18.4 mm Drill Size

metric drill

18.4 mm 0.7244 in 18.40 mm

A 18.4 mm drill measures 0.7244 in. It taps 2 threads in this chart.

What a 18.4 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 18.4 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 1.5	82.1%	18.5 mm	77.0%
M20 x 2	61.6%	18 mm	77.0%

Other jobs for a 18.4 mm

Hard-material tap drill: The size to use in stainless or tool steel for M20 x 2, where it leaves a shallower thread than the standard drill and cuts tapping torque.

Drills either side

18.3 mm 0.7205 in · 18.3 mm Next size down
18.5 mm 0.7283 in · 18.5 mm Next size up

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

18.4 mm drill: common questions

What size is a 18.4 mm drill?

0.7244 inches, which is 18.40 mm. It is a metric drill.

What can I tap with a 18.4 mm drill?

2 threads: M20 x 1.5 at 82.1%, M20 x 2 at 61.6%.

What drill is next to a 18.4 mm?

Down: 18.3 mm at 0.7205 in. Up: 18.5 mm at 0.7283 in.