About this 3D model

12/20/2013: Don't use this thing, use this one http://www.thingiverse.com/thing:22422 I modified the SCAD file to have 0.5 gap sizes and a z_rod_r of 7/2 instead of 6. I also need to enlarge the 3mm nut and screw holes but I really like the design. ----------------------------------------------------------- Update, the fixed file has been uploaded, sorry for the prior issues. Update: Apologies, not sure what happened to the V2 file to make it corrupt, but I will rebuild and re-upload this evening. I have removed it to stop anyone else from wasting their time. Update: I added setscrew to the motor shaft end. The vibrations would walk the Z axis down slowly. This stops that. I also make it smoother to take advantage of Sprinter's speed. The old version: I edited the coupling.scad file to increase the outer diameter and thus wall thickness of the part. I also added hex recesses to capture the nut for the clamping screws. I had issues with the originals splitting. I think it's because I used PLA (I only use PLA) so you may not need this for ABS.