Robo3D Top mount spool holder Remix

Update: A full redesign with lots of extra functionality is up here:
http://www.thingiverse.com/thing:2010618

Bearing smooth, adjustable width top filament feeder, based on an elegant design by sadahisa. I included both a solid and an open version that uses less material.
https://www.youtube.com/watch?v=wYxuVQTHQLE