I would also suggest making sure that the threading for both needle and bobbin are correct and going through all guides and springs. Another possibility is the pressure on the presser foot. Do you have a manual for your machine? If not, one can be found at
https://www.manualslib.com/manual/18...ger-15-90.html paying particular attention to pages 13, 17 and 19. (Those are the page numbers for the PDF) That manual has a section on the parts and adjusting the tension assembly. I'm
Janey - Neat people never make the exciting discoveries I do.
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