I had a problem with loops of filament. I figured a cap would help. I did one previously, but the tolerances were way too tight. It did, however, work! I can't afford to spend the filament on this one until I re-up. The tabs were started in FreeCAD, bent in Blender, then assembled with the base in FreeCAD. It was mostly intended to be a learning process. Not entirely sure the tabs will be effective. I tried to size things so that it can be adapted to different kinds of spools (that have less than 200mm OD). Might want to print at an angle and use a more flexible filament. On my end, a reasonable print would be about 2.5 hrs and use ~90g. I'll print one when I can and upload the result.