1-1/2-12 tap drill size
Use a 1-27/64 drill (1.4219 in) for a 1-1/2-12 cutting tap at 75% thread.
| Tap type | Drill | Decimal (in) |
|---|---|---|
| Cutting tap, 75% thread | 1-27/64 | 1.4219 |
| Cutting tap, 50% thread (hard material) | 1-29/64 | 1.4531 |
| Roll / form tap, 65% thread | 1-15/32 | 1.4688 |
- Pitch
- 2.1167 mm (12 TPI)
- Major Ø
- 1.5000
- Pitch Ø
- 1.4459
- Minor Ø
- 1.4098
Common questions
- What size drill for a 1-1/2-12 tap?
- Use a 1-27/64 drill (1.4219 in) for a 1-1/2-12 cutting tap at 75% thread.
- What drill for a 1-1/2-12 roll (form) tap?
- About 1.4632 in; the nearest standard drill is 1-15/32. Check your tap maker's table.
Other UNF 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.
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