#39 Drill Size

number drill

#39 0.0995 in 2.53 mm

A #39 drill measures 0.0995 in. It taps 2 threads in this chart.

What a #39 drill taps

Every thread this drill cuts between 50% and 85% of thread, deepest first. Outside that band it is the wrong drill for the job, so nothing below that line is listed.

Threads a #39 drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
#5-40	78.5%	#38	72.4%
M3 x 0.5	72.8%	2.5 mm	77.0%

Drills either side

2.5 mm 0.0984 in · 2.5 mm Next size down
2.55 mm 0.1004 in · 2.55 mm Next size up

All drill sizes → · Open this drill in the calculator →

#39 drill: common questions

What size is a #39 drill?

0.0995 inches, which is 2.53 mm. It is a number drill.

What can I tap with a #39 drill?

2 threads: #5-40 at 78.5%, M3 x 0.5 at 72.8%.

What drill is next to a #39?

Down: 2.5 mm at 0.0984 in. Up: 2.55 mm at 0.1004 in.