#50 Drill Size

number drill

#50 0.070 in 1.78 mm

A #50 drill is the standard tap drill for #2-56 and #2-64.

What a #50 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 #50 drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
#2-64 chart drill	78.8%	#50	78.8%
#2-56 chart drill	69.0%	#50	69.0%

Drills either side

1.75 mm 0.0689 in · 1.75 mm Next size down
1.8 mm 0.0709 in · 1.8 mm Next size up

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

#50 drill: common questions

What size is a #50 drill?

0.070 inches, which is 1.78 mm. It is a number drill.

What can I tap with a #50 drill?

2 threads: #2-64 at 78.8%, #2-56 at 69.0%.

Is a #50 drill the standard tap drill for anything?

Yes, for #2-56 (69.0% thread) and #2-64 (78.8% thread). That is the size published tap and drill charts give.

What drill is next to a #50?

Down: 1.75 mm at 0.0689 in. Up: 1.8 mm at 0.0709 in.