Key & Keyway Sizing Calculator

Check shear stress on a parallel key transmitting shaft torque.

Transmitted torque T (N·m)Shaft diameter d (mm)Key width w (mm)Key length L (mm)Allowable shear stress (MPa)Calculate

Equations

Tangential force F = 2000T/d. Key shear stress τ = F/(w·L).

Assumptions

Force acts at the shaft surface; uniform shear across the key cross-section; static loading only.