1-5/16 in Drill Size

fractional drill

1-5/16″ 1.3125 in 33.34 mm

A 1-5/16 in drill measures 1.3125 in. It taps 3 threads in this chart.

What a 1-5/16 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 1-5/16 in drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
M36 x 3	68.3%	33 mm	77.0%
1-3/8-12	57.7%	1-19/64″	72.1%
M36 x 4	51.3%	32 mm	77.0%

Other jobs for a 1-5/16 in

Hard-material tap drill: The size to use in stainless or tool steel for 1-3/8-12, where it leaves a shallower thread than the standard drill and cuts tapping torque.
Clearance hole: The through hole a bolt passes in, not a tapped hole: loose fit for 1-1/8-7, loose fit for 1-1/8-12. See the clearance hole chart.

Drills either side

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

1-5/16 in drill: common questions

What size is a 1-5/16 in drill?

1.3125 inches, which is 33.34 mm. It is a fractional drill.

What can I tap with a 1-5/16 in drill?

3 threads: M36 x 3 at 68.3%, 1-3/8-12 at 57.7%, M36 x 4 at 51.3%.

Is a 1-5/16 in drill used for clearance holes?

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

What drill is next to a 1-5/16 in?

Down: 33 mm at 1.2992 in. Up: 33.5 mm at 1.3189 in.