1-1/4-12 UNF tap drill size

1-11/64 drill — 1.1719 in / 29.77 mm (72% thread)

Major Ø 1.2500 in · 12 threads per inch · fine series. The chart pick targets 75% thread; nearby standard drills:

Drill	Decimal (in)	mm	Thread %
1-3/16	1.1875	30.16	58%
1-11/64	1.1719	29.77	72%
1-5/32	1.1563	29.37	87%
1-9/64	1.1406	28.97	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: 1-1/4-7 UNC