Torsion Spring Calculator

Your details

Cross-sectional diameter of the spring wire. Measured with a micrometer on the bare wire.
in
Outside diameter of the wound coil. Mean diameter D = OD - wire diameter.
in
Number of coils that actually deflect under load. Does not include fixed end coils.
coils
Angular displacement applied to the free arm relative to the fixed arm.
deg
Wire alloy determines the modulus of elasticity (E) used in all spring calculations.
Spring rate (k)Stress too high
11.8313

Torque per degree of deflection

Torque (M)1,064.815
Inner-fiber stress (σ)11,825,278
Spring index (C)9
Mean coil diameter (D)0.9
Stress / tensile-strength ratio6,223.8%
6,223.8% of Su
Low stress (high-cycle safe)<35%Moderate (fatigue limit)35%-45%High (static loading only)45%-80%Over-stressed - redesign needed80%+

Spring rate is 11.8313 lb-in/deg, torque is 1064.815 lb-in at 90°.

  • Spring rate: 11.8313 lb-in/deg - the spring delivers 11.8313 lb-in/deg per degree of rotation.
  • Torque at 90 deg: 1064.815 lb-in.
  • Inner-fiber bending stress: 11825278 psi (6223.8% of approx. tensile strength).

Next stepStress exceeds 80% of approximate tensile strength. Reduce deflection, increase wire diameter, or switch to a higher-strength alloy.

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