I can almost guarantee that the problem is a bit of thread caught in the bobbin area. Just because you don't see it easily doesn't mean it's not there. David McCallum's book will give you detailed instructions on how to fix the problem. Tip: get a strong magnetic dish at the auto supply store to hold those tiny screws, and magnetize your screwdriver while you're at it. Also, make sure you have no distractions (kids, pets, etc) when you are removing that tiny gib screw. Dropping it will cause you to increase your vocabulary..............!

Oh, goody, a project for next week! I've got to get one of those magnetic bowls to have around...Harbor Freight is nearby so I'll head off to there on Monday! I was embroidering on felt yesterday and my thread kept shredding. Haven't had that in a long time. I took off the needleplate, took out the bobbin and bobbin case and cleaned it out with a good brush. I couldn't see a snippet of anything in there but once I put it all back together...no more problems. I think it was Santa's Elves being naughty!!

If you can't figure out what is causing the problem, you can join the Yahoo Vintage Singers Group and get a lot of info there. Usually, you will be able to fix problems with vintage machines yourself, at least that has always been my experience. You've been given a lot of advice here and hope you get it fixed. Love those little featherweights!

I have his book and it's worth it's weight in gold...lol! The first chapter of Part 1 is called..."There Are Birds Nests Under the Throat Plate, Crunch, Crunch, Crunch" :D :D