#12-24 UNC tap drill size

#16 drill — 0.1770 in / 4.50 mm (72% thread)

Major Ø 0.2160 in · 24 threads per inch · coarse series. The chart pick targets 75% thread; nearby standard drills:

Drill	Decimal (in)	mm	Thread %
#15	0.1800	4.57	67%
#16	0.1770	4.50	72%
#17	0.1730	4.39	79%
11/64	0.1719	4.37	82%

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, fine series: #12-28 UNF