1. Origin of the Standard
The taper bush (also called taper lock bush) is a standardized component that uses a tapered fit to achieve a removable connection between a shaft and a hub (such as pulleys, sprockets, or couplings).
- Origin: First developed and promoted by Fenner (UK) in the mid-20th century.
- Standard nature: Initially a company/industry standard, not an official national standard (such as GB, DIN, or ANSI).
- Adoption: Due to its compact design, easy installation/removal, and interchangeability, it quickly spread across Europe, the US, Japan, and China.
- Current status: The commonly used models (e.g., 1008, 1210, 1610, 3020, 5050) are all derived from the Fenner series and have become a de facto international industry standard.
2. Common Taper Bush Models (Metric Parameters)
| Model | Shaft Diameter Range (mm) | Outer Diameter (mm) | Taper | Typical Application |
|---|---|---|---|---|
| 1008 | 9 – 25 | ≈25 | 1:12 | Small pulleys, sprockets |
| 1108 | 9 – 28 | ≈28 | 1:12 | Small pulleys, couplings |
| 1210 | 10 – 32 | ≈30 | 1:12 | Medium pulleys |
| 1610 | 14 – 42 | ≈40 | 1:12 | Sprockets, timing pulleys |
| 1615 | 14 – 42 | ≈40 | 1:12 | Wider hubs |
| 2012 | 19 – 50 | ≈50 | 1:12 | Motor pulleys |
| 2517 | 20 – 65 | ≈63 | 1:12 | Heavy-duty pulleys, couplings |
| 3020 | 25 – 75 | ≈76 | 1:12 | Heavy-duty transmission |
| 3030 | 25 – 75 | ≈76 | 1:12 | Wide hub components |
| 3525 | 35 – 90 | ≈89 | 1:12 | Medium-to-large machinery |
| 3535 | 35 – 90 | ≈89 | 1:12 | Wide hub, heavy load |
| 4040 | 40 – 100 | ≈102 | 1:12 | High-power sprockets/pulleys |
| 5050 | 50 – 125 | ≈127 | 1:12 | Mining, fans, heavy-duty machinery |
Key Features:
- All models use a 1:12 taper for universal interchangeability.
- The same model from different manufacturers is generally interchangeable.
3. Model Numbering System
Each taper bush model is composed of four digits:
- First two digits = outer diameter in inches × 10
- Last two digits = length in inches × 10
Examples:
- 1008 → Outer diameter 1.0 inch (≈25.4 mm), length 0.8 inch (≈20.3 mm).
- 3020 → Outer diameter 3.0 inches (≈76.2 mm), length 2.0 inches (≈50.8 mm).
4. Inch-to-Metric Conversion Table
| Model | Outer Diameter (inches) | Length (inches) | Outer Diameter (mm) | Length (mm) |
|---|---|---|---|---|
| 1008 | 1.0″ | 0.8″ | 25.4 | 20.3 |
| 1108 | 1.1″ | 0.8″ | 27.9 | 20.3 |
| 1210 | 1.2″ | 1.0″ | 30.5 | 25.4 |
| 1610 | 1.6″ | 1.0″ | 40.6 | 25.4 |
| 1615 | 1.6″ | 1.5″ | 40.6 | 38.1 |
| 2012 | 2.0″ | 1.2″ | 50.8 | 30.5 |
| 2517 | 2.5″ | 1.7″ | 63.5 | 43.2 |
| 3020 | 3.0″ | 2.0″ | 76.2 | 50.8 |
| 3030 | 3.0″ | 3.0″ | 76.2 | 76.2 |
| 3525 | 3.5″ | 2.5″ | 88.9 | 63.5 |
| 3535 | 3.5″ | 3.5″ | 88.9 | 88.9 |
| 4040 | 4.0″ | 4.0″ | 101.6 | 101.6 |
| 5050 | 5.0″ | 5.0″ | 127.0 | 127.0 |
5. Conclusion
- The taper bush system is not an official national standard, but rather a UK Fenner-developed industry standard that became globally adopted.
- Model numbering rules are simple and consistent, ensuring interchangeability worldwide.
- In international sourcing and technical communication, confirming the model number (e.g., 1210, 3020) is usually enough to ensure compatibility.
