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Bolt torque requirements metric and standard
Bolt torque specification charts

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.
Possible situations where proper bolt torque may be necessary related to machine tool repair.
  • 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.


Metric bolt torque spec settings chart

(Torque in pounds/foot)

 
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
M8 x 1.0
 18
M8 x 1.25
 17 26 29
M10 x 1.0
 39.
M10 x 1.25
 36
M10 x 1.5
 34 51 57
M12 x 1.25
 65
M12 x 1.5
 63
M12 x 1.75
 59 88 99
M14 x 1.5
 102
M14 x 2
 94 139 158
M16 x 2
 146 210 250
M18 x 2.5
 210 341
M20 x 2.5
 292 489
Grade 10.9
(below)
M22
 559
M24
 705
M30
 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.