DMC Swatch Bobbins
Step 1: Print 500 of the bobbins (dmc-swatch-bobbin.stl) on the 3d printer of your choosing. I had the best luck prining them on their sides (long narrow side to the bed), with supports underneath.
Step 2: Glue a magnet into each one. The wells on the back are sized for 1/4" x 1/8" x 1/32" thick magnets. I got mine from KJ Magnetics.
Step 3: Print labels. If you have a Silhouette Cameo machine you can use the included labels-all.studio3 file, making sure to print each page with registration marks on and the 'cut lines' layer off.
Step 4: Wind each bobbin with floss. Secure with a dab of superglue and trim excess thread.
Step 5: Apply label and enjoy!