I've always wondered about this, and I'd like to know if anyone has ever tried it. What would happen if you just wound more thread onto the bobbin? I don't think this would work with an older machine, but my machine doesn't require that I even pull the bobbin thread to the top. When I rewind one, I just start sewing and it takes care of itself. So I wondered, would it just pick up the new end when it finished with what I had newly wound on? What do you think? One of these days I'm going to try it; but I thought if someone else already had, you could either encourage or discourage me from doing it.