The table below shows IT (International Tolerance) dimensional tolerance values achievable with different manufacturing techniques. Each machining method operates within a specific tolerance range. A lower IT value means tighter tolerance.
| Machining Method | IT 4 | IT 5 | IT 6 | IT 7 | IT 8 | IT 9 | IT 10 | IT 11 | IT 12 | IT 13 |
|---|---|---|---|---|---|---|---|---|---|---|
| Lapping - Honing | ■ | ■ | ||||||||
| Cylindrical Grinding | ■ | ■ | ■ | |||||||
| Surface Grinding | ■ | ■ | ■ | ■ | ||||||
| Diamond Turning | ■ | ■ | ■ | |||||||
| Diamond Boring | ■ | ■ | ■ | |||||||
| Broaching | ■ | ■ | ■ | ■ | ||||||
| Reaming | ■ | ■ | ■ | ■ | ■ | |||||
| Turning | ■ | ■ | ■ | ■ | ■ | ■ | ■ | |||
| Boring | ■ | ■ | ■ | ■ | ■ | ■ | ||||
| Milling | ■ | ■ | ■ | ■ | ||||||
| Planing | ■ | ■ | ■ | ■ | ||||||
| Drilling | ■ | ■ | ■ | ■ |
■ = tolerance range achievable with this method. Each method in the table can achieve tolerances in the corresponding IT class.
About Tolerance Classes
- IT 4-5: Very tight tolerances. Achieved by lapping, honing and precision grinding.
- IT 6-7: Precision tolerances. Achieved by grinding, reaming, diamond turning. Commonly used in machine manufacturing.
- IT 8-9: Medium precision. Achieved by turning, boring operations.
- IT 10-13: General tolerances. Achieved by machining methods like milling, planing, drilling.
Related Articles
- Hole and Shaft Tolerances — Information about hole shaft tolerances, tolerance tables and fits.
- Surface Roughness Chart — Ra roughness values by manufacturing method.
Translated by: Yamac Aksan. Source: Engineering Toolbox