This bearing has an outer diameter of 51.5mm and an inner diameter of 8mm, making it perfect for making a resistance-free spindle out of an 8mm bolt, for example the one from the stock Rapman spindle. The outer diameter fits perfectly in reels from orbi-tech.de and the photos seen here are made using their amazing custom PLA mix.
This is also just a fun piece to print as it spins freely with hardly any cleaning up!
2015-02-10: Added version with 59.3mm outer diameter
Use Skeinforge support at ~20% density and let it do it's thing! Took me less than 10 minutes to clean it using only pliers and side cutters.
(Rapman 3.1.1 used to create this thing)
NOTE ON BFB FILES:
orbear2.bfb is only for printing PLA on a Rapman 3D printer.
orbear2abs.bfb is only for printing ABS (thanks Grok!)