Ah yes, featherweights are wonderful. Singer did it right at one time, they stopped making them around 1965. When other companies were making zig-zag's, Singer couldn't compete. I have 7 featherweights. All but 2 from e-bay and each in wonderful condition. I love sewing with each and every one of them. One is a centennial, 1951. One is white (they call it celery), it actually has a greenish tint to it and one is a free arm. That's the pricey one as there were fewer made. My others are just regular black machines. Most of the real rare/pricey machines were made for special events, had fewer made so the price is high. Commemoratives like San Francisco - Chicago - and one for Texas are extremely rare so prices are in the thousands. Blacksides and crinkles are other hard to fine machines. No shinny parts or decorative designs on those as chrome was needed for the war. Singer also made a tan featherweight. They weighted 11 pounds, so that's where they got their name from. Small, compact with a fold down bed extension. Fits into a small black carrying case. The first cases had a leather handle, then about the early 40's they had a plastic handle. You won't find any made '42-'44 because they were issued to the army for use during the war and reportedly distroyed after the war.
You can get the actual day they were 'born' (commissioned date on the assembly line) by going to www.singer-featherweight.com. The whole web site is very interesting but Page One will give you an idea for the date. Or call 1-800-4-singer, have your sn# handy and they will give you the date.
I could go on forever about featherweights, some day I'll have a red one. Still looking for one that needs rescuing so I can get it painted. Some people believe that painting lowers the value, but just try to buy one that's been painted and you'll pay twice as much.
Sorry I got carried away, but featherweights are my passion. I got my centennial from Maine, my sister got one from Maryland about the same time and the serial #'s are 310 apart, commissioned on the same day. We have twins!!