#45 Drill Size

number drill

#45 0.082 in 2.08 mm

A #45 drill is the standard tap drill for #3-56.

What a #45 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 #45 drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
#3-56 chart drill	73.3%	#45	73.3%
M2.5 x 0.45	71.3%	2.05 mm	77.0%
#3-48	62.8%	#47	75.7%

Other jobs for a #45

Hard-material tap drill: The size to use in stainless or tool steel for #3-48, where it leaves a shallower thread than the standard drill and cuts tapping torque.

Drills either side

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

#45 drill: common questions

What size is a #45 drill?

0.082 inches, which is 2.08 mm. It is a number drill.

What can I tap with a #45 drill?

3 threads: #3-56 at 73.3%, M2.5 x 0.45 at 71.3%, #3-48 at 62.8%.

Is a #45 drill the standard tap drill for anything?

Yes, for #3-56 (73.3% thread). That is the size published tap and drill charts give.

What drill is next to a #45?

Down: #46 at 0.081 in. Up: 2.1 mm at 0.0827 in.