Z axis loose on bottom - tight on top

I’m running into a new issue on my machine. Right now as the Z axis travels up toward the upper 1/3 it starts binding and slipping teeth on the belt.

I adjust the tightness of the eccentric nuts on the Z axis carriage at top to loosen it and then as it travels down it’s too loose.

I am racking my head to figure out what could be causing this.

Any thoughts on what to look at?

Thanks - that seemed to help.

It still is binding a little at the very top - but not bad

It’s skipping teeth in the belt when it moves to top inch before the home switch.

The carriage wheels on top are too tight there, but I don’t want to loosen the fit as then it gets sloppy towards the bottom.

I’ll see if I can take a video tonight.

Right now I’m just dealing with it as it only comes in play at machine homing, and I care more about not having slop in the carriage when cutting. But I would like to understand why it’s doing it and fix it for good.

Thanks for the help!

More likely the top bearing plate is either installed wrong or needs readjusted slightly. This can make it seem like the wheels are too tight.


Is it hitting the Dewalt housing? You’ve gotta carefully orient the Dewalt to allow clearance or scrap a little of the yellow housing off for a better fit.

It was the stop nut on top - it somehow became loose. I tightened it up again and it seems to have gone away