What torque does an M10 × 1.5 bolt take?

How it is worked out

1. Torque is only a proxy for tensionT = K × D × F
2. Tensile stress area of this bolt57.99 mm²
3. Target 75% of proof load25.23 kN of clamp force in Class 8.8
4. Multiply out0.20 × 0.01 m × 25,225 N = 50.5 N·m

T = K · D · F — and 85–90% of that torque is spent on friction

Worth knowing

Dry, as received — K 0.20

Class 8.8 50.5 N·m (37.2 lb·ft) · Class 10.9 72.2 N·m (53.2 lb·ft) · Class 12.9 84.4 N·m (62.2 lb·ft) · A2-70 stainless 39.1 N·m (28.9 lb·ft)

Lightly oiled — K 0.15

Class 8.8 37.8 N·m · Class 10.9 54.1 N·m · Class 12.9 63.3 N·m · A2-70 stainless 29.4 N·m

Anti-seize or moly — K 0.12

Class 8.8 30.3 N·m · Class 10.9 43.3 N·m · Class 12.9 50.6 N·m · A2-70 stainless 23.5 N·m

Why lubrication changes it so violently

Almost all the torque goes into friction rather than tension. Halving the friction roughly doubles the preload for the same torque — which is how a bolt gets snapped with a correctly set wrench and a dry-torque chart.

Single shear capacity

27.8 kN in Class 8.8

Can it be reused

At 75% of proof, yes — the bolt stayed elastic. Torque-to-yield fasteners have already stretched permanently and cannot.

The thread it goes into

This sizes the bolt, not the hole. A steel bolt in aluminium strips the aluminium first unless engagement is one and a half diameters or more.

Every grade at this size

Nearby sizes

Do it with your own numbers

This page answers one specific question. The Bolt Torque Calculator takes any values you like and answers as you type — in your browser, so nothing you enter is sent anywhere.