Printrbot Simple Adjustable Spool Stand / Coaster

This is a modified version of Ramai's "Spool holder, Adjustable, from PB design." Requires 4 skateboard bearings.

If you are not limited to a 4x4 bed, then you may consider his design instead.
http://www.thingiverse.com/thing:178862

I wanted to be able to print this coaster on a smaller printer. Mine is a Printrbot Simple and it only prints 4x4x4. I'm sure the design can be improved but I made these modifications in under 2 hours.

I put screw holes in the fins and the coaster so you could securely attach the fins if needed. For now my fins are holding just by melting some of the PLA with a lighter and sticking the fin to the coaster. I had to melt some raw filament in some of the cracks between the fin and coaster, but they seem to be holding. I have made several successful prints with it.