U.S. Bolts - Tightening Torques
Recommended bolt torques.
The tightening torques below are for imperial U.S. bolts with tension approximately 70% of yield strength.
| Size (in) | Torque (lbf ft) | |||||||
|---|---|---|---|---|---|---|---|---|
| SAE Grade 2 | SAE Grade 5 | SAE Grade 8 | 18-8 S/S | |||||
| Coarse | Fine | Coarse | Fine | Coarse | Fine | Coarse | Fine | |
| 1/4 | 4 | 4.7 | 6.3 | 7.3 | 9 | 10 | 6.3 | 7.8 |
| 5/16 | 8 | 9 | 13 | 14 | 18 | 20 | 11 | 11.8 |
| 3/8 | 15 | 17 | 23 | 26 | 33 | 37 | 20 | 22 |
| 7/16 | 24 | 27 | 37 | 41 | 52 | 58 | 31 | 33 |
| 1/2 | 37 | 41 | 57 | 64 | 80 | 90 | 43 | 45 |
| 9/16 | 53 | 59 | 82 | 91 | 115 | 129 | 57 | 63 |
| 5/8 | 73 | 83 | 112 | 128 | 159 | 180 | 93 | 104 |
| 3/4 | 115 | 138 | 200 | 223 | 282 | 315 | 128 | 124 |
| 7/8 | 129 | 144 | 322 | 355 | 454 | 501 | 194 | 193 |
| 1 | 188 | 210 | 483 | 541 | 682 | 764 | 287 | 289 |
- 1 inch = 25.4 mm
The values are for slightly lubricated bolts. For dry bolts increase the torques with approximately 30%.
