Bearing Spool Caps for Roller

I made these for smooth rolling of the spools on a standard 8mm rod within a dry box. I haven't finished the complete setup so no photos but they fit the Overture PLA Pro spools that I have really well. Likely will need slight modification for varying brands as the center ID can vary. 

They work with a standard 608 bearing. So will need two bearings and two caps per spool.