Yet another customizable bearing

This is actually my yesterday's evening-hack. It's redundant, because there are many bearings in thingiverse and it's of no use because I have loads of proper cheap Chinese metal bearings of different sizes and I guess that you have some, too. I just made ist to distract me from some other project, a heat-exchanger. Anyway, I share it for fun. Maybe someone likes the look of my rounded edges or maybe someone gets some inspiration from the code, like not to work with the basic object directives s