I brought this up once before and got a lot of good advice. The
original problem was tapping 6-32 holes in side of 1/4" aluminum
round. Each piece has one hole. I use to do this by drilling the holes
on the press, then tapping with a power drill. Sounds primitive, but
it worked... On hundreds of them, no problem. Then it stopped working
and I never did figure out why. I can't get through 15 without
breaking a tap now and I've tried everything. The first time the
consensus seemed to be that it would be best to use a combo drill/tap
bit on a tapping head. I agree, except, I never got around to it. The
need for these parts hadn't happen since the last time... but I
decided I would do it that way when it comes up again. Well, it came
up again... Except this time the rounds already had the #36 holes
drilled in them... Hundreds of them. So I have no choice but to tap
them as is. Long story longer, I went through about $50 worth of taps
today just trying to get through 40 of them. And even just that took a
ridiculous effort.

So now what? I haven't tried it yet, but I'm thinking maybe opening
the holes to 7/64" would help? Or would that weaken the thread too
much? I don't know, I'm pretty much desperate for a solution at this
point. I've tried every type of tap, tap fluid, technique... I'm out
of ideas.