PolyBox Extender (modified)

This remix imporoves upon turtlecreations design by further extending the height of the polybox, thus allowing for more sophisticated bearing solutions. It also adds support structures to ensure the lid does not bow inwards, thus making the enclosure more air-tight. Lastly the two halfs can now be joined by M3 bolts.

When using 3kg spools I strongly recommend ripping out the tiny wheels and bearings that Polymaker included and instead use this design: https://www.thingiverse.com/thing:1768975/files