#19 Drill Size

number drill

#19 0.166 in 4.22 mm

A #19 drill measures 0.166 in. It taps 2 threads in this chart.

What a #19 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 #19 drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
M5 x 0.8	75.4%	4.2 mm	77.0%
#10-32	59.1%	#21	76.4%

Other jobs for a #19

Hard-material tap drill: The size to use in stainless or tool steel for #10-32, where it leaves a shallower thread than the standard drill and cuts tapping torque.

Drills either side

4.2 mm 0.1654 in · 4.2 mm Next size down
4.3 mm 0.1693 in · 4.3 mm Next size up

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

#19 drill: common questions

What size is a #19 drill?

0.166 inches, which is 4.22 mm. It is a number drill.

What can I tap with a #19 drill?

2 threads: M5 x 0.8 at 75.4%, #10-32 at 59.1%.

What drill is next to a #19?

Down: 4.2 mm at 0.1654 in. Up: 4.3 mm at 0.1693 in.