I recently bough Cobra Class 4. Seller convinced me that it is a perfect machine for leather work. I mostly I need to sew leather patches on the hats. Today is the first time I am running the machine stitch samples. However, there is an issue with the tension and I see bobbin thread pull up and the piece of swatch has waves . Is the issue related to bobbin thread tension. Machine came pre adjusted tension for 1 inch thick leather. I am going to sew on 4mm thickness. Is this going to be an issue?
Thanks your feedback
