My Singer is about 15 years old. I have tried all kinds of Singer bobbins and could not find one that would work. I can tell because only the correct bobbin works on the bobbin winder. After reading this board for a while, I learned there are different Singer bobbins. My manual did not tell me. I had to go to the tech info for my model on the Singer web site to find that I needed a 15J. They are hard to find. I finally found some at a sewing machine parts site. And they only come in plastic.
Find out the correct bobbin for your machine. I saves a lot of problems. It is not true that a bobbin is a bobbin is a bobbin.