I found a beautiful Featherweight, but it does not have the model number printed on it. I am sure it is a 221 (definitely not a 222), but I thought it was rare as the rest of the machine does not look like it has ever been used!!?? Any comments/suggestions/explanations as to why this omission on this lovely little machine?

Are you sure it's a vintage Featherweight?? I've seen some that are new and there a lot different from the originals.

you need to go to the Vintage Machine Shop section on the board and ask there....

You would find the serial number on the underneath, nearer the bobbin case end if its a white one. The black ones I think all had the number at the base of the pillar below the Singer badge.

Not all featherweights have a 221 badge on them. Look at the bottom for the number there and look it up. Ruth

The older models of featherweights (before 1956 or so) did not have the model on them. The later ones did. My 1958 model says 221 while my 1950 model just has the badge. Singer made little changes on Featherweights as the years went on. Prior to 1950 they used an scroll design faceplate while later models had a striated (striped) face place and the white ones from the 1960's were just painted white as it cost more to include a metal face plate. Small changes were also made in the feed dog cover plates, position of the light switch and the style of the accessory tray in the case which also changed in later years. All of this makes for interesting reading and if you google Featherweight, lots of facts should pop up.

How can you tell if it is a featherwieght machine?

Featherweights have a very distinct look to them and some very identifiable features. Key features include black suitcase type rectangular box case, machine weighs 11 pounds, flip up extension bed, only sews straight stitch, thin flat bobbins, scroll or striated (striped) face plate and distinctive decals. They do not say Featherweight on the machine and only some models (after 1956) have 221 below the Singer badge. If it comes with the original instruction booklet, model 221 should be on the front cover.

Be aware that alphasew carries a copy of the featherweight that I have heard is not as great quality. I have only seen a few of them around.

Here is a great site for anyone interested in learning more about FW's:
http://www.featherweight221.com/fwrx/index.html