3.4 mm Drill Size

metric drill

3.4 mm 0.1339 in 3.40 mm

A 3.4 mm drill measures 0.1339 in. It taps 3 threads in this chart.

What a 3.4 mm 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 3.4 mm drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
#8-36	83.4%	#29	77.6%
#8-32	74.1%	#29	69.0%
M4 x 0.7	66.0%	3.3 mm	77.0%

Drills either side

3.3 mm 0.1299 in · 3.3 mm Next size down
#29 0.136 in · 3.45 mm Next size up

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

3.4 mm drill: common questions

What size is a 3.4 mm drill?

0.1339 inches, which is 3.40 mm. It is a metric drill.

What can I tap with a 3.4 mm drill?

3 threads: #8-36 at 83.4%, #8-32 at 74.1%, M4 x 0.7 at 66.0%.

What drill is next to a 3.4 mm?

Down: 3.3 mm at 0.1299 in. Up: #29 at 0.136 in.