It's not the Z Rods(?)

So, upon receiving new Z rods for my KE from Creality I started the process. When I was raising the gantry I noticed the base of the (right) Z rod was wobbling. Now it isn’t the rod itself, it is the coupling. I don’t know it that coupling is called but you can clearly see in the video it is not rotating symmetrically and it’s affecting the rod. There is a distinct “wobble” or lopsidedness to it. At the end of the video you can see the result. NO adjustments help. Not lead screw nuts, not belts, not temp, not speed nothing. Here is the video: https://youtu.be/M69fpesvR5U

NOW WHAT?! :weary:

It looks like the outside of the coupler is not as round as the inside that holds the Z lead screw.

Keep in mind the Z lead screw doesn’t move during layer printing unless your bed is off-level or z-hoping. Then, the printer’s software will move it slightly and not a full turn.

@Lensman showing us a current print with the artifacts would help.

Are the leadnut screws on the X gantry too tight? They are supposed to be a little loose to compensate for any leadscrew imperfections.

Sure thing. Below please find a bunch of test images. The ones with numbers best illustrate the inability to print “smooth” with various adjustments. Note that while image #1 is the best result it does not clearly show the banding because of the light angle. All combinations of speed/temp have been been exhausted. Z hop vs no Z hop. Different brands of filament. Filament on and off the holder. Structural screws tightened. Belt tensions from full tight to loose…







There is also the latest test print at the end of the video.

Unfortunately all combinations of tightening have been exhausted. While some yield “better” results, there are no prints that are acceptable without the lines.