KEVOS® MAKEOS · Fasteners
Taper Pin for Torque Transmission
What mean diameter of taper pin through this shaft and hub transmits the torque safely?
Mean taper pin diameter needed to transmit a torque (or power at a speed) through a shaft by double shear, by the handbook formula, with the shear stress in a chosen pin.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Load given as | choice | Enter the torque directly, or power and speed. |
| Torque | N·m | Torque to transmit (torque mode). |
| Power | kW | Power transmitted (power mode). |
| Speed | rpm | Shaft speed (power mode). |
| Shaft diameter | mm | Shaft diameter at the pin. |
| Safe shear stress of the pin | MPa | Safe shear stress for the pin material (with your safety margin). |
| Pin mean diameter to check (0 = none) | mm | Mean diameter of a proposed pin. |
Method and formulas
- d = 1.13 √(T ÷ (D S)) with T in N·mm, D in mm and S in N/mm² (the pin is in double shear at the shaft surface).
- Torque from power: T = 9549 × P ÷ n (N·m).
- Check: the force at the shaft surface, 2T ÷ D, is carried by two pin sections, so τ = 4T ÷ (π d² D).
- Example: 60 N·m through a 30 mm shaft needs a 5.65 mm mean-diameter pin.
Limitations
- Pin shear only; the cross hole weakens the shaft and the hub bearing stress must be checked.
- Use a safe stress with a margin for shock.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Size a cross pin fixing a hub or collar to a shaft
- Check an existing pin after a power change
- Choose between a pin and a key
Who it is for
- Design engineers
- Maintenance fitters
What you get
- Mean pin diameter needed
- Shear stress in the checked pin
Interpreting the result
- Taper pins are good for light to moderate torque; use keys or splines for heavy drives.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 220, 1714–1720. Topic reference; no source tables or recommended settings are reproduced.
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