M22 Bolt Torque
An M22 8.8 bolt with a coarse M22×2.5 thread needs about 579.7 N·m (427.6 ft·lb) when dry and 430.5 N·m (317.5 ft·lb) when oiled, tightened to 70% of yield (clamp force 135.9 kN).
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 51.0 kN11459 lbf | 217.4 N·m160.3 ft·lb | 161.4 N·m119.1 ft·lb | 105.5 N·m77.8 ft·lb |
| 4.8 | 68.0 kN15278 lbf | 289.8 N·m213.8 ft·lb | 215.2 N·m158.7 ft·lb | 140.6 N·m103.7 ft·lb |
| 5.6 | 63.7 kN14323 lbf | 271.7 N·m200.4 ft·lb | 201.8 N·m148.8 ft·lb | 131.8 N·m97.2 ft·lb |
| 5.8 | 85.0 kN19098 lbf | 362.3 N·m267.2 ft·lb | 269.0 N·m198.4 ft·lb | 175.8 N·m129.6 ft·lb |
| 6.8 | 101.9 kN22917 lbf | 434.8 N·m320.7 ft·lb | 322.8 N·m238.1 ft·lb | 210.9 N·m155.6 ft·lb |
| 8.8 | 135.9 kN30557 lbf | 579.7 N·m427.6 ft·lb | 430.5 N·m317.5 ft·lb | 281.2 N·m207.4 ft·lb |
| 10.9 | 191.1 kN42970 lbf | 815.2 N·m601.3 ft·lb | 605.3 N·m446.5 ft·lb | 395.5 N·m291.7 ft·lb |
| 12.9 | 229.4 kN51564 lbf | 978.2 N·m721.5 ft·lb | 726.4 N·m535.8 ft·lb | 474.5 N·m350.0 ft·lb |
| A2-70 | 95.6 kN21485 lbf | 407.6 N·m300.6 ft·lb | 302.7 N·m223.2 ft·lb | 197.7 N·m145.8 ft·lb |
| A4-70 | 95.6 kN21485 lbf | 407.6 N·m300.6 ft·lb | 302.7 N·m223.2 ft·lb | 197.7 N·m145.8 ft·lb |
| A4-80 | 127.4 kN28647 lbf | 543.5 N·m400.8 ft·lb | 403.5 N·m297.6 ft·lb | 263.6 N·m194.4 ft·lb |
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 56.0 kN12579 lbf | 232.8 N·m171.7 ft·lb | 170.5 N·m125.7 ft·lb | 108.1 N·m79.8 ft·lb |
| 4.8 | 74.6 kN16772 lbf | 310.4 N·m228.9 ft·lb | 227.3 N·m167.6 ft·lb | 144.2 N·m106.4 ft·lb |
| 5.6 | 69.9 kN15724 lbf | 291.0 N·m214.6 ft·lb | 213.1 N·m157.2 ft·lb | 135.2 N·m99.7 ft·lb |
| 5.8 | 93.3 kN20965 lbf | 388.0 N·m286.1 ft·lb | 284.1 N·m209.5 ft·lb | 180.2 N·m132.9 ft·lb |
| 6.8 | 111.9 kN25158 lbf | 465.6 N·m343.4 ft·lb | 340.9 N·m251.5 ft·lb | 216.3 N·m159.5 ft·lb |
| 8.8 | 149.2 kN33543 lbf | 620.7 N·m457.8 ft·lb | 454.6 N·m335.3 ft·lb | 288.4 N·m212.7 ft·lb |
| 10.9 | 209.8 kN47171 lbf | 872.9 N·m643.8 ft·lb | 639.2 N·m471.5 ft·lb | 405.6 N·m299.1 ft·lb |
| 12.9 | 251.8 kN56605 lbf | 1047.5 N·m772.6 ft·lb | 767.1 N·m565.8 ft·lb | 486.7 N·m358.9 ft·lb |
| A2-70 | 104.9 kN23585 lbf | 436.5 N·m321.9 ft·lb | 319.6 N·m235.7 ft·lb | 202.8 N·m149.6 ft·lb |
| A4-70 | 104.9 kN23585 lbf | 436.5 N·m321.9 ft·lb | 319.6 N·m235.7 ft·lb | 202.8 N·m149.6 ft·lb |
| A4-80 | 139.9 kN31447 lbf | 581.9 N·m429.2 ft·lb | 426.2 N·m314.3 ft·lb | 270.4 N·m199.4 ft·lb |
Torque for M22 hex head bolts and nuts, standard ISO/ASME heads on steel with a 24.0 mm clearance hole. Friction μ applies to both the threads and the bearing face. Always follow the manufacturer's value where one exists.
M22 thread and dimensions
- Coarse thread
- M22×2.5 — pitch 2.5 mm
- Fine thread
- M22×1.5 — pitch 1.5 mm
- Tensile stress area Aₛ
- 303.4 mm² (coarse), 333.1 mm² (fine)
- Pitch diameter d₂
- 20.376 mm
- Tap drill
- 19.5 mm (coarse), 20.5 mm (fine)
- Wrench size (hex head)
- 34 mm (DIN: 32 mm)
- Clearance hole
- 24.0 mm
How the M22 torque is calculated
Preload is 70% of the bolt's yield strength times its tensile stress area. Torque then follows the ISO 16047 / VDI 2230 formula, which splits it into thread pitch, thread friction and friction under the head:
F = 70% × 640 MPa × 303.4 mm² = 135.9 kN
T = F × (0.16·P + 0.58·μ·d₂ + μ·Dₖₘ/2)
T = 135.9 kN × (0.16·2.5 + 0.58·0.15·20.38 + 0.15·29.00/2) mm = 579.7 N·m
Here d₂ is the pitch diameter and Dₖₘ the effective bearing diameter of the head (29.00 mm). Change the grade, lubrication or preload in the calculator below.
Frequently asked questions
What is the torque for an M22 8.8 bolt?
About 579.7 N·m (427.6 ft·lb) with dry threads, 430.5 N·m (317.5 ft·lb) with oiled threads and 281.2 N·m (207.4 ft·lb) with PTFE or moly paste, for a coarse M22×2.5 thread tightened to 70% of yield. The resulting clamp force is 135.9 kN.
What is the torque for an M22 10.9 bolt?
About 815.2 N·m (601.3 ft·lb) with dry threads, 605.3 N·m (446.5 ft·lb) with oiled threads and 395.5 N·m (291.7 ft·lb) with PTFE or moly paste, for a coarse M22×2.5 thread tightened to 70% of yield. The resulting clamp force is 191.1 kN.
What size wrench fits an M22 bolt?
A standard M22 hex head bolt or nut takes a 34 mm (DIN: 32 mm) wrench or socket.
What drill size do I need to tap M22?
Use a 19.5 mm drill for M22×2.5 and 20.5 mm for M22×1.5.