As a test, I removed the Arduino board, and controlled the stepper board directly from my lathe’s PC parallel port using Mach3 (with settings modified for the Nomad stepper board). The glitches persisted, leading me to conclude that the problem is an electrical problem with the stepper board itself. Possibly a few boards have a component or two that is out of tolerance, leading to increased noise susceptibility on the step input line. I’ve been in contact with Rob and Jorge about my testing.
