Recently, I bought an old Singer treadle machine. It appeared in good shape, but had no belt or attachments.
I walked through an identifying website, which said it was a Singer 66. So I bought parts for the Singer 66.
A couple days later, I started to wonder – ran through the ‘test’ again, but came up with a Singer 15 class.
The bobin that was in it ISN’T of the 66 class. It is slightly smaller, and appears to be a perfect match for the Singer 15 class.