#55 Drill Size

number drill

#55 0.052 in 1.32 mm

A #55 drill measures 0.052 in. It taps 1 thread in this chart.

What a #55 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 #55 drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
M1.6 x 0.35	61.4%	1.25 mm	77.0%

Other jobs for a #55

Hard-material tap drill: The size to use in stainless or tool steel for #0-80, where it leaves a shallower thread than the standard drill and cuts tapping torque.

Drills either side

1.3 mm 0.0512 in · 1.3 mm Next size down
1.5 mm 0.0591 in · 1.5 mm Next size up

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

#55 drill: common questions

What size is a #55 drill?

0.052 inches, which is 1.32 mm. It is a number drill.

What can I tap with a #55 drill?

1 thread: M1.6 x 0.35 at 61.4%.

What drill is next to a #55?

Down: 1.3 mm at 0.0512 in. Up: 1.5 mm at 0.0591 in.