Filament Spool Holder Adapter

I was having trouble feeding some inexpensive(very) PLA filament, in which the extruder had trouble pulling the reel forward due to how much larger diameter the reel hole is with respect to the Wanhao Duplicator/Monoprice Maker's spool holder arm.
I created a fresh OpenSCAD file to fit the spool holder arm.
This was Inspired by the T-Slot mount spool holder by npushis https://www.thingiverse.com/thing:70275.

Both the inner diameter and outer diameter are customizable, and I have had great results so far. My inner diameter ended up being just a bit too tight, but I was able to shave out some of the plastic with a pocket knife, and make it fit.
The adapter hubs fit snugly on the spool holder and do not rotate, but the filament reel freely rotates about the hubs. I positioned the hubs with about an extra mm between themselves and the reel to avoid adding extra friction.