M30 Bolt Torque
An M30 8.8 bolt with a coarse M30×3.5 thread needs about 1462.1 N·m (1078.4 ft·lb) when dry and 1086.7 N·m (801.5 ft·lb) when oiled, tightened to 70% of yield (clamp force 251.1 kN).
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 94.2 kN21172 lbf | 548.3 N·m404.4 ft·lb | 407.5 N·m300.6 ft·lb | 266.7 N·m196.7 ft·lb |
| 4.8 | 125.6 kN28230 lbf | 731.1 N·m539.2 ft·lb | 543.4 N·m400.8 ft·lb | 355.6 N·m262.3 ft·lb |
| 5.6 | 117.7 kN26465 lbf | 685.4 N·m505.5 ft·lb | 509.4 N·m375.7 ft·lb | 333.4 N·m245.9 ft·lb |
| 5.8 | 157.0 kN35287 lbf | 913.8 N·m674.0 ft·lb | 679.2 N·m500.9 ft·lb | 444.6 N·m327.9 ft·lb |
| 6.8 | 188.4 kN42344 lbf | 1096.6 N·m808.8 ft·lb | 815.0 N·m601.1 ft·lb | 533.5 N·m393.5 ft·lb |
| 8.8 | 251.1 kN56459 lbf | 1462.1 N·m1078.4 ft·lb | 1086.7 N·m801.5 ft·lb | 711.3 N·m524.6 ft·lb |
| 10.9 | 353.2 kN79396 lbf | 2056.1 N·m1516.5 ft·lb | 1528.2 N·m1127.1 ft·lb | 1000.2 N·m737.7 ft·lb |
| 12.9 | 423.8 kN95275 lbf | 2467.3 N·m1819.8 ft·lb | 1833.8 N·m1352.6 ft·lb | 1200.3 N·m885.3 ft·lb |
| A2-70 | 176.6 kN39698 lbf | 1028.1 N·m758.3 ft·lb | 764.1 N·m563.6 ft·lb | 500.1 N·m368.9 ft·lb |
| A4-70 | 176.6 kN39698 lbf | 1028.1 N·m758.3 ft·lb | 764.1 N·m563.6 ft·lb | 500.1 N·m368.9 ft·lb |
| A4-80 | 235.4 kN52930 lbf | 1370.7 N·m1011.0 ft·lb | 1018.8 N·m751.4 ft·lb | 666.8 N·m491.8 ft·lb |
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 104.4 kN23461 lbf | 591.2 N·m436.0 ft·lb | 432.7 N·m319.2 ft·lb | 274.3 N·m202.3 ft·lb |
| 4.8 | 139.1 kN31282 lbf | 788.3 N·m581.4 ft·lb | 577.0 N·m425.6 ft·lb | 365.7 N·m269.7 ft·lb |
| 5.6 | 130.5 kN29327 lbf | 739.0 N·m545.1 ft·lb | 540.9 N·m399.0 ft·lb | 342.8 N·m252.9 ft·lb |
| 5.8 | 173.9 kN39102 lbf | 985.3 N·m726.7 ft·lb | 721.2 N·m531.9 ft·lb | 457.1 N·m337.1 ft·lb |
| 6.8 | 208.7 kN46923 lbf | 1182.4 N·m872.1 ft·lb | 865.5 N·m638.3 ft·lb | 548.5 N·m404.6 ft·lb |
| 8.8 | 278.3 kN62564 lbf | 1576.5 N·m1162.8 ft·lb | 1153.9 N·m851.1 ft·lb | 731.4 N·m539.4 ft·lb |
| 10.9 | 391.4 kN87980 lbf | 2217.0 N·m1635.2 ft·lb | 1622.7 N·m1196.9 ft·lb | 1028.5 N·m758.6 ft·lb |
| 12.9 | 469.6 kN105576 lbf | 2660.4 N·m1962.2 ft·lb | 1947.3 N·m1436.2 ft·lb | 1234.2 N·m910.3 ft·lb |
| A2-70 | 195.7 kN43990 lbf | 1108.5 N·m817.6 ft·lb | 811.4 N·m598.4 ft·lb | 514.2 N·m379.3 ft·lb |
| A4-70 | 195.7 kN43990 lbf | 1108.5 N·m817.6 ft·lb | 811.4 N·m598.4 ft·lb | 514.2 N·m379.3 ft·lb |
| A4-80 | 260.9 kN58654 lbf | 1478.0 N·m1090.1 ft·lb | 1081.8 N·m797.9 ft·lb | 685.7 N·m505.7 ft·lb |
Torque for M30 hex head bolts and nuts, standard ISO/ASME heads on steel with a 33.0 mm clearance hole. Friction μ applies to both the threads and the bearing face. Always follow the manufacturer's value where one exists.
M30 thread and dimensions
- Coarse thread
- M30×3.5 — pitch 3.5 mm
- Fine thread
- M30×2 — pitch 2 mm
- Tensile stress area Aₛ
- 560.6 mm² (coarse), 621.2 mm² (fine)
- Pitch diameter d₂
- 27.727 mm
- Tap drill
- 26.5 mm (coarse), 28 mm (fine)
- Wrench size (hex head)
- 46 mm
- Clearance hole
- 33.0 mm
How the M30 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 × 560.6 mm² = 251.1 kN
T = F × (0.16·P + 0.58·μ·d₂ + μ·Dₖₘ/2)
T = 251.1 kN × (0.16·3.5 + 0.58·0.15·27.73 + 0.15·39.50/2) mm = 1462.1 N·m
Here d₂ is the pitch diameter and Dₖₘ the effective bearing diameter of the head (39.50 mm). Change the grade, lubrication or preload in the calculator below.
Frequently asked questions
What is the torque for an M30 8.8 bolt?
About 1462.1 N·m (1078.4 ft·lb) with dry threads, 1086.7 N·m (801.5 ft·lb) with oiled threads and 711.3 N·m (524.6 ft·lb) with PTFE or moly paste, for a coarse M30×3.5 thread tightened to 70% of yield. The resulting clamp force is 251.1 kN.
What is the torque for an M30 10.9 bolt?
About 2056.1 N·m (1516.5 ft·lb) with dry threads, 1528.2 N·m (1127.1 ft·lb) with oiled threads and 1000.2 N·m (737.7 ft·lb) with PTFE or moly paste, for a coarse M30×3.5 thread tightened to 70% of yield. The resulting clamp force is 353.2 kN.
What size wrench fits an M30 bolt?
A standard M30 hex head bolt or nut takes a 46 mm wrench or socket.
What drill size do I need to tap M30?
Use a 26.5 mm drill for M30×3.5 and 28 mm for M30×2.