While you wait for answers, we may have found some information which could help you.
Click here for Bobbin Frister RossmanThe thread loops under the fa?
Sew-tric ltd variable speed motor built 1982 6000rpm r007327?
How do fill a bobber?
Singer zigzag 457 Stylist not threading bobbin/making stitch?
Sewing machine starts on its own?
Stuck Feed dog?