M56x5.5 tap drill size
Use a 50.50 mm drill (50.50 mm) for a M56x5.5 cutting tap at 75% thread.
| Tap type | Drill | Decimal (mm) |
|---|---|---|
| Cutting tap, 75% thread | 50.50 mm | 50.50 |
| Cutting tap, 50% thread (hard material) | 52.5 mm | 52.50 |
| Roll / form tap, 65% thread | 53.5 mm | 53.50 |
- Pitch
- 5.5 mm
- Major Ø
- 56.00
- Pitch Ø
- 52.43
- Minor Ø
- 50.05
M56x5.5 tapping speeds and feeds
Feed = pitch (5.5 mm per rev). Starting points for a general-purpose HSS cut tap:
- Aluminum 6061 / 7075: 120 RPM · 660 mm/min
- Free-machining / mild steel: 30 RPM · 165 mm/min
- 304 / 316 stainless: 20 RPM · 110 mm/min
M56x5.5 tap speeds and feeds: all materials, form taps and G84 code
Common questions
- What size drill for a M56x5.5 tap?
- Use a 50.50 mm drill (50.50 mm) for a M56x5.5 cutting tap at 75% thread.
- What drill for a M56x5.5 roll (form) tap?
- About 53.57 mm; the nearest standard drill is 53.5 mm. Check your tap maker's table.
Other Metric 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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