Multi-size Spool Tri-Adapter Roller Axle

... I give you the Tri-Adapter Axle.

I started by measuring the inside diameter of the spools that I had. I came up with 4 common sizes, all included in my design. ~~I haven't found a spool (yet) that doesn't work.~~

I used a 3D printed angle bracket for PVC that I made and some PVC fittings to mount it above my printer. With [3/8" ID bearings](https://www.thebigbearingstore.com/r6-2rs-r6-zz-radial-ball-bearing-3-8-bore/ "Bearings") that pop into the Tri-Adapter body, the whole thing eas