On May 3, 7:17*pm, John Doe wrote:


Note that it also indicates that a #Q drill is 8.4328 mm
diameter, so an 8mm hole is -probably- too small to attempt with
a cheap tap.

Can anyone specify a 3/8-24 tap that might work without enlarging
the hole?

No.
But enlarging the hole is not that big a deal. You are not enlarging
the hole by a lot. So even done free hand, the hole will be very
close to centered. And if you get the hole a bit bigger, it should
not be a problem. The ratio of the threaded length to the diameter
is large, so you will have plenty of strength. I would probably use
a H3 tap. A H1 would give you slightly more strength , but with the
ratio of the length to diameter much greater than one, you do not need
the strength.

Dan