We may have found other answers which could help you.
Click here for Sewing Machine Foot Controhow to get the tension right on my machine?
1965 Singer 275k sewing machine foot pedal?
Presser foot is loose?
My CG 500/550 Singer Sewing Machine's bobbin isn't working?
What size needles can I use for my Singer 39a3?
Singer 507?