CNC-USB (PlanetCNC)

[Boyan Silyavski]

Neale,
your solution seems much better. I was a bit confused about that particular solution. Too much electronics and chance to mess.

but there still seems to be a bit of a debate about how much the squaring operation needs to be done, and whether you can't do it manually almost as easily.

I thought so before, but not now. Every reset with steppers results in a positional error. Yeah, for a wood working machine not a big deal, you can adjust from time to time by hand against hard stop. Not so for a more serious machine where more precision is required.

[Neale]

Thanks for the comments. My existing machine is pretty poor anyway, but only has a single X motor so I have no personal experience of the positioning issues and it's interesting to hear what problems other people see. Nearest I get to it is my 3D printer which uses two motors to drive the Z leadscrews; those motors are just wired in parallel from a single driver and within the tolerances of a 3D printer, I have never had any problems with drift of home position between them. However, it's all a bit different with two drivers/two motors, of course, as the drivers themselves can theoretically get out of sync with each other at the microstep level.

Anyway, I quite like the idea of grafting in an Arduino-based solution - I've done a bit of work with them both as the 3D printer controller and programming the microcontroller itself to use on a bare board. I'm sure that that could make quite a neat solution.