Summary

This is a simple hub that lets you press-fit a skate bearing into it, to mount on a 5/16th threaded rod, and provide a much lower friction filament supply than just putting your spool over a toilet paper holder or a piece of PVC.

Instructions

The part should be about right to press over a bearing ring with a vise, or just with good pressure on a solid flat surface. The four little nubs on the inner perimeter are on purpose for a good friction fit.
The outermost diameter should fit into the 'stepped' portion of the spool ends for the filament spools from Solidoodle. The longer extending cylinder should penetrate into the spool a bit further.
I print two of these, a couple of flange pieces for atop the PVC extensions (see pics, to be uploaded soon), and use a piece of about 12" 5/16 x 18 threaded rod with nuts and a couple washers to create a great freespinning filament supply for my Solidoodle v2.

Filament spool bearing-ring hub