I designed this as a companion to my YAFSH (Yet Another Filament Spool Holder) but it will also work as a standalone for your own filament holder. It was designed specifically with the MakerGeeks reels, but as it is, it will work with any spool that is 67mm thick with a 57mm inner diameter opening. There are two versions. The original version utilizes the bearingSleeve-center and two of the bearingSleeve-endcap_x2 models. You can size the outer diameter of the center piece to fit your particular reel if necessary. The second version utilizes two of the bearingSleeve-standalone_x2 models only. You will have to resize the inner circle if your reel is a different size. In my mind, the draw of the first version is that there is inner support for the reel as well as a central object against which you can snug the nut without the risk of deforming the reel. It's also simpler to resize the first version for various reels than the second, in my opinion. The choice of which to use is, of course, yours.
In addition the printed pieces, you will also need the following hardware:
12mm-1.75 x 140mm bolt
12mm x 26mm washer x2
Toro 110513 (Stens 215-211) bearing x2
I chose the components because, as a mechanic, this is what I had available in my shop this weekend. The bearings are 0.75" inside diameter; 1.38" outside diameter; 0.495" height. This particular bearing, however, also has two non-standard features which made it the perfect fit for this project - 1) there is a small (1mm) lip on one side and 2) there is a small (2mm) lip on the outer edge. Standard bearings without these lips will NOT work with this design!
Post-Printing Make sure that the bearings are pressed into the endcaps with the lip facing TOWARDS the printed piece. the parts are assembled in this order - bolt; washer; bearing/endcap assembly (bearing facing OUT); center; filament spool; bearing/endcap assembly (bearing facing OUT); washer; nut. When used with my YAFSH, the lips on the bearings rest on the INSIDES of the uprights.