TL;DR

This is a WobbleX WS8 interface adapter for Prusa Mini. To install it, you need an additional 2 square nuts and 2 M3x8/M3x10 screws. No other modifications are needed, and it clears the Z brace I installed (caution required, spacing is tight). There're two pieces, to print them, use PETG or something better, no support required.

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My Prusa Mini developed some Z wobble issues. I honestly don't know how this is supposed to happen, as the Z carriage is guided by two smooth rods, any wobble shouldn't affect the print head. Anyway, the problem seems to be that my Z motor lead screw is slightly tilted. However, after cleaning the lead screw, shimming the Z motor to get it as square as I can, Z wobble reduced but were still present. Then I came across WobbleX, which claims can eliminate Z wobble, so I decided to give it a try. The WobbleX WS8 adapter provided by MirageC79 on GitHub does not fit the Prusa Mini due to the close spacing between the two Z axis smooth rods. It has to totated by 6 degrees to clear the smooth rods and leave room for the mounting screws. After installing it, Z wobble indeed disappeared, though some layer inconsistancy remains. 

To install it, jack the X axis up, undo the two screws securing the Z motor, the two screws securing the T nut under the Z carriage, lift the Z motor up a couple of centimeters and remove the T nut. Then install the top interface using the two screws originally securing the T nut, slide in the WS8, then the bottom interface, then the T nut. Use two M3x8/M3x10 screws to secure the T nut to the bottom interface, don't do this before the WS8 is properly sandwiched, the bottom interface cannot rotate freely as it won't clear the Z axis rods. 

If you have Z brace installed, make sure the assembly won't crash into the Z brace. I tested it on my machine and it just clears, so be careful.