This spool holder doesn't need anything else but a spare 8mm rod piece. It has a very smooth and precise movement although it doesn't use a ball bearing.
I added several models of claw caps and you can cheese between them according to the size of your spools. They usually click into the holes and require no glue to keep them into position. After you finish the spool, you can take off the claw caps and install them to the new spool.
One of the claw caps is supposed to rotate one way and the other one is supposed to rotate the other way. Pay attention to the direction of rotation and have them mounted as in the picture. Check the video for more details.
After you print and install this spool holder don't forget to post pictures :) .
-3 top layers
-3 bottom layers
-0.3 mm layer height
- PLA (ABS would crack - do not use ABS)