UC300ETH: UCBB Vs UB1 breakout board ?

[JAZZCNC]

Hang on. Is this any different to how I have been running this machine for several years? I have 2 identical stepper motors wired the same way to identical stepper drivers. They have their own step/dir signals but as these are slaved they should be the same. When I first built it I aligned the motors to full step with loose couplings and have not touched it since. Z axis sounds smooth as the day it was built. Only difference with the update is running off the same dir and step outputs.

If you haven't been homing each motor then Yes, it's exactly the same. I can't see how the motors won't have jumped in opposite directions at some point and if you haven't got reference marks to check against then it could be very hard to see. It would be a random occurrence and you could have just been lucky that it's not twisted up enough to show up.? Still, it wouldn't be my first choice if I'm honest.!

[routercnc]

@dazp
Wow that is busy ! Funny how you always seem to need more space than you originally think.

@Dean
I hear you. I might have been lucky all these years but I could always add a pointer on the rear output shaft of each motor and periodically check they are in the same position after homing.

[Kitwn]

If you haven't been homing each motor then Yes, it's exactly the same. I can't see how the motors won't have jumped in opposite directions at some point and if you haven't got reference marks to check against then it could be very hard to see. It would be a random occurrence and you could have just been lucky that it's not twisted up enough to show up.? Still, it wouldn't be my first choice if I'm honest.!

Surely the mechanism will relax mechanically every time the machine is switched off and turn the motors back to the same starting positions. There may be a small twist at switch-on but it won't accumulate over multiple on/off cycles.

routercnc,
Thanks for the reminder pictures.
Sounds like you're talking yourself into a redesign to have a single motor and belt for Z as you have for X (or s it Y?). Was there a good reason for not using the same technique?

Kit