It sounds like metal shavings in between the rails and the part that slides on them. I can’t see anything, but I hear and feel the Z axis bind up and require force to move it up or down. I removed the lead screw and disconnected the Z gantry from the stepper motor to isolate the issue directly to the rails. Not sure whats going on, are there ball bearings under those red rubber parts?
I’m guessing this is the part I’d need? For the 30x30. If I understand correctly, quantity 1 comes with the pair of bearings?
It is hard to tell, but the rails look dry as in little or no lube, to me.
@Chaosweaver If you’ve never had any of the balls fall out, it may just be a matter of lubricating the linear guides. This should be a routine maintenance task. There are instructions on the Sienci site here
Seemed to work, dont remember seeing any lubrication in the directions before. I have one ball that fell out but really dont want to disassemble the thing again if its not a big deal.