Want non-standard sized bobbins? Pull up the .scad file in OpenSCAD and change the dimensions to your heart's content! All of the following dimensions are adjustable:

• bobbin height
• bobbin width
• bobbin thickness
• width of the “arms” at the top & bottom
• depth of the indent on the sides

Bobbins also have three design features that can be turned on or off by clicking the appropriate checkboxes in the OpenSCAD customizer:

• slots for floss or yarn at the bottom of the bobbin (slot width is adjustable)
• hole at the top of the bobbin for e.g. hanging on a binder ring (hole radius & placement are adjustable)
• triangular cutouts to reduce the amount of plastic needed for printing larger bobbins

Uploaded STL files are provided for a “standard” size embroidery floss bobbin (approx 38 mm x 38 mm x 1 mm thick), and a couple of larger bobbins sized to fit in LuckyResistor's stackable storage boxes (available here) as shown in the uploaded photo. But really, you should just download the .scad file and make whatever dimensions you want :-)