Terry1956,

Background: I've converted a Myford ML7 to CNC. For better or worse.

You have 3 questions which need to be dealt with largely separately.

Your "cutting out". There's a lot of possibilities, and very little info. From the outset I'd look at your NEMA 34s and question the 24V supply voltage - you really should be up at 60 volts or higher. In fact the first hit I had with a CL86T indicates a 30V minimum supply rail. Conversely, I'd question a NEMA 34, but as you've not indicated what lathe you have.... Anyway - you'll need to fault-find a bit more for us. Are the stepper drivers getting hot?, what's the supply voltage doing when the system freezes?, are there any fault indications on the stepper driver? Does the same happen if the steppers are mechanically uncoupled from the axis-drives? Does this happen on one axis, or both? Also, for background - are you using the original trapezoidal screws or have you replaced these? Photos are always welcomed (though you may have a 10 post limit to hit before you can post those?) Please, help us to help you - provide some more detail.

The "100khz breakout boards" most certainly will tie you to Mach3. If you want to consider another motion controller (such as LinuxCNC) then you'll need something different. If you have a parallel port then this is one way forward; the LinuxCNC route also favors/supports the Mesa hardware - good kit, but expensive, and perhaps unobtainium with the current semiconductor crisis. Others will advise on more hardware/software combinations - I've only used LinuxCNC/Mesa.

Linux vs Mach3. By this I expect you mean LinuxCNC - which is what I use (and, I think what most people here use for turning). It's not that it's the best, more than it's the least worst. It's powerful, certainly, and supports the turning functions well. But if I was to assume that you've not used Linux before then my first bit of advice would be to understand that you have a vertical learning curve ahead of you. Others on this forum with far more experience of LinuxCNC would be able to advise further and more accurately. I'd simply say that it's not straightforward. "Calibration" is a funny old word - what are you trying to calibrate? the X/Z axis are much of a muchness regardless of Mach3 Turn or LinuxCNC - both require you to understand the basic mechanics of the CNC conversion (offset / turns, and steps/turn). What both Mach3 and LinuxCNC do require for any basic threading is a form of spindle-encoder - and for this to be calibrated. Have you had a thought for this?