Maker Box 1.75 Filament Spool with Inserts

This my version of a sample filament spool for [Maker Box](http://makerbox.me) that combines what I liked from some other spools, and adds a design element of my own. This is the fifth (and hopefully final) revision I've gone through.

The main components of this spool are printed in two parts, with a large threaded center that allows them to be securely connected, and later re-used. You can lay the filament sample in one half (the spool bottom), anchor one end in the provided 60 degree hole (