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Thread Pitch & Tap Chart
Comprehensive reference for metric and imperial thread specifications and tap drill sizes
Metric Threads (ISO)
| Thread Size | Pitch (mm) | Tap Drill (mm) | Decimal (in) |
|---|---|---|---|
| M1.6 | 0.35 | 1.25 | 0.0492 |
| M2 | 0.4 | 1.6 | 0.0630 |
| M2.5 | 0.45 | 2.05 | 0.0807 |
| M3 | 0.5 | 2.5 | 0.0984 |
| M4 | 0.7 | 3.3 | 0.1299 |
| M5 | 0.8 | 4.2 | 0.1654 |
| M6 | 1 | 5 | 0.1969 |
| M8 | 1.25 | 6.8 | 0.2677 |
| M10 | 1.5 | 8.5 | 0.3346 |
| M12 | 1.75 | 10.2 | 0.4016 |
| M14 | 2 | 12 | 0.4724 |
| M16 | 2 | 14 | 0.5512 |
| M18 | 2.5 | 15.5 | 0.6102 |
| M20 | 2.5 | 17.5 | 0.6890 |
| M22 | 2.5 | 19.5 | 0.7677 |
| M24 | 3 | 21 | 0.8268 |
| M27 | 3 | 24 | 0.9449 |
| M30 | 3.5 | 26.5 | 1.0433 |
Imperial Threads (UNC/UNF)
| Thread Size | TPI | Tap Drill (in) | Drill Size |
|---|---|---|---|
| #4-40 | 40 | 0.089 | #43 |
| #6-32 | 32 | 0.106 | #36 |
| #8-32 | 32 | 0.136 | #29 |
| #10-24 | 24 | 0.149 | #25 |
| #12-24 | 24 | 0.173 | #16 |
| 1/4-20 | 20 | 0.201 | #7 |
| 5/16-18 | 18 | 0.257 | F |
| 3/8-16 | 16 | 0.313 | 5/16 |
| 7/16-14 | 14 | 0.368 | U |
| 1/2-13 | 13 | 0.422 | 27/64 |
| 9/16-12 | 12 | 0.484 | 31/64 |
| 5/8-11 | 11 | 0.531 | 17/32 |
| 3/4-10 | 10 | 0.656 | 21/32 |
| 7/8-9 | 9 | 0.766 | 49/64 |
| 1-8 | 8 | 0.875 | 7/8 |