Ok, thanks for the heads up! I'll have to give that thread a good read.
Several years ago when I built this machine I worked out what my worst case torque requirements should be, and I had some margin iirc. I'm attempting to re-do those calculations now. Bottom line is, I see a jog that mach3 is commanding when backlash compensation is enabled that I cant explain, and it is on the very axis that is inexplicably stalling for me. Generically, the answer for a stalling motor is more torque. If you have enough torque to extrude away the dovetails on your mill table, you will never have a motor stall
So I expect that most people would just chalk it up to physics and walk away, either choosing to up motor torque or decrease their feed/acceleration rates.
I have enough torque that I dont necessarily have to have the endmill spinning to pull it through a peice of wood... - I have always been spindle limited on machining. I have done everything I can to generate the peak g-loads I could ever see on my table and I have always been unable to induce this oddball failure mode except for when I'm using backlash compensation and on very high aspect ratio moves. Throw in the odd lurch behavior and I become suspicious that either mach3 by default is doing something unexpected BY DESIGN, or one of my files has become corrupted, or there is some kind of either mechanical or electrical cross-talk between systems that is making this a nonlinear problem :\
I can upgrade motors and probably handle whatever accelerations mach3 feeds my gear, but it would be nice to understand if mach3 is systematically making people de-tune their machines to alleviate these little phantom failures that crop up that may or may not be associated with this peculiar jumping movement I've discovered.
I can work around this issue, I was just hoping someone reading the forum was so intimately familiar with the inner workings of mach3 that they would be able to give a little insight into how mach3 plans/executes moves like backlash compensation. At any rate this has been a learning experience for me, and hopefully for others.