8-36 tap drill size
Use a #29 drill (0.1360 in) for a 8-36 cutting tap at 75% thread.
| Tap type | Drill | Decimal (in) |
|---|---|---|
| Cutting tap, 75% thread | #29 | 0.1360 |
| Cutting tap, 50% thread (hard material) | #26 | 0.1470 |
| Roll / form tap, 65% thread | #24 | 0.1520 |
| Helicoil / STI insert (#8-36×1D) | #13 | 0.1850 |
- Pitch
- 0.7056 mm (36 TPI)
- Major Ø
- 0.1640
- Pitch Ø
- 0.1460
- Minor Ø
- 0.1299
8-36 tapping speeds and feeds
Feed = pitch (0.0278 in per rev). Starting points for a general-purpose HSS cut tap:
- Aluminum 6061 / 7075: 1,630 RPM · 45.3 IPM
- Free-machining / mild steel: 470 RPM · 13.1 IPM
- 304 / 316 stainless: 230 RPM · 6.39 IPM
8-36 tap speeds and feeds: all materials, form taps and G84 code · #29 drill size and speeds
Common questions
- What size drill for a 8-36 tap?
- Use a #29 drill (0.1360 in) for a 8-36 cutting tap at 75% thread.
- What drill for a 8-36 roll (form) tap?
- About 0.1517 in; the nearest standard drill is #24. Check your tap maker's table.
- What drill for a 8-36 Helicoil?
- Drill #13 (0.1850 in), then tap with the 8-36 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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