Summary

/!\ BEARING ARE OPTIONAL /!\

Hey! I figured out that not every spool have the same width and that's why my design lets you adjust it for a perfect fit!

I will print it soon and test it. Still working on it!

UPDATE : I printed it yesterday (09.04.2015) and tested it. It works very well. As espected. I did some improvements for a better user experience.

Why it's interesting ? Well, thanks to the bearing, the spool gives no resistance. And it's adjustable in width. Finally, I think the small size and simple look is a plus.

Note : To complete the build, you will need 4 bearing with an internal diameter of 8mm (don't worry about the external diameter, it's okay!)
Note 2 : I figured out that bearing are "optional" because the resistance between the spool and the Universal Filament Holder is very low.