Solidoodle 2 filament rollers - remix for common bearings

I like Eobermeyer's original design, but couldn't find the bearing size it is designed for. This design uses standard 608 bearings because they are cheap and sold everywhere.

*Notes*
Update: After using this for months, I noticed it doesn't work well for thin, tall cardboard filament spools. They don't roll as smoothly as wide or plastic spools and I had one fall off.
1. The original design used a 1/4" steel rod but 608 bearings have an 8mm core. A 5/16" rod will fit these perfectly or us