#3-56 UNF tap drill size

#45 drill — 0.0820 in / 2.08 mm (73% thread)

Major Ø 0.0990 in · 56 threads per inch · fine series. The chart pick targets 75% thread; nearby standard drills:

Drill	Decimal (in)	mm	Thread %
#45	0.0820	2.08	73%
#46	0.0810	2.06	78%
#47	0.0785	1.99	88%
5/64	0.0781	1.98	90%

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: #3-48 UNC