1-12 UNF tap drill size

59/64 drill — 0.9219 in / 23.42 mm (72% thread)

Major Ø 1.0000 in · 12 threads per inch · fine series. The chart pick targets 75% thread; nearby standard drills:

Drill	Decimal (in)	mm	Thread %
15/16	0.9375	23.81	58%
59/64	0.9219	23.42	72%
29/32	0.9063	23.02	87%
57/64	0.8906	22.62	101%

Cut taps only — roll-form taps need a larger hole. 65–75% suits general work; drop toward 55% in tough material. Verify before you cut.

Same size, coarse series: 1-8 UNC