21/32 in Drill Size

fractional drill

21/32″ 0.6562 in 16.67 mm

A 21/32 in drill is the standard tap drill for 3/4-10.

What a 21/32 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 21/32 in drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
3/4-10 chart drill	72.2%	21/32″	72.2%
M18 x 1.5	68.3%	16.5 mm	77.0%
M18 x 2	51.2%	16 mm	77.0%

Other jobs for a 21/32 in

Clearance hole: The through hole a bolt passes in, not a tapped hole: close fit for 5/8-11, close fit for 5/8-18, close fit for 5/8-24. See the clearance hole chart.

Drills either side

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21/32 in drill: common questions

What size is a 21/32 in drill?

0.6562 inches, which is 16.67 mm. It is a fractional drill.

What can I tap with a 21/32 in drill?

3 threads: 3/4-10 at 72.2%, M18 x 1.5 at 68.3%, M18 x 2 at 51.2%.

Is a 21/32 in drill the standard tap drill for anything?

Yes, for 3/4-10 (72.2% thread). That is the size published tap and drill charts give.

Is a 21/32 in drill used for clearance holes?

Yes: close fit for 5/8-11, close fit for 5/8-18, close fit for 5/8-24. A clearance hole is not tapped; the bolt passes through it.

What drill is next to a 21/32 in?

Down: 16.6 mm at 0.6535 in. Up: 16.7 mm at 0.6575 in.