JMG123's remix of Airtight filament delivery system

This is a remix of stephenmhall's "Airtight Filament delivery system (almost) " Not that there was anything wrong with the original, I just had an excess of 3mm hex bolts lying around, and no 4mm's that the original needed. I also wanted to have the filament coming out of the side rather than the top so that it is easily stackable.

I designed a bracket to hold an off cut of old broom handle in the middle of the box. The spools sit on this rather than the base of the box. It also allow me