Solid circular shaft torsion

Relates torque, selected allowable shear stress and diameter for a solid circular shaft under pure torsion.

VERIFIED FORMULA RECORD

T = πτd³ / 16

Relates torque, selected allowable shear stress and diameter for a solid circular shaft under pure torsion.

Machine DesignVerifiedReviewed 2026-08-09

Variables and units

T = torque (N·mm)

τ = selected allowable shear stress (N/mm²)

d = shaft diameter (mm)

Conditions and limitations

  • Solid circular shaft
  • Pure torsion
  • Selected allowable stress is source-controlled

Source: J. E. Shigley et al., Mechanical Engineering Design, torsion of circular shafts.

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