Filament roller holder.
To keep center of mass on middle and make rotation more easy
No, printed bearings , just filament print with some inner offset.
You can print with no infill.

• 4 layers to Top and Bottom and 3 or 4 walls
• 5h to print,
  Settings:
• Material: PLA
• Hotend temp 205°,
• Bed temp 60°
• Printing speed 60mm

Creality

Ender 3

No

No

200