M1.6 Bolt Torque
An M1.6 8.8 bolt with a coarse M1.6×0.35 thread needs about 0.20 N·m (0.15 ft·lb) when dry and 0.15 N·m (0.11 ft·lb) when oiled, tightened to 70% of yield (clamp force 0.57 kN).
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 0.21 kN48 lbf | 0.08 N·m0.06 ft·lb | 0.06 N·m0.04 ft·lb | 0.04 N·m0.03 ft·lb |
| 4.8 | 0.28 kN64 lbf | 0.10 N·m0.07 ft·lb | 0.08 N·m0.06 ft·lb | 0.05 N·m0.04 ft·lb |
| 5.6 | 0.27 kN60 lbf | 0.10 N·m0.07 ft·lb | 0.07 N·m0.05 ft·lb | 0.05 N·m0.04 ft·lb |
| 5.8 | 0.36 kN80 lbf | 0.13 N·m0.09 ft·lb | 0.10 N·m0.07 ft·lb | 0.07 N·m0.05 ft·lb |
| 6.8 | 0.43 kN96 lbf | 0.15 N·m0.11 ft·lb | 0.12 N·m0.09 ft·lb | 0.08 N·m0.06 ft·lb |
| 8.8 | 0.57 kN128 lbf | 0.20 N·m0.15 ft·lb | 0.15 N·m0.11 ft·lb | 0.11 N·m0.08 ft·lb |
| 9.8 | 0.64 kN144 lbf | 0.23 N·m0.17 ft·lb | 0.17 N·m0.13 ft·lb | 0.12 N·m0.09 ft·lb |
| 10.9 | 0.80 kN180 lbf | 0.29 N·m0.21 ft·lb | 0.22 N·m0.16 ft·lb | 0.15 N·m0.11 ft·lb |
| 12.9 | 0.96 kN216 lbf | 0.34 N·m0.25 ft·lb | 0.26 N·m0.19 ft·lb | 0.18 N·m0.13 ft·lb |
| A2-70 | 0.40 kN90 lbf | 0.14 N·m0.11 ft·lb | 0.11 N·m0.08 ft·lb | 0.07 N·m0.05 ft·lb |
| A4-70 | 0.40 kN90 lbf | 0.14 N·m0.11 ft·lb | 0.11 N·m0.08 ft·lb | 0.07 N·m0.05 ft·lb |
| A4-80 | 0.53 kN120 lbf | 0.19 N·m0.14 ft·lb | 0.14 N·m0.11 ft·lb | 0.10 N·m0.07 ft·lb |
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| 4.6 | 0.26 kN59 lbf | 0.09 N·m0.07 ft·lb | 0.07 N·m0.05 ft·lb | 0.04 N·m0.03 ft·lb |
| 4.8 | 0.35 kN79 lbf | 0.12 N·m0.09 ft·lb | 0.09 N·m0.07 ft·lb | 0.06 N·m0.04 ft·lb |
| 5.6 | 0.33 kN74 lbf | 0.11 N·m0.08 ft·lb | 0.08 N·m0.06 ft·lb | 0.05 N·m0.04 ft·lb |
| 5.8 | 0.44 kN99 lbf | 0.15 N·m0.11 ft·lb | 0.11 N·m0.08 ft·lb | 0.07 N·m0.05 ft·lb |
| 6.8 | 0.53 kN118 lbf | 0.18 N·m0.13 ft·lb | 0.13 N·m0.10 ft·lb | 0.09 N·m0.06 ft·lb |
| 8.8 | 0.70 kN158 lbf | 0.24 N·m0.18 ft·lb | 0.18 N·m0.13 ft·lb | 0.12 N·m0.09 ft·lb |
| 9.8 | 0.79 kN178 lbf | 0.27 N·m0.20 ft·lb | 0.20 N·m0.15 ft·lb | 0.13 N·m0.10 ft·lb |
| 10.9 | 0.99 kN222 lbf | 0.34 N·m0.25 ft·lb | 0.25 N·m0.18 ft·lb | 0.16 N·m0.12 ft·lb |
| 12.9 | 1.18 kN266 lbf | 0.40 N·m0.30 ft·lb | 0.30 N·m0.22 ft·lb | 0.20 N·m0.14 ft·lb |
| A2-70 | 0.49 kN111 lbf | 0.17 N·m0.12 ft·lb | 0.12 N·m0.09 ft·lb | 0.08 N·m0.06 ft·lb |
| A4-70 | 0.49 kN111 lbf | 0.17 N·m0.12 ft·lb | 0.12 N·m0.09 ft·lb | 0.08 N·m0.06 ft·lb |
| A4-80 | 0.66 kN148 lbf | 0.22 N·m0.17 ft·lb | 0.17 N·m0.12 ft·lb | 0.11 N·m0.08 ft·lb |
Torque for M1.6 hex head bolts and nuts, standard ISO/ASME heads on steel with a 1.8 mm clearance hole. Friction μ applies to both the threads and the bearing face. Always follow the manufacturer's value where one exists.
M1.6 thread and dimensions
- Coarse thread
- M1.6×0.35 — pitch 0.35 mm
- Fine thread
- M1.6×0.2 — pitch 0.2 mm
- Tensile stress area Aₛ
- 1.27 mm² (coarse), 1.57 mm² (fine)
- Pitch diameter d₂
- 1.373 mm
- Tap drill
- 1.25 mm (coarse), 1.4 mm (fine)
- Wrench size (hex head)
- 3.2 mm
- Clearance hole
- 1.8 mm
How the M1.6 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 × 1.27 mm² = 0.57 kN
T = F × (0.16·P + 0.58·μ·d₂ + μ·Dₖₘ/2)
T = 0.57 kN × (0.16·0.35 + 0.58·0.15·1.37 + 0.15·2.50/2) mm = 0.20 N·m
Here d₂ is the pitch diameter and Dₖₘ the effective bearing diameter of the head (2.50 mm). Change the grade, lubrication or preload in the calculator below.
Frequently asked questions
What is the torque for an M1.6 8.8 bolt?
About 0.20 N·m (0.15 ft·lb) with dry threads, 0.15 N·m (0.11 ft·lb) with oiled threads and 0.11 N·m (0.08 ft·lb) with PTFE or moly paste, for a coarse M1.6×0.35 thread tightened to 70% of yield. The resulting clamp force is 0.57 kN.
What is the torque for an M1.6 10.9 bolt?
About 0.29 N·m (0.21 ft·lb) with dry threads, 0.22 N·m (0.16 ft·lb) with oiled threads and 0.15 N·m (0.11 ft·lb) with PTFE or moly paste, for a coarse M1.6×0.35 thread tightened to 70% of yield. The resulting clamp force is 0.80 kN.
What size wrench fits an M1.6 bolt?
A standard M1.6 hex head bolt or nut takes a 3.2 mm wrench or socket.
What drill size do I need to tap M1.6?
Use a 1.25 mm drill for M1.6×0.35 and 1.4 mm for M1.6×0.2.