M3.5 × 0.6 tap drill size

2.90 mm drill — or #33 (0.1130 in) = 81% thread

M3.5 coarse series, 0.6 mm pitch. Tap drill Ø = nominal − pitch = 3.5 − 0.6 = 2.90 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