Bolt Torque Specs
Typical dry-thread torque values for SAE and metric bolt grades.
Reference
Dry, clean threads. Lubricated threads reduce torque by ~25%. Always check manufacturer spec.
SAE grade 5 (medium carbon, heat-treated)
| Size | Thread | Torque (ft-lb) | Torque (N·m) |
|---|---|---|---|
| 1/4" | 20 | 9 | 12 |
| 5/16" | 18 | 18 | 24 |
| 3/8" | 16 | 31 | 42 |
| 7/16" | 14 | 50 | 68 |
| 1/2" | 13 | 76 | 103 |
| 9/16" | 12 | 111 | 150 |
| 5/8" | 11 | 150 | 203 |
| 3/4" | 10 | 266 | 360 |
| 7/8" | 9 | 430 | 583 |
| 1" | 8 | 644 | 873 |
SAE grade 8 (alloy steel)
| Size | Thread | Torque (ft-lb) | Torque (N·m) |
|---|---|---|---|
| 1/4" | 20 | 12 | 16 |
| 5/16" | 18 | 25 | 34 |
| 3/8" | 16 | 44 | 60 |
| 7/16" | 14 | 70 | 95 |
| 1/2" | 13 | 107 | 145 |
| 9/16" | 12 | 157 | 213 |
| 5/8" | 11 | 215 | 292 |
| 3/4" | 10 | 380 | 515 |
| 7/8" | 9 | 606 | 822 |
| 1" | 8 | 909 | 1233 |
Metric class 8.8
| Size | Pitch | Torque (N·m) | Torque (ft-lb) |
|---|---|---|---|
| M4 | 0.7 | 3 | 2 |
| M5 | 0.8 | 6 | 4 |
| M6 | 1.0 | 10 | 7 |
| M8 | 1.25 | 25 | 18 |
| M10 | 1.5 | 50 | 37 |
| M12 | 1.75 | 87 | 64 |
| M14 | 2.0 | 139 | 103 |
| M16 | 2.0 | 215 | 159 |
| M20 | 2.5 | 422 | 311 |
| M24 | 3.0 | 732 | 540 |
Metric class 10.9
| Size | Pitch | Torque (N·m) | Torque (ft-lb) |
|---|---|---|---|
| M4 | 0.7 | 4 | 3 |
| M5 | 0.8 | 9 | 7 |
| M6 | 1.0 | 15 | 11 |
| M8 | 1.25 | 36 | 26 |
| M10 | 1.5 | 72 | 53 |
| M12 | 1.75 | 126 | 93 |
| M14 | 2.0 | 200 | 148 |
| M16 | 2.0 | 310 | 229 |
| M20 | 2.5 | 607 | 448 |
| M24 | 3.0 | 1050 | 775 |
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