>>2925262
I was thinking the same about those rings being the insides of the bearing. I thought they were seized onto the shaft but they just came off a few hours later. The shaft itself is, well, shafted.

And yeah this thing ran long after it failed, and i'm pretty sure it was going bad for quite some time prior to that but not as catastrophically. It ran overnight after I started hearing the noise. At the time I thought it was some piece of plastic or something stuck on the gantry or the print head rubbing the top of the print. I knew the idler was on it's last legs but didn't realize at the time how bad it was and figured it could wait until I finished what I was making.

Anybody know what this kind of bolt/screw is called?