Y Axis stepper motor has slack

Was looking into doing the X axis stiffening mod as I have some nasty chatter on the x axis, especially when moving to the right. I noticed that when the power is on, i can move the right Y axis stepper motor by hand about a 1/4 of an inch, while the left stays put, and also the X axis makerslides aren’t parallel (the right side is about 4.5 mm and the left side is about 3.6 mm). I assume I’ll need to drill through the makerslides and add the aluminum bar.

Here’s a video of the movement. The power is on.

Any idea why the slop in the right Y axis stepper motor? I’ve got the NEMA 23 motors.

Hi @ScottWolz, the video didn’t work for me, but maybe its on my end :scream:

My instinct would be to check the pot for the specific motor you’re seeing backlash in because typically the more current supplied to the motor the higher the no-load or holding torque should be if I’m not mistaken.

Thanks for looking. I’ve reuploaded the video so you can see, but I’ll check the pot when I get home and let you know how it turns out.

So, I’ve got it pretty much fixed. First and foremost, the set screw in the pulley was loose, so obviously there was slack there. Secondly, the belting was loose on both sides, but especially on the right. With a little heat shrink to tighten it up around the clip, I’m off to try tackle the next issue.

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Pulley screws is what first came to mind for me. Something you can do to identify it easier should it happen again is to use a fine sharpie and make a line across the motor shaft and onto the pulley to see that they are turning together or slipping in relation to one another.