Originally Posted by
grant15clone
My understanding on this is, There were two different hook assemblies made for these machines with just the slightest of differences between the two. I will call them "A" and "B". Design A can work with both A and B but Design B will only work with B. There is no good way to tell them apart either AND the new replacement ones do not fit all machines correctly. Buying an original would be the best way to find one that would fit and work in your machine, but I would want to try it in the machine first before buying it.
~G~
Grant,
The hook and bobbin case for 221s and 301s are the same. It's the bobbin case
base that is different and not interchangeable. If a machine has the wrong base in it no bobbin case will work properly. It's quite possible that someone at some time replaced Nancys' with the wrong one. The vintage Singer groups are full of these discussions. People think that because the machines use the same bobbin case that the case bases are the same when they're not.
Cari