wrote in message
...
I routinely have to tap 6-32 holes in the sides of 6061 aluminum 1/4
round by the hundreds. I thought I had it wired for a while, because I
was able to go through about 500 pieces before breaking a tap. Not the
end of the world. But today I broke 4 to go through the same amount.
I'm doing it the same way I did in the past, but something is going
wrong.

At any rate, I feel it's the lateral movement that is hurting me. On
the ones where I'm able to get the tap to go in perfectly straight,
you can feel that there's less resistance. The problem is that because
it's a round, it is very hard to get the piece clamped so the hole is
perfectly straight. I've been using a power drill, mainly because it
allows me to kind of adjust the angle a little if I feel too much
resistance. I would prefer to use a drill press with tap head, but I
don't know how you would align the hole with the tap properly, since
the part is round.

I'm not sure how they would do this in automated tooling. I guess
maybe do both the hole and tap at the same time somehow. I can't put
each piece in a clamp and move it each time, because that would take
forever. So I'm kind of at a loss right now. Breaking $40 of taps a
day isn't an option. Not to mention the time spent remaking the parts,
as the tap almost always breaks off without anything left sticking out
to extract it.
How about a drilling/tapping block with a hole for the rod and a cross hole
for the drill and tap? If you are doing it by hand making the cross hole
large enough for the tap would likely align the drill close enough. Or you
could use two holes and slide the rod accordingly.

Don Young