Torque Information
Adjustment of Torque for Tightening Method and Friction Coefficient
Two major points have to be accounted for when installing a fastener.
- 1. Inaccuracy of torque wrench tightening method can range anywhere from ±17 to ±23%
- 2. The friction coefficient changes when using lubrication on the thread.
1. Inaccuracy of tightening method
A torque wrench has a “scatter” (tolerance) of ±17% to ±23%. We must account for this in order not to over-tighten the fastener.
Example: |
Torque should be set to 1,854 Nm (mean torque) on the torque wrench |
The accuracy of the tightening method needs to be accounted for, in order to not over-tighten the fastener.
2. Friction coefficient
The surface condition of a fastener may change the torque that can be applied and needs to be accounted for.
Friction coefficients for standard finish fasteners |
|||
Surface Condition | Lubrication Condition | ||
---|---|---|---|
Screw | Nut | Oiled | MoS2-Paste |
– no treatment – phosphate | – no treatment | 0.12-0.18 | 0.05-0.10 |
– electroplated appx. 8 μm | – electroplated appx. 5 μm | 0.12-0.18 | |
– dacromet-coated 6-8 μm | – dacromet-coated 6-8 μm | 0.10-0.14 |
Example: | A M30-12.9 fastener using MoS2 paste.
Torque should be set to 1,602 Nm (mean torque) on the torque wrench |
The accuracy of the tightening method, as well as the change in friction, needs to be accounted for in order not to over-tighten the fastener.
General Torque Figures
A torque value will be influenced by the fastening methods and tools used. The only way to determine an exact torque value is by actual application. The following figures are general guidelines only.
Figures in ft. lbs.
Thread Diameter | Property Class | ||
---|---|---|---|
8.8 | 10.9 | 12.9 | |
M3 | 0.80 | 1.1 | 1.3 |
M4 | 1.8 | 2.6 | 3.1 |
M5 | 3.6 | 5.1 | 6.2 |
M6 | 7 | 10 | 12 |
M8 | 17 | 25 | 29 |
M10 | 33 | 48 | 58 |
M12 | 60 | 85 | 102 |
M14 | 97 | 137 | 165 |
M16 | 150 | 208 | 250 |
M18 | 201 | 287 | 342 |
M20 | 282 | 398 | 479 |
M22 | 390 | 552 | 664 |
M24 | 499 | 750 | 843 |
M27 | 746 | 1051 | 1266 |
M30 | 982 | 1383 | 1657 |
M33 | 1331 | 1875 | 2250 |
M36 | 1717 | 2407 | 2895 |
M39 | 2220 | 3120 | 3750 |
M42 | 2737 | 3840 | 4638 |
M45 | 3390 | 4762 | 5722 |
M48 | 4095 | 5775 | 6825 |
M52 | 5250 | 7387 | 9000 |
M56 | 6547 | 9225 | 11280 |
M60 | 8175 | 11475 | 13800 |
M64 | 9900 | 13950 | 17175 |
M68 | 12000 | 16950 | 20100 |
M72 | 14250 | 20100 | 24000 |
M76 | 16800 | 23625 | 28350 |
M80 | 19725 | 27600 | 33375 |
M85 | 24000 | 33225 | 40125 |
M90 | 28350 | 38925 | 47700 |
M95 | 33450 | 46875 | 56250 |
M100 | 39000 | 54750 | 66000 |
Torque – Metric Fasteners
Diameter | Recommended Seating Torque (NM) | Proof Torque min. (NM) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ISO 4762DIN 912 | DIN 7984 | ISO 10642DIN 7991 | ISO 7380 | ISO 7379 | ISO 4014/ 4017DIN 931 / DIN 933 | ISO 4162 | ISO4026 / 4027 4028 / 4029 | ||||||
Socket CapScrews | Low HeadSocket Cap
Screws |
Flat HeadCountersunk
Socket Cap Screws |
Button HeadSocket Cap
Screws |
SocketShoulder
Screws |
Hexagon HeadCap Screws | Hexagon FlangeScrews | Socket SetScrews | ||||||
10.9 | 12.9 | 10.9 | 10.9 | 12.9 | 10.9 | 12.9 | 12.9 | 10.9 | 12.9 | 10.9 | 12.9 | 45H | |
M1.6 | 0.25 | 0.30 | |||||||||||
M2 | 0.50 | 0.63 | |||||||||||
M2.5 | 1.03 | 1.27 | |||||||||||
M3 | 1.83 | 2.20 | 1.15 | 1.15 | 1.35 | 1.15 | 1.35 | 0.90 | |||||
M4 | 4.27 | 4.83 | 2.70 | 2.70 | 3.10 | 2.70 | 3.10 | 2.50 | |||||
M5 | 8.64 | 10.0 | 5.40 | 5.40 | 6.10 | 5.40 | 6.10 | 8.64 | 10.0 | 8.64 | 10.0 | 5.00 | |
M6 | 14.7 | 16.8 | 9.15 | 9.15 | 10.5 | 9.15 | 10.5 | 5.6 | 14.7 | 16.8 | 14.7 | 16.8 | 8.50 |
M6.5 | 5.6 | ||||||||||||
M8 | 35.6 | 41.0 | 22.0 | 22.0 | 26.0 | 22.0 | 26.0 | 9.6 | 35.6 | 41.0 | 35.6 | 41.0 | 20.0 |
M10 | 70.6 | 81.0 | 44.0 | 44.0 | 52.0 | 44.0 | 52.0 | 25 | 70.6 | 81.0 | 70.6 | 81.0 | 40.0 |
M12 | 123 | 142 | 77.0 | 77.0 | 90.0 | 77.0 | 90.0 | 51 | 123 | 142 | 123 | 142 | 65.0 |
M13 | 51 | ||||||||||||
M14 | 195 | 226 | 122 | 122 | 143 australianpharmall.com | 195 | 226 | 195 | 226 | 65.0 | |||
M16 | 305 | 350 | 190 | 190 | 225 | 190 | 225 | 92 | 305 | 350 | 305 | 350 | 160 |
M18 | 420 | 485 | 262 | 420 | 485 | 310 | |||||||
M20 | 596 | 685 | 371 | 370 | 440 | 245 | 596 | 685 | 310 | ||||
M22 | 811 | 930 | 811 | 930 | |||||||||
M24 | 1031 | 1180 | 1031 | 1180 | |||||||||
M25 | 485 | ||||||||||||
M27 | 1508 | 1730 | 1508 | 1730 | |||||||||
M30 | 2048 | 2380 | 2048 | 2380 | |||||||||
M33 | 2787 | 3262 | |||||||||||
M36 | 3580 | 4190 | |||||||||||
M39 | 4633 | 5420 |
Torque – Imperial Fasteners
Diameter | Recommended Seating Torque (in-lb) | Proof Torque min. (in-lb) | ||||||
---|---|---|---|---|---|---|---|---|
ASME B18.3 | ASME B18.2.1 | IFI-111 | ASME B18.3 | |||||
Socket CapScrews | Low HeadSocket Cap
Screws |
Flat HeadCountersunk
Socket Cap Screws |
Button HeadSocket Cap
Screws |
Socket Shoulder Screws | Hexagon HeadCap Screws SAE J429
Grade 8 |
Hexagon FlangeScrews SAE J429
Grade 8 |
Socket SetScrews | |
#0 | 2.26 | 1.42 | 1.42 | 1.1 | ||||
#1 | 4.01 | 2.52 | 2.52 | 2.1 | ||||
#2 | 6.65 | 4.18 | 4.18 | 2.1 | ||||
#3 | 10.1 | 6.33 | 6.33 | 6.0 | ||||
#4 | 14.1 | 8.88 | 8.88 | 8.88 | 6.0 | |||
#5 | 20.8 | 13.1 | 13.1 | 13.1 | 11 | |||
#6 | 26.2 | 16.5 | 16.5 | 16.5 | 11 | |||
#8 | 48.0 | 30.1 | 30.1 | 30.1 | 23 | |||
#10 | 69.5 | 43.7 | 43.7 | 43.7 | 40 | |||
1/4 | 166 | 104 | 104 | 104 | 35 | 134 | 134 | 94 |
5/16 | 342 | 215 | 215 | 215 | 90 | 277 | 277 | 183 |
3/8 | 608 | 382 | 382 | 382 | 200 | 491 | 491 | 317 |
7/16 | 973 | 611 | 611 | 785 | 785 | 502 | ||
1/2 | 1484 | 931 | 931 | 931 | 363 | 1202 | 1202 | 750 |
9/16 | 1732 | 1732 | ||||||
5/8 | 2792 | 1722 | 1722 | 1722 | 922 | 2386 | 2386 | 1460 |
3/4 | 4952 | 3054 | 1864 | 4225 | 4225 | 2520 | ||
7/8 | 7991 | 4928 | 6823 | 5750 | ||||
1 | 11979 | 7388 | 3443 | 10226 | 8000 | |||
1-1/8 | 16968 | 10464 | 14485 | |||||
1-1/4 | 23944 | 14766 | 5637 | 20442 | ||||
1-3/8 | 31394 | 19360 | 26806 | |||||
1-1/2 | 41611 | 25692 | 12002 | 35573 |
All information is strictly informative