My sewing machine was making noise and the bobbin thread was coming to the top. I got the book out and played for a weeks with all the tensions. Nothing. Stopped into the sewing store for advise. They suggested I needed a new bobbin case. So I reluntley bought a new one $40.00. Well lo and behold my machine is quiet and smooth and like brand new. The sewing store just looked at my old bobbin case and said Oh My.