Skipped layers

[Reaping miner]

On the prusa i3's I have observed this problem happening from the threaded rods for the z axis passing through the small holes at the top of the frame. The threaded rods are just that. They are a far cry from the precision cnc smooth rods that the bearings ride on. If you hold the bottom and the top of the threaded rods in a fixed location, then the layers of your print can only show the out of round shape of your threaded rods. Cut the threaded rods just short of the top of the frame so the only thing the rods can touch are the stepper motor and the nut they spin through. As you make your next print, you can watch the top of the rod and see how far out of round it really is. And then you will see your good print quality

I simply bought a set of leadscrews, couplers and nuts. No Z-wobble anymore. I do have skipped layers on Z-hops again but thats because the Z-wobble from before screwed up the X-axis ends i needed to print (Very tight tolerances on those designs), causing my binding-sensitive RJ4JP bearings to bind on the Z-axis again.... (Actually visible compression and extension on the couplers when changing Z directions now). Trying to print a compatible X-axis endstop holder again first. (Without Z-hops ofcourse.) Then i will probably look into new, more suitable bearings for the Z axis or redesign the X-ends. RJ4JPs are just a huge pain in the ass to set-up. They are either too tightly conencted and bind, or they are too loosely connected and have play on either the inside or outside of the bearing.....