The data chart below shows the standard metric ‘coarse’ threads and their drill holes sizes were are most commonly used when tapping sheet metal fabrications.
| METRIC COARSE THREAD SIZES in mm | |
| Tap Size | Drill size |
| M2 x 0.4 | 1.6 |
| M2.5 x 0.45 | 2.05 |
| M3 x 0.5 | 2.5 |
| M3.5 x 0.6 | 2.9 |
| M4 x 0.7 | 3.3 |
| M4.5 x 0.75 | 3.7 |
| M5 x 0.8 | 4.2 |
| M6 x 1.0 | 5.0 |
| M7 x 1.0 | 6.0 |
| M8 x 1.25 | 6.8 |
| M9 x 1.25 | 7.8 |
| M10 x 1.5 | 8.5 |
| M11 x 1.5 | 9.5 |
| M12 x 1.75 | 10.2 |
| M14 x 2.0 | 12 |
| M16 x 2.0 | 14 |
| M18 x 2.5 | 15.5 |
| M20 x 2.5 | 17.5 |
