Metric tap drill chart
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Tap drill (chart, about 75–80% thread), drill for 65% (stainless/tough materials), and ISO 273 clearance holes in mm.
Metric coarse
| Size | Pitch | Tap drill | 65% drill | Clearance fine / med / coarse |
|---|---|---|---|---|
| M1.6 | 0.35 | 1.25 | 1.3 | 1.7 / 1.8 / 2 |
| M2 | 0.4 | 1.6 | 1.65 | 2.2 / 2.4 / 2.6 |
| M2.5 | 0.45 | 2.05 | 2.1 | 2.7 / 2.9 / 3.1 |
| M3 | 0.5 | 2.5 | 2.6 | 3.2 / 3.4 / 3.6 |
| M3.5 | 0.6 | 2.9 | 3 | 3.7 / 3.9 / 4.2 |
| M4 | 0.7 | 3.3 | 3.4 | 4.3 / 4.5 / 4.8 |
| M5 | 0.8 | 4.2 | 4.3 | 5.3 / 5.5 / 5.8 |
| M6 | 1 | 5 | 5.2 | 6.4 / 6.6 / 7 |
| M8 | 1.25 | 6.8 | 6.9 | 8.4 / 9 / 10 |
| M10 | 1.5 | 8.5 | 8.7 | 10.5 / 11 / 12 |
| M12 | 1.75 | 10.2 | 10.5 | 13 / 13.5 / 14.5 |
| M14 | 2 | 12 | 12.3 | 15 / 15.5 / 16.5 |
| M16 | 2 | 14 | 14.25 | 17 / 17.5 / 18.5 |
| M18 | 2.5 | 15.5 | 16 | 19 / 20 / 21 |
| M20 | 2.5 | 17.5 | 18 | 21 / 22 / 24 |
| M22 | 2.5 | 19.5 | 20 | 23 / 24 / 26 |
| M24 | 3 | 21 | 21.5 | 25 / 26 / 28 |
| M27 | 3 | 24 | 24.5 | 28 / 30 / 32 |
| M30 | 3.5 | 26.5 | 27 | 31 / 33 / 35 |
| M33 | 3.5 | 29.5 | 30 | 34 / 36 / 38 |
| M36 | 4 | 32 | 32.5 | 37 / 39 / 42 |
| M42 | 4.5 | 37.5 | 38.25 | 43 / 45 / 48 |
| M48 | 5 | 43 | 44 | 50 / 52 / 56 |
Metric fine
| Size | Pitch | Tap drill (D − P) | Thread % |
|---|---|---|---|
| M8 × 1 | 1 | 7 | 77% |
| M10 × 1.25 | 1.25 | 8.75 | 77% |
| M10 × 1 | 1 | 9 | 77% |
| M12 × 1.5 | 1.5 | 10.5 | 77% |
| M12 × 1.25 | 1.25 | 10.75 | 77% |
| M14 × 1.5 | 1.5 | 12.5 | 77% |
| M16 × 1.5 | 1.5 | 14.5 | 77% |
| M18 × 1.5 | 1.5 | 16.5 | 77% |
| M20 × 1.5 | 1.5 | 18.5 | 77% |
| M22 × 1.5 | 1.5 | 20.5 | 77% |
| M24 × 2 | 2 | 22 | 77% |
| M27 × 2 | 2 | 25 | 77% |
| M30 × 2 | 2 | 28 | 77% |
| M36 × 3 | 3 | 33 | 77% |
lathecalculator.co.uk – free to print and share for personal/workshop use. Values are for reference only – check against your tooling maker’s data.