Just add bearings and screws (I used the ones from the Printrbot spool coaster kit).

Print 1 set of sides, 1 set of bearing posts, and pick the bottom size that's corrector for your spool.

I added rubber feet so as to not scratch up my desk. Perfect for the excellent Bukobot printer since it doesn't ship with a spool solution.

(Check back; I'll be adding different width bottoms as I come across different size spools.)

I printed in PLA using .15mm layers and a 40% rectilinear fill.