Power Transmission Shaft Designer

Enter the power and speed a shaft must transmit, the allowable shear stress, and the shaft type. The app finds the torque, sizes the shaft for strength (and combined bending + torsion), checks a twist limit if you set one, picks the governing diameter, and back-checks the as-designed stress and angle of twist.

🆓 Free design tool — size as many shafts as you like · Balance … EP

① Power & speed

Transmitted power

Rotational speed (rpm)

② Shaft type & allowable stress

Cross-section

Diameter ratio k = d_inner / d_outer

Allowable shear stress τ_allow (MPa)

Bending moment M (N·m, optional)

Enter a bending moment only for a shaft that also bends (e.g. carries pulleys/gears). It is combined with the torque using the maximum-shear-stress theory (Tₑ = √(M² + T²)).

③ Twist limit (optional)

Also limit the angle of twist

Shear modulus G (GPa)

Shaft length L (mm)

Allowable twist φ_allow (°)

φ_allow is the total allowed twist over the whole length L (e.g. a common rule is ~1° per metre).

📐 Design result

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Required outer diameter (rounded up to a whole mm)

Torque T

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d from strength

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d from twist limit

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Polar moment J

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Actual shear τ

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Actual twist φ

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Stress utilization at the chosen diameter

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Power Transmission Shaft Designer

① Power & speed

② Shaft type & allowable stress

③ Twist limit (optional)

📐 Design result

Worked solution