butée à bille pour https://www.thingiverse.com/thing:2687075

thingiverse

Here is a ball bearing for my storage tower made with empty spools, you'll need 6mm diameter balls (pistol ball bearings), it turns much better like this. See here https://youtu.be/wAkBQFOD24s I've included the sources in 123d design and STL You might find that the upper tower is quite tall, if you make one for each spool, you'll need to extend it, not sure by how much as I haven't tried it.