25/64 in Drill Size

fractional drill

25/64″ 0.3906 in 9.92 mm

A 25/64 in drill is the standard tap drill for 7/16-20.

What a 25/64 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 25/64 in drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
7/16-20 chart drill	72.2%	25/64″	72.2%
7/16-14	50.5%	U	74.9%

Other jobs for a 25/64 in

Clearance hole: The through hole a bolt passes in, not a tapped hole: close fit for 3/8-16, close fit for 3/8-24, close fit for 3/8-32. See the clearance hole chart.

Drills either side

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25/64 in drill: common questions

What size is a 25/64 in drill?

0.3906 inches, which is 9.92 mm. It is a fractional drill.

What can I tap with a 25/64 in drill?

2 threads: 7/16-20 at 72.2%, 7/16-14 at 50.5%.

Is a 25/64 in drill the standard tap drill for anything?

Yes, for 7/16-20 (72.2% thread). That is the size published tap and drill charts give.

Is a 25/64 in drill used for clearance holes?

Yes: close fit for 3/8-16, close fit for 3/8-24, close fit for 3/8-32. A clearance hole is not tapped; the bolt passes through it.

What drill is next to a 25/64 in?

Down: 9.9 mm at 0.3898 in. Up: X at 0.397 in.