Oh my goodness I just spent hours playing catch-up,what a wealth of information here.
Huge thank-you to all of you for sharing your knowledge of vintage machines.
I have a 1948 15-90 singer , singer 1897 treadle, singer 99-3 & 2 Kenmores that I am not sure of exact dates. My latest is a WIP as I am told its a badged National, I want to turn her into a hand crank but am told probably can't do that unless I find another National for parts.