Shaft Size Calculator

Your details

Choose how the shaft is loaded. Most drives use "Torque only" or "Combined bending and torsion". Rigidity mode sizes the shaft to limit deflection rather than stress.
The torsional load on the shaft. Used in all modes except "Bending only".
N·m
Presets fill the allowable shear stress field. Choose "Custom" to enter your own value.
Maximum permissible shear stress for the material and service. Presets use mid-range values; enter your own for the actual grade.
MPa
Multiplies the effective stress to leave a margin for load uncertainties, surface finish and stress concentrations.
Minimum shaft diameterWell within safety margin
42.43

The smallest diameter that satisfies the design criterion

Torque used in calculation500
Shear stress at min diameter33.33
Margin of safety0.5%
0.5% ratio
Overstressed<0At limit0-0.1Safe margin0.1-0.5Well within limits0.5+

Minimum shaft diameter: 42.43 mm

  • The minimum required shaft diameter is 42.43 mm. Always select the next standard size up to ensure a safe design.
  • The actual shear stress at this diameter is 50 percent below the allowable limit, giving a margin above the applied safety factor.

Next stepRound up to the nearest standard shaft diameter (ISO 286 for metric, ANSI B4.1 for imperial). Check keyway depth, fillet radii, and bearing fits against the selected diameter.

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