On 2017-03-19, Bob Engelhardt wrote:
I was rummaging through my tap collection and came across a couple of
forming taps. I have no idea how they got there, but there they were.
Now, the question is: where are they better used than cutting taps?

Blind holes is one example, as they don't form chips which need
to be cleared out. Just make sure that the tapping head stops before
they bottom out. :-)

Your workpiece should be a fairly ductile metal, of course.
Forget about tapping hardened tool steel -- but then cutting taps don't
do to well there, either. :-)

I've even used them in Teflon, where the material expands to
grip the screw once it is in place.

Since they are more particular about the hole size, I won't use them
unless they have some advantage.

Be sure that you use the right hole size. You can look it up in
a table in _Machinery's Handbook_, or in certain machinist's
calculators.

Enjoy,
DoN.

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