1/2 |
13 |
75 |
55 |
95 |
70 |
110 |
80 |
113 |
90 |
1/2 |
20 |
90 |
65 |
100 |
80 |
120 |
90 |
126 |
100 |
9/16 |
12 |
110 |
80 |
135 |
100 |
150 |
110 |
163 |
130 |
9/16 |
18 |
120 |
90 |
150 |
110 |
170 |
130 |
181 |
144 |
5/8 |
11 |
150 |
110 |
140 |
190 |
220 |
170 |
230 |
184 |
5/8 |
18 |
180 |
130 |
210 |
160 |
240 |
180 |
255 |
204 |
3/4 |
10 |
260 |
200 |
320 |
240 |
380 |
280 |
400 |
320 |
3/4 |
16 |
300 |
220 |
360 |
280 |
420 |
320 |
440 |
350 |
7/8 |
9 |
430 |
320 |
520 |
400 |
600 |
460 |
640 |
510 |
7/8 |
14 |
470 |
360 |
580 |
440 |
660 |
500 |
700 |
560 |
1 |
8 |
640 |
480 |
800 |
600 |
900 |
680 |
980 |
780 |
1 |
12 |
710 |
530 |
860 |
666 |
990 |
740 |
1060 |
845 |
Proper torque spec
varies depending on the material, bolt grade or if lubrication is
used such as oil, wax, or anti-seize. Always go to the manufacturer
for proper torque specifications. The chart above is an approximate
estimate of torque values and have not been validated for accuracy.
The numbers above have been compiled from various machine builder
specs and other
resources. |
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