The Kenmore 120- bobbin is designated as 'H'. I have an old package of these and it says that they fit the Singer 221.
I haven't tried them to see if they fit the bobbinwinder pin on the 221, but size-wise then are exactly the same.
I went to my sewing repair man here in Michigan, I did call this morning to make sure he had them. He said of course! So this afternoon I went over and got 5....$.85 each, but I now have them in hand. I asked him what size they were, after looking them up in the catalog....he said "size 20" So that should settle that, right? Anyway, now I can fill these up with different colors.....I am making an Irish chain, and also the Baby quilt I saw on this Board a couple of weeks ago...taking it all to Shipshewana IN on Wednesday.
Joe, I must have gotten the bobbin tins mixed up. I got another one out of my 66 tin and it wouldn't EVEN work in the featherweight. It worked in the Spartan, but not the FW. Sorry for my bad! I'm a dingbat (according to DH), but I can tell a FW from a 99!
If you have a Country Stitches around there, they might sell them. They do here in my town. Take your bobbin with you if you do go there, make sure you get the right thing. As Joe said, not a 66. Takes special bobbin
I have a FW 221 and I found this site on the internet. It is called www.april1930s.com
I ordered bobbins and they were very prompt in shipping them to me. I think they were between $6-8 for 8 or 10 bobbins. Or there is a sewing shop in Flint called All Sew that as FW supplies. I bough my 1/4 in foot there. that's not too far from you and it was easy to get to. I live in Romeo so it isn't too far. Deanna I'll pm you and maybe I can tell you a little about the guild I belong to.