rigid tapping issues

[stebanski]

Hi guys,
I have a haas vf2 1995 model that suposedly has rigid tapping installed.
the rigid tapping is on in the parameters but I have never been able to get a good thread. I've tried things such as low gear overide to keep the spindle motor at a lower rpm for a more instantaneous stop and start, but no difference, the threads are just loose. 1/4-20 threads by the way. I've tried varying the feed rate up or down a little to compensate but no luck, still loose.

But then, just by chance, I happened to notice that the rpm shown on the diagnostics page is slightly different from the programed feedrate which is the same as that shown on the current commands page. So I've tried to vary the rpm in the program so that the rpm in the diagnostics page shows the proper rpm for the tap. When I tried this with the low gear overide function on, I stalled the spindle from lack of torque I guess, (this was with a 3/8 -16 tap in aluminum by the way) and when I tried this with the low gear overide function off I got the same loose threads.

I'm guessing I have tach issues but dont want to call "Haas man" and spend a couple of grand on the problem.

By the way, the spindle temp on the same diagnostics page is way out of whack also, showing 270 degrees F. when the machine is cold, for what ever thats worth.

If anyone has an idea please help.

[ltmquik]

How are you holding the tap? You should try using a tap holder made for ridgid tapping. Some claim that one can hold taps in just a collet. I have found that some taps run out just enough to produce threads that will fail the thread gages.

[stebanski]

I'm holding it in a collet and have less than .001" runout. I'm pretty shure the machine isn't acting right.

[mikenaturalice]

have you tried the reverse speed? you can set this in parameters to 1x, 2x etc. i have found 2x works pretty good

[HAILINHAAS]

loose encoder belt .. but you would have problems with the tool changer if that was the case. what does the G84 block look like? post it.