608 Ball Bearing

This is a modified version of
http://www.thingiverse.com/thing:4676

The design was first improved so I could press 4.5mm BBs into it without breaking anything(A 4mm hole was cut between the inner and outer races).
Then I found that I could almost fit 11 BBs inside, but the fit was a little too tight. So the inner and outer races needed to be slightly enlarged. The OD is still 22mm and ID 8mm.