Double ball bearing spool holder (colorfabb, esun, SOVB, Neofil...)

The principle consists in replacing the threaded rod and the nuts by an axis of diameter 8 and two tips adapted to the diameter of the spool stand. Next, two central double-bearing hubs and specific adapters will allow to use almost all brands of filament spool.
For the central hubs, I use 608ZZ bearing (the same for rollers and skateboard).
The axis and tips are dimensionned for WEASY spool stand, and the adaptors for Colorfabb, Neofil, SOVB and Esun spools.