M12 × 1.25 tap drill size
10.75 mm drill — or 27/64 (0.4219 in) = 79% thread
M12 fine series, 1.25 mm pitch. Tap drill Ø = nominal − pitch = 12 − 1.25 = 10.75 mm (≈77% thread, the standard chart value).
| Drill | Size | Thread % |
|---|---|---|
| 10.75 mm | 0.4232 in | 77% |
| 27/64 (inch) | 0.4219 in / 10.72 mm | 79% |
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