Singer 221 Bobbin
thingiverse
I've tested this bobbin for a Singer 221 and it works. To assemble, apply some quick-drying glue to hold the two pieces in place - we use Kola LoKa (Crazy Glue) in Mexico, but you may have something similar called Loctite 495 in the USA. If there's a way to improve this design, feel free to share your feedback and I'll do my best to incorporate it.
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