Simple filament rack. Requires two sections of dowel and four #8/4.5mm screws for installation. I used 1" screws to install it into ¾" plywood.
I've included the f3d file in case you want to adjust the dowel diameter. This is for spools of diameter 20mm, but that can also be modified in the design.
Designed to be printed at 0.2mm layer height. I printed with 20% infill and 4 perimeters.
The author remixed this model.
Remodeled the design to use dowels of narrower diameter. Also caps the sides so the two racks hold the dowels in place.