M10 × 1.5 tap drill size
8.50 mm drill — or Q (0.3320 in) = 80% thread
M10 coarse series, 1.5 mm pitch. Tap drill Ø = nominal − pitch = 10 − 1.5 = 8.50 mm (≈77% thread, the standard chart value).
| Drill | Size | Thread % |
|---|---|---|
| 8.50 mm | 0.3346 in | 77% |
| Q (inch) | 0.3320 in / 8.43 mm | 80% |
Rounding to your nearest stock drill moves the thread percentage only a few points. Cut taps only — roll-form taps need a larger hole. Verify before you cut.
Need a different thread percentage? Open the tap drill calculator · Metric tap chart · All calculators