| Thread Size | Thread Pitch (mm) | Tapping Diameter | ||
| Coarse | Fine | Coarse | Fine | |
| M1.6 | 0.35 | - | 1.25 | - |
| M2 | 0.4 | - | 1.6 | - |
| M2.5 | 0.45 | - | 2.05 | - |
| M3 | 0.5 | - | 2.5 | - |
| M4 | 0.7 | - | 3.3 | - |
| M5 | 0.8 | - | 4.2 | - |
| M6 | 1.0 | - | 5.0 | - |
| M8 | 1.25 | 1.0 | 6.8 | 7.0 |
| M10 | 1.5 | 1.25 | 8.5 | 8.7 |
| M12 | 1.75 | 1.25 | 10.2 | 10.8 |
| M16 | 2.0 | 1.5 | 14.0 | 14.5 |
| M20 | 2.5 | 1.5 | 17.5 | 18.5 |
| M24 | 3.0 | 2.0 | 21.0 | 22.0 |
| M30 | 3.5 | 2.0 | 26.5 | 28.0 |
| M36 | 4.0 | 3.0 | 32.0 | 33.0 |
UNC / UNF ThreadsUnified National Coarse and Unified National Fine thread sizes, threads per inch, pitches and required tapping drill size. |
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