Tap Drill Size Chart

16.5 mm Drill Size

metric drill

16.5 mm 0.6496 in 16.50 mm

A 16.5 mm drill is the standard tap drill for M18 x 1.5.

What a 16.5 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 16.5 mm drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread % thread Chart drill Chart %
3/4-10 77.3% 21/32″ 72.2%
M18 x 1.5 chart drill 77.0% 16.5 mm 77.0%
M18 x 2 57.7% 16 mm 77.0%

Drills either side

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16.5 mm drill: common questions

What size is a 16.5 mm drill?
0.6496 inches, which is 16.50 mm. It is a metric drill.
What can I tap with a 16.5 mm drill?
3 threads: 3/4-10 at 77.3%, M18 x 1.5 at 77.0%, M18 x 2 at 57.7%.
Is a 16.5 mm drill the standard tap drill for anything?
Yes, for M18 x 1.5 (77.0% thread). That is the size published tap and drill charts give.
What drill is next to a 16.5 mm?
Down: 16.4 mm at 0.6457 in. Up: 16.6 mm at 0.6535 in.