7/16-14 tap drill size
Use a U drill (0.3680 in) for a 7/16-14 cutting tap at 75% thread.
| Tap type | Drill | Decimal (in) |
|---|---|---|
| Cutting tap, 75% thread | U | 0.3680 |
| Cutting tap, 50% thread (hard material) | 25/64" | 0.3906 |
| Roll / form tap, 65% thread | 13/32 | 0.4063 |
| Helicoil / STI insert (7/16-14×1D) | 29/64" | 0.4531 |
- Pitch
- 1.8143 mm (14 TPI)
- Major Ø
- 0.4375
- Pitch Ø
- 0.3911
- Minor Ø
- 0.3499
Common questions
- What size drill for a 7/16-14 tap?
- Use a U drill (0.3680 in) for a 7/16-14 cutting tap at 75% thread.
- What drill for a 7/16-14 roll (form) tap?
- About 0.4059 in; the nearest standard drill is 13/32. Check your tap maker's table.
- What drill for a 7/16-14 Helicoil?
- Drill 29/64" (0.4531 in), then tap with the 7/16-14 STI tap.
Other UNC sizes
Drill sizes from Machinery's Handbook and ASME B1.1/B1.13M; roll tap sizes from the form-tap formula. Tap and insert makers' tables are authoritative.