Hood,
I'm not sure. I'm sure my servos could be tuned a little better, but truth be told I've tuned them so many times I'm almost to the point where I'm over it. Back when the machine was missing steps due to the optocouplers they were more difficult to tune, so the new encoders have helped quite a bit. But I think the feedback from the servos to the drives are whats getting me know. I've adjusted the three potentiometers on the front of the servo drive to no avail.
The thing is, I had it running fairly well before I tried to reconfigure Mach for ridgid tapping. In the process of switching the spindle to the control of the ipa rather than the plc, I accidentally deleted my M6 macro and tried to recover it by reinstalling mach3. Ever since the reinstall, the machine has been having trouble. Its like its not capable of look ahead anymore. If I'm running a program at 45ipm and each point is only a few thou away from the next, say in the case of a helical plunge, the machine never has the chance to accelerate to the next point. So while the machine is commanding the drives to move at 45ipm its actually moving at 1 to 3 ipm. CS labs suspects that my mach3 file is corrupt. Don't know how that would happen, but I'll try downloading and reinstalling a fresh copy. I would make the jump to mach4 but rigid tapping isn't supported there and I've grown fond of rigid tapping.