12.8 mm Drill Size

metric drill

12.8 mm 0.5039 in 12.80 mm

A 12.8 mm drill is the standard tap drill for M14 x 1.25.

What a 12.8 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 12.8 mm drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
9/16-18	81.2%	33/64″	65.0%
M14 x 1.25 chart drill	73.9%	12.8 mm	73.9%
M14 x 1.5	61.6%	12.5 mm	77.0%
9/16-12	54.1%	31/64″	72.1%

Other jobs for a 12.8 mm

Hard-material tap drill: The size to use in stainless or tool steel for M14 x 1.5, 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 →

12.8 mm drill: common questions

What size is a 12.8 mm drill?

0.5039 inches, which is 12.80 mm. It is a metric drill.

What can I tap with a 12.8 mm drill?

4 threads: 9/16-18 at 81.2%, M14 x 1.25 at 73.9%, M14 x 1.5 at 61.6%, 9/16-12 at 54.1%.

Is a 12.8 mm drill the standard tap drill for anything?

Yes, for M14 x 1.25 (73.9% thread). That is the size published tap and drill charts give.

What drill is next to a 12.8 mm?

Down: 12.7 mm at 0.500 in. Up: 12.9 mm at 0.5079 in.