M8 Tap Drill Size and Drill Bit for M8 Thread
Use a 6.8mm drill bit
M8×1.25 · 0.2677 in / 6.8 mm · ~75% thread
M8 is a widely used metric thread. The tap drill is major minus pitch: 8.0 minus 1.25 equals 6.8 mm.
At a glance
| Tap drill | 6.8mm |
|---|---|
| Inches | 0.2677 in |
| Millimetres | 6.8 mm |
| Major diameter | 8 mm |
| Pitch | 1.25 mm |
| Fine pitch | M8×1 → drill 7.00 mm |
Why this size
drillØ = major − pitch = 8 − 1.25 = 6.75 mm → tap drill 6.8mm
M8 x 1.0 fine pitch uses a 7.0 mm drill. The standard M8 x 1.25 tap drill is 6.8 mm.
Related sizes
Compare with adjacent threads – coarse, fine and the opposite measurement system: