Adjustable Spool Holder - 608 Bearing Based - With Adjustment Knobs

Yet another spool holder, sure there are other designs out there but I just had to design my own. What sets this one apart? Knobs. No screwdriver required for adjusting the width of the spool. Designed to accommodate the various spool sizes I've encountered so far (Printrbot both 1.1 and 2.2lbs, Seacans, and Filaments.ca).

Utilizes easy to find 608 bearing (skateboard bearings) and about $5 worth of metric nuts and bolts.

Hardware:
Four 608 Skateboard Bearings
Four 20mm M8 Hex Bolts (M