Tapping 17-4 w/acme tap

Trying to tap 17-4 stainless (H1100 condition) using a 3/4-6 Left hand acme tandem tap.
Machine is a TL-25. Hole size is correct. RPM is ~250, feed is .16667" per rev.
We are getting a 105 alarm (Z axis servo to large). Checked incoming voltage and the parameters match factory settings.
Local Haas dealer said there is not a lot they can do for us. Any suggestions?
I find it hard to believe we can not run this tap with this machine.

Thanks,
Joker

This one has been sitting here all day with no replies, for shame.

First thing I'll ask, by your error, does that mean you are getting a Z axis thrust alarm? If thats the case, your lead in/chamfer may not be adequete, or your tap is questionable/having a hard time starting for some reason.

Second thing, I don't care how many horses you have, those bastards take a lot. I've done a few by hand with the tandems, and they were not fun. Did 5/8-10 by hand through 2" of 4140, I was sore for quite a while.

Maybe give it a shot in some aluminum, watch the load meters and see what happens.

Actually you didn't say, how far are you getting into it before you alarm out? How deep are you going? Is the material so thin walled that you are squeezing the tap? Just throwing some stuff out there.

Acme thread

The tap is brand new and a brand name. It only goes in a couple of turns and when we release it out of the holder we can turn the tap by hand.
A test part was done in aluminum first, as this is customer supplied material, and everything worked well. Load meter was about 20%.
The part is large enough that there should not be any deflection.
The alarm said "Z axis servo to large". Could it be that the rpm is too fast for the feed?

Thanks,

I suspect that you are right, the z axis cant keep up with the feed at that rpm. Although that doesnt seem possible based on what you are doing, but I suspect that is the problem. Just for fun take the tap out of the holder and run the machine with less of a feed and see what happens. You may find that you are just on the edge of the limit.

Best suggestion I can offer.

Charles

Acme thread

I would almost accept that, but we ran the part in 6061 aluminum and it performed just fine.
Going to try slowing the rpm's.

Thanks,

At 250 rpm your feed in z is only 41.7 ipm. I doubt you have any problem with the z feed rate being too high. With a 1/4-20 tap at 1000 rpm the feed would be 50 ipm.

joker said:

I would almost accept that, but we ran the part in 6061 aluminum and it performed just fine.
Going to try slowing the rpm's.

Thanks,

Click to expand...

Then that should make it an easy decision, run the program with out the tool. If you get no alarm then it has to be because of the material you are trying to cut.

Charles

Problem solved

We solved the problem by putting the part in our VF-4 and running the tap. Spindle load went up to 130% but we got thru the parts without anything breaking.
Thanks for everyones input.

Joker

What about peck tapping?