Here is my reply to the same post in vintage section, which would be a good place for it, since it was made starting in 1959.
Originally Posted by
OurWorkbench
Since you say you are new to sewing, I would suggest if you want to go vintage that you look into some more common domestic machines. As bkay said industrial machines "are often single purpose machines" and consequently not for a variety of fabrics. Also since there are not as many industrial machines 'in the wild' the parts are more difficult to find.
According to ISMACS
comprehensive model list the 331K6 is
Wheel feed. Roller presser. For leather. If you are having trouble finding much information online about the machine, just think about how much harder it would be to find parts for.
Most early Singer domestic sewing machines will sew a variety of fabrics from light to heavy (denim or wool coating) with the right needles and thread.