Reddit reviews 10 pk Metal Bobbins 45785 - Singer Featherweight
We found 1 Reddit comments about 10 pk Metal Bobbins 45785 - Singer Featherweight. Here are the top ones, ranked by their Reddit score.
Most low-shank feet will work for the 221, so you should be able to use a cheap low-shank walking foot if you want to play around with it.
But universal bobbins will not work for it, you really need featherweight bobbins - they are thinner than most others.