This assembly allows the use of a spiral cut coupler on the z-axis. It uses a thrust washer assembly to eliminate leadscrew end-play, and otherwise corrects wobble in the z-axis.If you own a Prusa, then the assembly is fairly straight forward. You will need to purchase a few items as follows:1) Spiral cut coupler. You need two.2) M3 x 50mm socket head screws. Easy to find online. You need 4pc.3) 8mm I.D. thrust washers. McMaster carr P/N xxxxx (or print one) 2ea.4) Depending on the length of your current lead screws, you may need new ones. I didn't, but it was close. -Disassemble your machine and install parts in order as illustrated. -Use washers on the 50mm screws as needed. -Keep the whole assembly loose and separate the motor and spacer with a couple of business cards (up to 1mm thickness). This will put some necessary preload on the spiral cut of the coupler.-Use some moly lube on the clamping fasteners to allow even torquing, and tighten them with a high quality hex-wrench. You may want to also use thread locker, or epoxy glue on both the lead screw and the motor shaft to ensure no-slip._Finally, remove the business card shim from the assembly and tighten the 4 long screws that hold it all together. It is important to keep an eye on the spiral cut. It should collapse just slightly, but not totally! That is very important.Unfortunately, I do not use openscad. I will start with .stl's and if that won't work, let me know. I use solidworks, but can export several formats... just not openscad:(