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Woodruff Key Spec Table
Woodruff Key Specifications — 24 sizes
KS B 1311ISO 3912JIS B 1301DIN 6888
A semicircular (Woodruff) key for torque transmission on shaft ends or tapered shafts. Offers simple keyway machining.
Practical Notes
- Not suitable for high torque. Use parallel keys or splines for heavy-duty torque transmission.
- Single milling cutter pass for keyway — low machining cost. Suitable for light-load applications like small pumps and distributor shafts.
Selection Guide
Semicircular key for light-duty torque on tapered or shaft ends. Shallow keyway minimizes shaft weakening; simple machining. Not suitable for high torque. Used in automotive distributors, small pumps, etc.
Woodruff KeyKSISOJISDINWoodruff Key
6 sizesThe dimensions below are identical across KS B 1311 · ISO 3912 · JIS B 1301 · DIN 6888.
| Nominal | b | h | Shaft Dia | Standard | - |
|---|---|---|---|---|---|
| 2×6.5 | 2 | - | 6~8 | KS B 1311 | - |
| 2.5×9 | 2.5 | - | 8~10 | KS B 1311 | - |
| 3×10 | 3 | - | 10~12 | KS B 1311 | - |
| 4×13 | 4 | - | 12~17 | KS B 1311 | - |
| 5×16 | 5 | - | 17~22 | KS B 1311 | - |
| 6×19 | 6 | - | 22~30 | KS B 1311 | - |
Key Features
- Semicircular cross-section fits into shallow Woodruff keyway; suited for tapered shafts
- KS B 1313 / DIN 6888; key number (e.g., 4×6.5) specifies width × diameter
- Shallow shaft keyway minimizes cross-section weakening; for light-duty torque only
Key Applications
Automotive distributor shafts, small pump shafts, power tool gear shafts, tapered shaft pulleys, instrument drive shafts
FAQ
Why are Woodruff keys used on tapered shafts?
Semicircular keys self-align in shaft keyways, staying stable on tapered surfaces. Shallow keyway minimizes shaft weakening, and end-of-shaft assembly is easy.