We may have found other answers which could help you.
Click here for Manual Sewing MachineToyota SL3404D Overlocker leaving big loops?
Sew-tric ltd variable speed motor built 1982 6000rpm r007327?
Singer zigzag 457 Stylist not threading bobbin/making stitch?
Frister & Rossmann cub 7?
How can I mend my Frister & Rossmann sewing machine?
Sewing machine issue?