Originally Posted by
Farmhousesewer
Singer 66s were made from 1902 to 1955.
On the second one the number 6s are different! Definitely strange. Sorry no answer for you.
I downloaded all of the singer numbers from the database and wrote a computer program to check for possibilities among the SNs. Nothing hit that was reasonable.
Keep in mind these are treadle machines in full cabinets (the kind with doors that look like furniture, not desks) and I don’t see any evidence of motors so my guess is that they are pretty old. I just don’t want to try to pry the SN plates off them just in case it damages the machines.