I was having problems with the original design from BPopilek, where the spool would randomly fall off the holder.

So I edited the design, and made make it longer, so the spool would have a better center of gravity, and not fall off the holder as easily.

I made two versions, one where I added 20mm of length, and another with 35mm of length. Either one should work fine. I just designed the longer one for the added security.

The bearings can be purchased here: (You will need 2 sets)
http://www.amazon.com/gp/product/B00DPH8M3C/
http://www.homedepot.com/p/100574233

Original Design
http://www.thingiverse.com/thing:433143

Select a version (either 20mm or 35mm)

BOM:
2 x Brackets
2 x Spool Holder (20mm or 35mm)
2 x Sets of Bearings (4 Bearings Total)