This is a derivative of:
thingiverse.com/thing:4337 by randyy
There were several things I didn't like about this. The first is the spool was too small, so my filament would just unwind itself. The second was that I didn't have any rods to go between the spools. Finally, the hole in the middle was too small for the rod I wanted to but it on.
So what did I do?
Made it extend-able, so the size of the spool can be changed.
Made the center hole bigger.
Made it so I could attached printable hooks to hold the plastic onto the spool (and made them double, so that it would hold more plastic!)
AND, to save myself some plastic, I made the ends with connectors so you can attach them and hopefully get more plastic onto less spools.