If you're interested, saw some old Singers in Englishtown NJ antique/junk store
There were 3 Singers - one from around the 70's +/- a decade, one that looks like a 50's singer to me, and one that looked older than both of those. There was also a Kenmore, probably from the 70's/80's. Mind you I'm guessing about ages...
I didn't buy (or try) any of them, but the wheel on two of the Singers turned, the '50-ish' model looked very good, the 'newer' one was plastic and the bottom of the plastic was separating from the top. The oldest Singer was impossible to look at, just saw the antique cabinet, which was in fair (not great, but I've seen worse) shape. The Kenmore looked like it was in pretty good shape considering it's' age, and the wheel turned freely.
The antique/junk store is in the middle of Englishtown at what years ago used to be an IGA grocery store. Warning - if you're going to see these, be prepared for a complete mess, and you will have to ask someone to show you where they are (or spend considerable time looking for them) and to get them someplace you can take a thorough look at them. If I had a need or desire for another older machine, I'd have checked them out more than I did. In any case, the store is interesting/fun to browse through and I have found some small, non-sewing related 'treasures' (to me!) at very good prices. A second warning - the place is a fire trap and I have no idea how they manage to stay open. Wear a coat, because heat in the place is either set very low or not on/working at all!
Did I mention that I love to go to this place, have been visiting it periodically for years and don't know what the business is called?