My own design of spool roller.

I had a pack of skate bearings (Skateboard Bearings 608ZZ) and decided to make a spool roller around it.

Designed in blender, with almost zero printing skills and I was surprised it worked from the first try.

This is not print and use, requires couple of things to do, like gluing the roller halves together, inserting bearings, but nothing too difficult.

I was concerned that the pin on the rollers will be the weak spot (and it probably is, since the force is applied along the layers), but it still works perfectly fine.