My first attempt is fused together. I've managed to loosen the center gear, but the planetary gears around it are another story. I may have to play with settings to get this thing to print in a workable condition. Probably going to stick with paying a buck or 2 for steel bearings instead. Edit May 1, 2017. After a bit more play, okay an hour or two over several days, the planetary gear are free and it rotates. I have it spinning several full rotations, so that's cool. If you print this and it seems stuck or fused, just wriggle the center gear back and forth tangentially to the gear. Then try rotating it as you would expect to force the other gears. Despite its inability to spin like a true ball bearing, it does work and is quite imoressive.