1-1/2-12 UNF tap drill size

1-27/64 drill — 1.4219 in / 36.12 mm (72% thread)

Major Ø 1.5000 in · 12 threads per inch · fine series. The chart pick targets 75% thread; nearby standard drills:

Drill	Decimal (in)	mm	Thread %
1-7/16	1.4375	36.51	58%
1-27/64	1.4219	36.12	72%
1-13/32	1.4063	35.72	87%
1-25/64	1.3906	35.32	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: 1-1/2-6 UNC