30.5 mm Drill Size

metric drill

30.5 mm 1.2008 in 30.50 mm

A 30.5 mm drill measures 1.2008 in. It taps 2 threads in this chart.

What a 30.5 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 30.5 mm drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
1-3/8-6	80.5%	1-7/32″	72.1%
M33 x 3.5	55.0%	29.5 mm	77.0%

Other jobs for a 30.5 mm

Hard-material tap drill: The size to use in stainless or tool steel for M33 x 3.5, where it leaves a shallower thread than the standard drill and cuts tapping torque.

Drills either side

1-3/16″ 1.1875 in · 30.16 mm Next size down
1-13/64″ 1.2031 in · 30.56 mm Next size up

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

30.5 mm drill: common questions

What size is a 30.5 mm drill?

1.2008 inches, which is 30.50 mm. It is a metric drill.

What can I tap with a 30.5 mm drill?

2 threads: 1-3/8-6 at 80.5%, M33 x 3.5 at 55.0%.

What drill is next to a 30.5 mm?

Down: 1-3/16 in at 1.1875 in. Up: 1-13/64 in at 1.2031 in.