Large spool roller for 3Kg spools, completely printed.

Find the rollers / bearings here:
https://makerworld.com/en/models/1753273
You will need 4 rollers / bearings.

The rails and pins to secure the bearings to the rails are my own design. The pins hand press in and can be easily removed. They should be strong enough for a 3Kg roll, especially considering 4 of them share the weight. The rails have cavities that I intended for inserting magnets for more stability if it was on a metal surface, but I didn't end up inserting them as the holes were slightly too tight, so I have removed the pause for that. The little grooves on the bottom of the rails were in case I wanted to add some silicone sealant, E6000, shoe goo, or something else to add "grip," but I didn't end up using them.

I originally intended 6x3mm or 10x3mm magnets, so if you have like 5x3mm or 9x3mm... maybe they will fit fine?

As the pins are easy to remove, you can space the rollers closer or further apart for different spools sizes. I don't think it would be necessary to do so, but its possible. If you want to use real heavy spools or are rough with this, the pins could break. You could always try to print them in a different material such as PLA+, real hard TPU, nylon, etc... or model a different pin with different retention mechanism... or even use metal like a bolt.

In the print profile, the rails also have modifiers to increase the walls from 2 to 3 and infill to 25% and 50% in proximity to the axel pin holes for more strength. So I'd recommend sticking to the print profile unless you are going to really up the walls and infill anyways or you want to do modifiers differently.

I have included a .step file for the rails and pins for ease of editing should someone want to modify them.

I printed it all in Bambu PLA Basic. No support.

0.4mm noz
0.2mm layer standard

rails:
2 walls - except 3 per modifiers near axle pin holes
15% gyroid - except up to 25% and 50% in proximity to axle pin holes via modifiers
no support
no brim

pins:
3 walls
35% gyroid