I started having problems with the bobbin thread and finally decided to take the whole bobbin/shuttle apart and clean it. It was so filthy in there that it required more than cleaning; I had to apologize abjectly and sincerely to my baby. I assumed she’d retaliate for being treated so poorly by going out of time or spitting out the Tiny Screw That’s Impossible To Find If You Drop It, but she went right back together and is stitching beautifully now.