3 Axis CNC router

[AndyUK]

I'm with Neale, sounds like Z is trying to move too fast.

I've had to detune my Z quite substantially compared to the X and Y speeds, the rapid upwards Z motions at the start of my cuts caused it to stall. Wonder if its something about moving a heavy spindle directly against gravity - although you'd hope that was only a small factor. It runs approximately 40% of the rapids speeds of X and Y (after correcting for screw pitch differences) and about half the acceleration. Its a 1605 running on a 3.1nm Nema 23, velocity 2m/min, 200mm/s^2 accel. Probably conservative, but works for me. Not a problem in every day life though as the travel is so much smaller :)

Regards the special cable, it requires a slightly custom job. I used a RJ11 crimper and some CAT5 to knock up one - you only use three wires. If you want I'll lend you one.