M5×0.8 tap drill size
Use a 4.2mm drill (4.20 mm) for a M5×0.8 cutting tap at 75% thread.
| Tap type | Drill | Decimal (mm) |
|---|---|---|
| Cutting tap, 75% thread | 4.2mm | 4.20 |
| Cutting tap, 50% thread (hard material) | 4.5mm | 4.50 |
| Roll / form tap, 65% thread | 4.65 mm | 4.65 |
| Helicoil / STI insert (M5×0.8×1D) | 5.6mm | 5.60 |
- Pitch
- 0.8 mm
- Major Ø
- 5.00
- Pitch Ø
- 4.48
- Minor Ø
- 4.13
M5×0.8 tapping speeds and feeds
Feed = pitch (0.8 mm per rev). Starting points for a general-purpose HSS cut tap:
- Aluminum 6061 / 7075: 1,360 RPM · 1088 mm/min
- Free-machining / mild steel: 390 RPM · 312 mm/min
- 304 / 316 stainless: 190 RPM · 152 mm/min
M5×0.8 tap speeds and feeds: all materials, form taps and G84 code · 4.2mm drill size and speeds
Common questions
- What size drill for a M5×0.8 tap?
- Use a 4.2mm drill (4.20 mm) for a M5×0.8 cutting tap at 75% thread.
- What drill for a M5×0.8 roll (form) tap?
- About 4.65 mm; the nearest standard drill is 4.65 mm. Check your tap maker's table.
- What drill for a M5×0.8 Helicoil?
- Drill 5.6mm (5.60 mm), then tap with the M5×0.8 STI tap.
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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