Tap Drill Sizes (ISO 2306 (reference)) are a type of engineering reference used across industrial assembly. Below is the complete size table together with material, standard and application guidance.
About This Reference
This is an engineering reference table for tap drill sizes based on ISO 2306 (reference). Use it alongside our fastener catalog when selecting and specifying parts.
Reference Data (ISO 2306 (reference))
| Thread size | Pitch (mm) | Drill 75% thread (mm) | Drill 50% thread (mm) | Description |
|---|---|---|---|---|
| M1 | 0.25 | 0.75 | 0.8 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M1.2 | 0.25 | 0.95 | 1.0 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M1.4 | 0.3 | 1.1 | 1.15 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M1.6 | 0.35 | 1.25 | 1.3 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M1.8 | 0.35 | 1.45 | 1.5 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M2 | 0.4 | 1.6 | 1.65 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M2.5 | 0.45 | 2.05 | 2.1 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M3 | 0.5 | 2.5 | 2.55 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M3.5 | 0.6 | 2.9 | 2.95 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M4 | 0.7 | 3.3 | 3.4 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M4.5 | 0.75 | 3.7 | 3.8 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M5 | 0.8 | 4.2 | 4.3 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M6 | 1.0 | 5.0 | 5.1 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M7 | 1.0 | 6.0 | 6.1 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M8 | 1.25 | 6.8 | 6.9 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M8 | 1.0 | 7.0 | 7.1 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M9 | 1.25 | 7.8 | 7.9 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M10 | 1.5 | 8.5 | 8.7 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M10 | 1.25 | 8.8 | 8.9 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M11 | 1.5 | 9.5 | 9.7 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M12 | 1.75 | 10.2 | 10.4 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M12 | 1.5 | 10.5 | 10.7 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M14 | 2.0 | 12.0 | 12.2 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M14 | 1.5 | 12.5 | 12.7 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M16 | 2.0 | 14.0 | 14.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M16 | 1.5 | 14.5 | 14.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M18 | 2.5 | 15.5 | 15.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M18 | 1.5 | 16.5 | 16.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M20 | 2.5 | 17.5 | 17.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M20 | 1.5 | 18.5 | 18.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M22 | 2.5 | 19.5 | 19.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M22 | 1.5 | 20.5 | 20.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M24 | 3.0 | 21.0 | 21.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M24 | 2.0 | 22.0 | 22.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M27 | 3.0 | 24.0 | 24.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M30 | 3.5 | 26.5 | 26.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M30 | 2.0 | 28.0 | 28.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M33 | 3.5 | 29.5 | 29.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M36 | 4.0 | 32.0 | 32.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M39 | 4.0 | 35.0 | 35.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M42 | 4.5 | 37.5 | 37.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M45 | 4.5 | 40.5 | 40.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M48 | 5.0 | 43.0 | 43.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M52 | 5.0 | 47.0 | 47.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M56 | 5.5 | 50.5 | 50.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M60 | 5.5 | 54.5 | 54.75 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |
| M64 | 6.0 | 58.0 | 58.25 | Hand tapping: 75%; machine tapping 50% to reduce tool wear |