What size drill bit should I use with a 12mm tap?

Question

What size drill bit should I use with a 12mm tap?

Answer 1

do you mean to tap as in a plate of metal? if so i would start smaller and test the tap you can step up a size but once you drill to big your knacked. start with 10mm and try the tap.

Answer 2

this is a link to recommended tap drill size tables for inch and metric tap drill sizes, that give the answer.

the drill size does not depend only on the tap size but also on the  type of thread.

http://www.newmantools.com/tapdrill.htm#...

Answer 3

Is this tap coarse, or fine thread? In the USA, a 27/64" drill is recommended. I would work up to this size, though. Start with a small hole and then drill it out with increasingly larger drills until you get to 27/64".

For 12mm x 1.75 thread a 27/64" drill is recommended, 10.25mm drill if you have metric drills.

For 12mm x 1.50 thread a 10.5mm drill is recommended.

For 12mm x 1.25 thread a 10.75mm drill is recommended.

Answer 4

The tap should tell you, look on it for #'s.