M33 × 2 tap drill size

31.00 mm drill — or 1-7/32 (1.2188 in) = 79% thread

M33 fine series, 2 mm pitch. Tap drill Ø = nominal − pitch = 33 − 2 = 31.00 mm (≈77% thread, the standard chart value).

DrillSizeThread %
31.00 mm1.2205 in77%
1-7/32 (inch)1.2188 in / 30.96 mm79%

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.