In article , Harold and Susan Vordos says...

I, for one, do. Spiral point taps are intended to be power driven and are
not easy to start by hand. They're prone to damaging the starting threads
because they don't self align well, the way a taper tap does. . There's
no better tap on the market as far as I'm concerned, but I also have a
Procunier tapping head.

Spiral point taps and two- or three- flute gun taps are not the same
thing however. Spiral point taps are designed to extract the chips
backwards out the hole in a continous cut. The gun taps are ground
to sling the chips forwards in the hole, and as such are best used
in through holes.

I would not shy away from power tapping a hole like the OP mentioned
using a two flute gun tap. I've done stuff like that with nothing
more than a reversible, variable speed milwaukee hand drill.

With a procunier head, it's dead easy.

I prefer two flute gun taps over regular hand taps any day, even
when tapping stuff by hand. The need to stop and clean out small
holes as the chips accumulate (if they cannot be through holes) is
not a terribly big deal as most of the stuff I do is not production,
it's one off.

I think most of the gun taps are simply higher quality than the
hand taps I see.

Jim


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