M27 × 2 tap drill size

25.00 mm drill — or 63/64 (0.9844 in) = 77% thread

M27 fine series, 2 mm pitch. Tap drill Ø = nominal − pitch = 27 − 2 = 25.00 mm (≈77% thread, the standard chart value).

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