Singer is still in business I believe. The model I have was designed in 1929. I'm not sure how long they built it and how old mine is, but just looking at it you can see it's very old. I wouldn't be surprised if it's from 1929 or the early 30's. It's had to have seen tens of thousands of hours of industrial production.
One thing about clutch motor sewing machines is that they are very powerful. The motor runs at full rpm's all the time. The treadle controls the clutch and if you fully engage the clutch immediately it asserts a lot of torque. Before I modified mine, it sewed 75 stitches PER SECOND.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13