Complete reference for metric and imperial tap drill sizes. Find the correct drill bit size for perfect thread tapping in your CNC machining projects.
| Thread Size | Tap Drill Size | Decimal (in) | Type |
|---|---|---|---|
| M3 x 0.5 | 2.50 | 0.0984 | Metric |
| M4 x 0.7 | 3.30 | 0.1299 | Metric |
| M5 x 0.8 | 4.20 | 0.1654 | Metric |
| M6 x 1.0 | 5.00 | 0.1969 | Metric |
| M8 x 1.25 | 6.75 | 0.2656 | Metric |
| M10 x 1.5 | 8.50 | 0.3346 | Metric |
| M12 x 1.75 | 10.25 | 0.4035 | Metric |
| M14 x 2.0 | 12.00 | 0.4724 | Metric |
| M16 x 2.0 | 14.00 | 0.5512 | Metric |
| M20 x 2.5 | 17.50 | 0.6890 | Metric |
| #4-40 | #43 | 0.0890 | Imperial |
| #6-32 | #36 | 0.1065 | Imperial |
| #8-32 | #29 | 0.1360 | Imperial |
| #10-24 | #25 | 0.1495 | Imperial |
| #10-32 | #21 | 0.1590 | Imperial |
| 1/4"-20 | #7 | 0.2010 | Imperial |
| 1/4"-28 | #3 | 0.2130 | Imperial |
| 5/16"-18 | F | 0.2570 | Imperial |
| 5/16"-24 | I | 0.2720 | Imperial |
| 3/8"-16 | 5/16" | 0.3125 | Imperial |
| 3/8"-24 | Q | 0.3320 | Imperial |
| 7/16"-14 | U | 0.3680 | Imperial |
| 1/2"-13 | 27/64" | 0.4219 | Imperial |
| 1/2"-20 | 29/64" | 0.4531 | Imperial |
| 9/16"-12 | 31/64" | 0.4844 | Imperial |
| 5/8"-11 | 17/32" | 0.5312 | Imperial |
| 3/4"-10 | 21/32" | 0.6562 | Imperial |
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