C Drill Size

letter drill

C 0.242 in 6.15 mm

A C drill measures 0.242 in. It taps 1 thread in this chart.

What a C 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 C drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
M7 x 1	65.7%	6 mm	77.0%

Drills either side

B 0.238 in · 6.05 mm Next size down
D 0.246 in · 6.25 mm Next size up

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

C drill: common questions

What size is a C drill?

0.242 inches, which is 6.15 mm. It is a letter drill.

What can I tap with a C drill?

1 thread: M7 x 1 at 65.7%.

What drill is next to a C?

Down: B at 0.238 in. Up: D at 0.246 in.