Sturdy Filament Spool Holder

Wanted a sturdy filament spool holder that I could mount flush to a surface. I know there are a ton of these, but this one has been working great. Has only been tested with 1kg spools.

Press a couple of skate bearings into the Spool Holders. Run a 5/16" threaded rod through the tower with one nut pressed into the hexagonal recess and a nut with washer on the back to lock the shaft in place. Use a couple washers to keep the inner Spool Holder from rubbing. One nut on the end presses the Spool holders into reels with various size holes.

I used PETG but any filament will probably work.