Tap Drill for Machine Screws (in)
- This chart show what size drill bit to use with a tap.
- Drill size recommendations are for 70-75% thread height.
- Drills produce a hole slightly larger then their normal size.
Tap Drill for Machine Screws (in) Datasheet
| Pipe
Size | Threads
per Inch | Drill
Size | Drill
Size Decimal |
|---|---|---|---|
| 1/4 | 20 | 7 | 0.2010 |
| 1/4 | 28 | 3 | 0.2130 |
| 5/16 | 18 | F | 0.2570 |
| 5/16 | 24 | I | 0.2720 |
| 3/8 | 16 | 5/16 | 0.3125 |
| 3/8 | -24 | Q | 0.3320 |
| 7/16 | 14 | U | 0.3680 |
| 7/16 | 20 | 25/64 | 0.3906 |
| 1/2 | 13 | 27/64 | 0.4219 |
| 1/2 | 20 | 29/64 | 0.4531 |
| 9/16 | 12 | 31/64 | 0.4844 |
| 9/16 | 18 | 33/64 | 0.5156 |
| 5/8 | 11 | 17/32 | 0.5312 |
| 5/8 | 18 | 37/64 | 0.5781 |
| 3/4 | 10 | 21/32 | 0.6562 |
| 3/4 | 16 | 11/16 | 0.6875 |
| 7/8 | 9 | 49/64 | 0.7656 |
| 7/8 | 14 | 13/16 | 0.8125 |
| 1 | 8 | 7/8 | 0.8750 |
| 1 | 12 | 59/64 | 0.9219 |
| 1-1/8 | 7 | 63/64 | 0.9844 |
| 1-1/8 | 12 | 1-3/64 | 1.0469 |
| 1-1/4 | 7 | 1-7/64 | 1.1094 |
| 1-1/4 | 12 | 1-11/64 | 1.1719 |
| 1-3/8 | 6 | 1-11/32 | 1.2188 |
| 1-3/8 | 12 | 1-19/64 | 1.2969 |
| 1-1/2 | 6 | 1-11/32 | 1.3438 |
| 1-1/2 | 12 | 1-27/64 | 1.4219 |
| Pipe Size | Threads
per Inch | Drill Size | Drill Size
Decimal |