We may have found other answers which could help you.
Click here for Sewing Machine Timing Belt NeedleWhat size needles can I use for my Singer 39a3?
the thread is bunching on underside of fabric it looks like birdnest?
1965 Singer 275k sewing machine foot pedal?
Singer 507?
Need a service manual for a Singer Treadle Sewing Machine Model 66-1?
Bobbin won't wind?