1-7/32 in Drill Size

fractional drill

1-7/32″ 1.2188 in 30.96 mm

A 1-7/32 in drill is the standard tap drill for 1-3/8-6.

What a 1-7/32 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 1-7/32 in drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
M33 x 2	78.7%	31 mm	77.0%
1-3/8-6 chart drill	72.1%	1-7/32″	72.1%

Other jobs for a 1-7/32 in

Form-tap hole: The published roll-tap hole for 1-1/4-12. A form tap displaces metal instead of cutting it, so it needs this larger hole.
Clearance hole: The through hole a bolt passes in, not a tapped hole: normal fit for 1-1/8-7, normal fit for 1-1/8-12. See the clearance hole chart.

Drills either side

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1-7/32 in drill: common questions

What size is a 1-7/32 in drill?

1.2188 inches, which is 30.96 mm. It is a fractional drill.

What can I tap with a 1-7/32 in drill?

2 threads: M33 x 2 at 78.7%, 1-3/8-6 at 72.1%.

Is a 1-7/32 in drill the standard tap drill for anything?

Yes, for 1-3/8-6 (72.1% thread). That is the size published tap and drill charts give.

Is a 1-7/32 in drill used for clearance holes?

Yes: normal fit for 1-1/8-7, normal fit for 1-1/8-12. A clearance hole is not tapped; the bolt passes through it.

What drill is next to a 1-7/32 in?

Down: 1-13/64 in at 1.2031 in. Up: 31 mm at 1.2205 in.