M24 × 2 tap drill size

22.00 mm drill — or 55/64 (0.8594 in) = 84% thread

M24 fine series, 2 mm pitch. Tap drill Ø = nominal − pitch = 24 − 2 = 22.00 mm (≈77% thread, the standard chart value).

DrillSizeThread %
22.00 mm0.8661 in77%
55/64 (inch)0.8594 in / 21.83 mm84%

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.