Hi RICH,
In a nutshell, I set everything up by the book at first, using releases prior to 008. I'm using a VFD with Steve Stallings PMDX 106.
For general threading, it work fairly well, probably acceptable for most applications but it wouldn't tolerate spindle speed variations during the passes.
After 008, everything got much, Much, MUCH better. I'm afraid to upgrade further.
I have never cut a long thread, like 1/2-20 x6" or such so to this day I'm not sure if it will produce a good thread but suspect that it will.
The slower ...the better but I sacrifice a little here to keep the cycle time as low as possible.
I looked everywhere for a full form insert for 48 tpi but I never found one. To eliminate the little feather edge at the peak of the thread, I first turn the OD of the threaded area just enough to allow a 1/8 Pitch flat on the thread tops.
I also had an air motor with a wire wheel mounted to the tool slide and controlled in the GCode file. It "de-Fuzzsed" the threads which worked well with the 272 alloy but when they went with the Ni Silver, the brush was not necessary.
All in all, I think most problems are with the setup....not Mach. With a good clean index signal, mine has always worked. And If I had a 20 HP spindle with a 200lb chuck it probably would have been fine all along.
Thanks All,
RC