Hayoo, printed out the original ball screw for the 625 bearings. The rod spins really nicely on it but I have to get the rod cut before I can tell you how well it does. Going to try using it on the z-axis for the solidoodle, will report back. Two things though:
1: I had to print it at 102% the size, did anyone else have to scale it or is that a calibration issue on my end?
2: Is there some significance on why the center hole for the smooth rod is covered at one point?