18.1 mm Drill Size

metric drill

18.1 mm 0.7126 in 18.10 mm

A 18.1 mm drill measures 0.7126 in. It taps 3 threads in this chart.

What a 18.1 mm 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 18.1 mm drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
M20 x 2	73.1%	18 mm	77.0%
M20 x 2.5	58.5%	17.5 mm	77.0%
3/4-20	57.6%	45/64″	72.2%

Other jobs for a 18.1 mm

Hard-material tap drill: The size to use in stainless or tool steel for M20 x 2.5, where it leaves a shallower thread than the standard drill and cuts tapping torque.

Drills either side

18 mm 0.7087 in · 18 mm Next size down
18.2 mm 0.7165 in · 18.2 mm Next size up

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

18.1 mm drill: common questions

What size is a 18.1 mm drill?

0.7126 inches, which is 18.10 mm. It is a metric drill.

What can I tap with a 18.1 mm drill?

3 threads: M20 x 2 at 73.1%, M20 x 2.5 at 58.5%, 3/4-20 at 57.6%.

What drill is next to a 18.1 mm?

Down: 18 mm at 0.7087 in. Up: 18.2 mm at 0.7165 in.