Customizable Ball Bearing with Flange Generator

This is a customizable ball bearing generator. The main purpose for me was to make a pair of ball bearings to hold a Hatchbox 1kg filament spool on a half inch rod. The second purpose was to practice OpenSCAD programming. The body of the code was borrowed from http://www.thingiverse.com/thing:822960 but I wanted to achieve the look of http://www.thingiverse.com/thing:1570238. I think there are some weaknesses in thing:822960. For example, large flat surfaces make it hard to remove from raft. Als