Torsion Spring Calculator
Find the rate of a helical torsion spring.
A torsion spring resists twisting, storing energy as it winds up.
The math behind it
k = E·d⁴ ÷ (64·D·n), giving torque per radian of deflection.
Worked example
Steel, 2 mm wire, 15 mm coil, 6 coils → about 333 N·mm/rad.
FAQ
Why use Young's modulus, not shear?
Torsion springs bend their wire, so the bending modulus E applies.