The author remixed this model.
This is actually a variation of my own design, Printable Bearing, that I enhanced to replace the planetary gear that was used by Subtle3D.
I doubled my bearing width and added some additional thickness to the center wall of the bearing so that they would provide freedom of movement to the outer bearing wall. And, I designed it fit on a 8mm rod. There's plenty of room to open it up to fit a 10mm rod (you'll need to add a negative space modifier to enlarge that center hole).
I matched the threads that were used for the planetary gear so that the nut could be used.