Not sure if this would be best in the 3D printer section or here but I thought I would share this bobbin rack case that I made up today. I have attached a stl file so it can be printed out if you like. I used a 20% fill with .8mm shell thickness settings on the printer. It uses 108 grams of filament at that and in Oz that's about $4.00 worth. It holds 49 bobbins and the L is 172mm x 125 W. The hole size for a bobbin is 12x23mm.
BOBBIN CARRIER.stl
2mm thick base
The hatch area