I have been told to AVOID any Singer machine made after 1970. The featherweight is an old classic, and exempt from this condemnation. (They stopped making them in 1964). It was introduced at the 1933 Chicago world fair and produced through 1964. It is cast aluminum, and weighs just over 11 pounds. In the case with all accessories, it weighs just under 25 pounds. It is a straight stitch machine, needs oil now and then and occasionally a replacement belt.
Two books have been written about it. First is Nancy Johnson-Srebro's "Featherweight 221, the perfect portable" (Available new from Amazon.com for $21.55). The other is "The Featherweight and I" by David McCallum (of Featherweight Rx).
The machines sell (on Ebay) for $150 to $300 and up, but rare machines can bring a higher price. Price depends on how well it runs and how good it looks. Be sure the bobbin case is not missing. Most pre-WWII machines have "Egyptian Scrollwork", most post war machines have a stripe pattern (like mine).
Unlike many machines, the needle is installed with the flat side towards the left.
When I got my machine, it was completely locked up, with thread jammed in the loop guard (behind the bobbin). To fix it, I had to remove the hook assembly, clamp it in a vise, and use pliers to carefully but forcefully rotate the bobbin case and get the thread out that was stuck behind it. The clearances between the hook assembly and bobbin case are very tight and a bit of thread in there jams everything up tight.
Read the description of how to work on this part of the machine at T and T repair. This fellow
I have a copy of his instructions here in case his site vanishes someday, as they so often do.
Here is the owners manual:
Some kind soul has placed the service manual for the 221 online:
Tom's home page / tom@mmto.org