A Drill Size

letter drill

A 0.234 in 5.94 mm

A A drill measures 0.234 in. It taps 1 thread in this chart.

What a A 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 A 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	81.3%	6 mm	77.0%

Drills either side

#1 0.228 in · 5.79 mm Next size down
B 0.238 in · 6.05 mm Next size up

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

A drill: common questions

What size is a A drill?

0.234 inches, which is 5.94 mm. It is a letter drill.

What can I tap with a A drill?

1 thread: M7 x 1 at 81.3%.

What drill is next to a A?

Down: #1 at 0.228 in. Up: B at 0.238 in.