Simple spool holder

I created this to simplify my spool holder. The stl is perfect for my spools, using 624 bearings, and m4 25mm fasteners.

I was inspired by markab's design, but couldn't get his scad/stl output to slice correctly, so whipped up this simplified version.

Feel free to add improvements, either here, or on github: https://github.com/blackguest/models-spool_stand