Thank you for the link! I have to really clean out the lint with every bobbin-winding. I've got two machines -- a new one (electric buttons and everything) and a 1963 Singer. I'm working on a threading issue with the new one and pulled the old one out of 'retirement' and after some cleaning up, it worked perfectly. I'm going to go through this advice and see if I can't get the new one working right again.