[markotime]

Z is spindle, 1 rev per mm
X is normal logitudinal axis,
G01 X-20 Z20
Which gives 20mm of 1mm pitch thread.
Under testing, with preset Y (cross slide) - for first run testing on my machine.
After what may be a TIME interval, carriage motion pauses, then continues.
At faster rates, it goes farther, but still interrupts. Any ideas? thanks.

[markotime]

If "time" is really the variable causing the pause, it must be the thermal shutdown feature of the DRV8825s. I'll drop the current a bit and install a fan, and report back.

[hfjbuis]

If it is the driver over heating (or powersupply) you are also losing steps!

Has reducing the current solved your problem?

[markotime]

Decided to go back to single stepping on x and y, which will also reduce current duty cycle (some 1/32 microsteps draw 1.4* single step current). Also switched to UGS from GRBLGRU, to get more macro options, and I like it better, but have had some issues with calibration,
an intermittent connection, some smoke escaping from my nano, and a persistent mystery. But yes, I feel certain that the current reduction will help. I also had a heatsink that was not making a good thermal bond on the axis in question.
(Having to switch between command line and back with each parameter change in GRBLGRU was driving me crazy, and while I like many of its features, not quite ready for it. Thanks!)