51/64 in Drill Size

fractional drill

51/64″ 0.7969 in 20.24 mm

A 51/64 in drill measures 0.7969 in. It taps 4 threads in this chart.

What a 51/64 in 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 51/64 in drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
7/8-14	84.2%	13/16″	67.4%
M22 x 2	67.7%	20 mm	77.0%
M22 x 2.5	54.2%	19.5 mm	77.0%
7/8-9	54.1%	49/64″	75.8%

Drills either side

20 mm 0.7874 in · 20 mm Next size down
20.5 mm 0.8071 in · 20.5 mm Next size up

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

51/64 in drill: common questions

What size is a 51/64 in drill?

0.7969 inches, which is 20.24 mm. It is a fractional drill.

What can I tap with a 51/64 in drill?

4 threads: 7/8-14 at 84.2%, M22 x 2 at 67.7%, M22 x 2.5 at 54.2%, 7/8-9 at 54.1%.

What drill is next to a 51/64 in?

Down: 20 mm at 0.7874 in. Up: 20.5 mm at 0.8071 in.