63/64 in Drill Size

fractional drill

63/64″ 0.9844 in 25.00 mm

A 63/64 in drill is the standard tap drill for 1-1/8-7.

What a 63/64 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 63/64 in drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
M27 x 2	76.9%	25 mm	77.0%
1-1/8-7 chart drill	75.8%	63/64″	75.8%
M27 x 3	51.2%	24 mm	77.0%

Other jobs for a 63/64 in

Form-tap hole: The published roll-tap hole for 1-20. A form tap displaces metal instead of cutting it, so it needs this larger hole.

Drills either side

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

63/64 in drill: common questions

What size is a 63/64 in drill?

0.9844 inches, which is 25.00 mm. It is a fractional drill.

What can I tap with a 63/64 in drill?

3 threads: M27 x 2 at 76.9%, 1-1/8-7 at 75.8%, M27 x 3 at 51.2%.

Is a 63/64 in drill the standard tap drill for anything?

Yes, for 1-1/8-7 (75.8% thread). That is the size published tap and drill charts give.

What drill is next to a 63/64 in?

Down: 25 mm at 0.9843 in. Up: 1 in at 1.000 in.