7/16-20 UNF tap drill size

25/64 drill — 0.3906 in / 9.92 mm (72% thread)

Major Ø 0.4375 in · 20 threads per inch · fine series. The chart pick targets 75% thread; nearby standard drills:

Drill	Decimal (in)	mm	Thread %
X	0.3970	10.08	62%
25/64	0.3906	9.92	72%
W	0.3860	9.80	79%
V	0.3770	9.58	93%

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: 7/16-14 UNC