Anti-wobble Z-coupling (for Mendel-Prusa)

Z coupling 5 mm -> 6.35mm (1/4"), customizable in Customizer.

Lately I got obsessed with the z-wobble in my MendelMax 1.5. I already have precision lead screws and didn't want to buy new ones.
I noticed that the motor axis was very stable, but the lead screw itself was wobbling at the couple location. I thought that fixing that wobble may improve wobbling in my prints, and it did!

Based on the z-coupling by nophead/Griffin_Nicoll, I updated the model with an adjustable asymmetry. I assumed that the asymmetry is mostly in a single direction. It also has some visual updates and I made it a bit longer to enforce more straightness. This version works with m3 screws and bolts.

The grey object has near no wobble, while the orange object still has some wobble.

Instructions:

• Move head up and down with straight coupling. See if the axis goes back and forth (seen from the side). If so, an asymmetric coupling may help.
• Try values of for instance 0.3 mm and see if the back/forth movement is less or worse. If worse, rotate the coupling and tighten again.
• It's a lot of experimenting to find your optimal setting.

I ended up with:

• One end a straight coupling
• Other side has a 0.3mm asymmetry

Note:
z-wobble can easily be confused with z-ribbing. I fixed my z-ribbing by adjusting the steps/mm in my firmware by a tiny bit.
Original value 2015.748, new value 2020 -> This ensures that all layer thicknesses that are multiple of 0.05 have the same amount of motor steps through all layers.