M7 Bolt Torque
An M7 8.8 bolt with a coarse M7×1 thread needs about 17.9 N·m (13.2 ft·lb) when dry and 13.4 N·m (9.88 ft·lb) when oiled, tightened to 70% of yield (clamp force 12.9 kN).
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 4.85 kN1090 lbf | 6.71 N·m4.95 ft·lb | 5.02 N·m3.71 ft·lb | 3.34 N·m2.46 ft·lb |
| 4.8 | 6.46 kN1453 lbf | 8.95 N·m6.60 ft·lb | 6.70 N·m4.94 ft·lb | 4.45 N·m3.28 ft·lb |
| 5.6 | 6.06 kN1362 lbf | 8.39 N·m6.19 ft·lb | 6.28 N·m4.63 ft·lb | 4.17 N·m3.08 ft·lb |
| 5.8 | 8.08 kN1817 lbf | 11.2 N·m8.25 ft·lb | 8.37 N·m6.18 ft·lb | 5.56 N·m4.10 ft·lb |
| 6.8 | 9.70 kN2180 lbf | 13.4 N·m9.90 ft·lb | 10.0 N·m7.41 ft·lb | 6.68 N·m4.92 ft·lb |
| 8.8 | 12.9 kN2907 lbf | 17.9 N·m13.2 ft·lb | 13.4 N·m9.88 ft·lb | 8.90 N·m6.57 ft·lb |
| 9.8 | 14.5 kN3270 lbf | 20.1 N·m14.8 ft·lb | 15.1 N·m11.1 ft·lb | 10.0 N·m7.39 ft·lb |
| 10.9 | 18.2 kN4087 lbf | 25.2 N·m18.6 ft·lb | 18.8 N·m13.9 ft·lb | 12.5 N·m9.23 ft·lb |
| 12.9 | 21.8 kN4905 lbf | 30.2 N·m22.3 ft·lb | 22.6 N·m16.7 ft·lb | 15.0 N·m11.1 ft·lb |
| A2-70 | 9.09 kN2044 lbf | 12.6 N·m9.28 ft·lb | 9.42 N·m6.95 ft·lb | 6.26 N·m4.62 ft·lb |
| A4-70 | 9.09 kN2044 lbf | 12.6 N·m9.28 ft·lb | 9.42 N·m6.95 ft·lb | 6.26 N·m4.62 ft·lb |
| A4-80 | 12.1 kN2725 lbf | 16.8 N·m12.4 ft·lb | 12.6 N·m9.26 ft·lb | 8.34 N·m6.15 ft·lb |
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 5.23 kN1176 lbf | 7.10 N·m5.24 ft·lb | 5.26 N·m3.88 ft·lb | 3.42 N·m2.52 ft·lb |
| 4.8 | 6.97 kN1568 lbf | 9.47 N·m6.98 ft·lb | 7.02 N·m5.18 ft·lb | 4.56 N·m3.37 ft·lb |
| 5.6 | 6.54 kN1470 lbf | 8.88 N·m6.55 ft·lb | 6.58 N·m4.85 ft·lb | 4.28 N·m3.16 ft·lb |
| 5.8 | 8.72 kN1960 lbf | 11.8 N·m8.73 ft·lb | 8.77 N·m6.47 ft·lb | 5.71 N·m4.21 ft·lb |
| 6.8 | 10.5 kN2352 lbf | 14.2 N·m10.5 ft·lb | 10.5 N·m7.76 ft·lb | 6.85 N·m5.05 ft·lb |
| 8.8 | 13.9 kN3136 lbf | 18.9 N·m14.0 ft·lb | 14.0 N·m10.4 ft·lb | 9.13 N·m6.73 ft·lb |
| 9.8 | 15.7 kN3528 lbf | 21.3 N·m15.7 ft·lb | 15.8 N·m11.6 ft·lb | 10.3 N·m7.57 ft·lb |
| 10.9 | 19.6 kN4410 lbf | 26.6 N·m19.6 ft·lb | 19.7 N·m14.6 ft·lb | 12.8 N·m9.47 ft·lb |
| 12.9 | 23.5 kN5292 lbf | 32.0 N·m23.6 ft·lb | 23.7 N·m17.5 ft·lb | 15.4 N·m11.4 ft·lb |
| A2-70 | 9.81 kN2205 lbf | 13.3 N·m9.82 ft·lb | 9.87 N·m7.28 ft·lb | 6.42 N·m4.73 ft·lb |
| A4-70 | 9.81 kN2205 lbf | 13.3 N·m9.82 ft·lb | 9.87 N·m7.28 ft·lb | 6.42 N·m4.73 ft·lb |
| A4-80 | 13.1 kN2940 lbf | 17.8 N·m13.1 ft·lb | 13.2 N·m9.70 ft·lb | 8.56 N·m6.31 ft·lb |
Torque for M7 hex head bolts and nuts, standard ISO/ASME heads on steel with a 7.6 mm clearance hole. Friction μ applies to both the threads and the bearing face. Always follow the manufacturer's value where one exists.
M7 thread and dimensions
- Coarse thread
- M7×1 — pitch 1 mm
- Fine thread
- M7×0.75 — pitch 0.75 mm
- Tensile stress area Aₛ
- 28.9 mm² (coarse), 31.1 mm² (fine)
- Pitch diameter d₂
- 6.351 mm
- Tap drill
- 6 mm (coarse), 6.25 mm (fine)
- Wrench size (hex head)
- 11 mm
- Clearance hole
- 7.6 mm
How the M7 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 × 28.9 mm² = 12.9 kN
T = F × (0.16·P + 0.58·μ·d₂ + μ·Dₖₘ/2)
T = 12.9 kN × (0.16·1 + 0.58·0.15·6.35 + 0.15·9.30/2) mm = 17.9 N·m
Here d₂ is the pitch diameter and Dₖₘ the effective bearing diameter of the head (9.30 mm). Change the grade, lubrication or preload in the calculator below.
Frequently asked questions
What is the torque for an M7 8.8 bolt?
About 17.9 N·m (13.2 ft·lb) with dry threads, 13.4 N·m (9.88 ft·lb) with oiled threads and 8.90 N·m (6.57 ft·lb) with PTFE or moly paste, for a coarse M7×1 thread tightened to 70% of yield. The resulting clamp force is 12.9 kN.
What is the torque for an M7 10.9 bolt?
About 25.2 N·m (18.6 ft·lb) with dry threads, 18.8 N·m (13.9 ft·lb) with oiled threads and 12.5 N·m (9.23 ft·lb) with PTFE or moly paste, for a coarse M7×1 thread tightened to 70% of yield. The resulting clamp force is 18.2 kN.
What size wrench fits an M7 bolt?
A standard M7 hex head bolt or nut takes a 11 mm wrench or socket.
What drill size do I need to tap M7?
Use a 6 mm drill for M7×1 and 6.25 mm for M7×0.75.