I am having the same problem with my FW 221 - sewing fine until it doesn't and I find the bobbin thread out of the tension finger in the bobbin case. Yes, these are reproduction bobbins and cases (I'm guessing), but I have used the same bobbins and case for a lot of sewing since I pulled this machine out of storage, cleaned it up and oiled it. Today is the first time I've run into this problem. Any suggestions???