Filament spool shaft ball bearing support (Samla project)

I'm building my filament dry box and I need a decent spool shaft holder.
I've saw this holder https://www.thingiverse.com/thing:2198955, but I doesn't like the way him inserted the BB into the ball bearing, too dangerous for 3D printer nozzle.
Casually discovered this project https://www.thingiverse.com/thing:1799757 that is a great idea (make a hole to insert BB's), so I drawed a new holder, merging the two ideas, to fit my needs.
The central hole is designed for aluminium shaft of 23,5 mm that is commonly found on hardware store in Italy.
The external diameter fit on spool with a hole of 50 to 53 mm.
NOTE: put only 16 BB's on the ball bearing, otherwise it do not work properly

Update 2018-02-12: I bought some spool of Anycubic PLA that have a hole of 58mm, so I draw an adapter. This one is slightly conical externally, so it will fit from 56 to 59 mm.