1-72 tap drill size
Use a #53 drill (0.0595 in) for a 1-72 cutting tap at 75% thread.
| Tap type | Drill | Decimal (in) |
|---|---|---|
| Cutting tap, 75% thread | #53 | 0.0595 |
| Cutting tap, 50% thread (hard material) | #52 | 0.0635 |
| Roll / form tap, 65% thread | #51 | 0.0670 |
| Helicoil / STI insert (#1-72×1D) | #45 | 0.0820 |
- Pitch
- 0.3528 mm (72 TPI)
- Major Ø
- 0.0730
- Pitch Ø
- 0.0640
- Minor Ø
- 0.0560
1-72 tapping speeds and feeds
Feed = pitch (0.0139 in per rev). Starting points for a general-purpose HSS cut tap:
- Aluminum 6061 / 7075: 3,660 RPM · 50.8 IPM
- Free-machining / mild steel: 1,050 RPM · 14.6 IPM
- 304 / 316 stainless: 520 RPM · 7.22 IPM
1-72 tap speeds and feeds: all materials, form taps and G84 code · #53 drill size and speeds
Common questions
- What size drill for a 1-72 tap?
- Use a #53 drill (0.0595 in) for a 1-72 cutting tap at 75% thread.
- What drill for a 1-72 roll (form) tap?
- About 0.0669 in; the nearest standard drill is #51. Check your tap maker's table.
- What drill for a 1-72 Helicoil?
- Drill #45 (0.0820 in), then tap with the 1-72 STI tap.
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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