Torsion Spring Constant Calculator and Formula

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This calculator will determine the spring rate related to a torsion spring from basic geometry and material data input. Default units are shown in inches, etc however SI (metric) can be used.

Torsion Spring

This equation will determine the spring constant required to change the angle of each spring contacting leg to another.

Equation: k = P*M/Deg


P = Force exerted on spring (lbs)
M = Moment arm (inch)
Deg =Deflection in (degrees)
k = Spring constant (in-lbs/Deg)

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Torsion Spring Constant Calculator

Torsion Spring Constant Design Considerations:

As load is applied to a torsion spring, the springs diameter will decrease, reducing the outside and inside diameters. The spring will also grow in length. In most cases is it wise to design for a torsion spring to wind in the direction of the coil winding. Should design require that the torsion spring wind in the unwinding direction, maximum load should be and degrees of wind should be lowered. Normally, torsion spring are designed about a shaft or mandrel. The shaft will ensure spring stability and location. Allow for 10% clearance between the torsion spring and the shaft with spring at maximum deflection.