Friction coefficient — resistance between threads and bearing surfaces. Higher friction requires more torque for same preload. Example: 0.15 for dry steel.

Friction is required

Nominal bolt diameter (m) — larger diameter increases torque for same clamp force. Example: 0.010 m (10 mm) for M10 bolt.

Diameter is required

Clamp force (N) — desired preload. Higher force increases torque linearly. Example: 20000 N for structural joint.

Clamp Force is required