M20x2 tap drill size
Use a 18.00 mm drill (18.00 mm) for a M20x2 cutting tap at 75% thread.
| Tap type | Drill | Decimal (mm) |
|---|---|---|
| Cutting tap, 75% thread | 18.00 mm | 18.00 |
| Cutting tap, 50% thread (hard material) | 18.75 mm | 18.75 |
| Roll / form tap, 65% thread | 19.0 mm | 19.00 |
- Pitch
- 2 mm
- Major Ø
- 20.00
- Pitch Ø
- 18.70
- Minor Ø
- 17.84
M20x2 tapping speeds and feeds
Feed = pitch (2 mm per rev). Starting points for a general-purpose HSS cut tap:
- Aluminum 6061 / 7075: 340 RPM · 680 mm/min
- Free-machining / mild steel: 100 RPM · 200 mm/min
- 304 / 316 stainless: 50 RPM · 100 mm/min
Tap speeds and feeds by size · 18.00 mm drill size and speeds
Common questions
- What size drill for a M20x2 tap?
- Use a 18.00 mm drill (18.00 mm) for a M20x2 cutting tap at 75% thread.
- What drill for a M20x2 roll (form) tap?
- About 19.12 mm; the nearest standard drill is 19.0 mm. Check your tap maker's table.
Other Metric fine 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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