VoilÃƒÂ , here is the my version of a dispenser for filament spools made from printed brackets and wheels, together with some leftover M8 threaded rods and a couple of 608 bearings, and a toothbrush to stop the rotation softly.
This design is easily adaptable to different size spools (as long as the centre hole is 51...59mm).
The picture of the assembled dispenser shows that the wheel does almost slip inside the spool, so I changed the outer diameter in order to avoid that issue. The wheel has now a small diameter of 50mm, and the outer diameter is now 60mm.
I added another picture showing a "lightweight version" for a BFB filament spool. When I received and assembled the RapMan kit, I was not so impressed by the original laser cut design BFB provides as it it quite wobbly. I modified it using my bracket+rod design and kept the 2 acrylic discs as the inner diameter is >60mm. However, I made sure the discs do have clearance to rotate smoothly (spares you the need for bearings). Again, I used a toothbrush to stop the spool from rotating too much.