I am building a new printer and am trying to be as precise as possible. I have purchased a set of lead screws and nuts from trinity labs. They and 10mm thick and are perfectly straight. When I put together one side of the z axis and ran the stepper back and forth, I noticed some z wobble. In addition to the x end wobbling, I could see the lead screw wobbling near where it entered the coupler to the stepper. If I disconnect the lead screw, I can see that just the coupler alone wobbles. It is not as obvious as the wobble on the lead screw because it is not "amplified" by the length of the screw.
The coupler I am using is of those aluminum helical couplers, also purchased from trinity labs, and it is supposed to be machined exactly for a 5mm shaft and the size lead screw I am using. I think my problem might be due to the fact that the motor shaft has a flat ground into it. I do not think they coupler is going on correctly, and I think they set screw is pushing it out of alignment. I made sure to tighten the screw against the flat, and not the round side of the shaft, but I still see the wobble.
I've tried a printed coupler using heat shrink tubing, but I still got wobble.
As of yet, I don't have a solution, but I will keep at it.
