This is a cone with a bearing inside to hold the filament.

The diameter of the coil is 40mm and the bearing is a 608zz the same bearing we use in the extruder. I use it with a M8 nut and a washer in both sides.

You need to print 2 cones

It's very simple but effective!

2x M8 nut
2x washer (M8)
2x 608zz (bearing)
2x cono rodamiento (3D printed)