Has anyone ever sewn with cordura nylon 1000 denier? It’s heavyweight backpack material. No matter what I do, I can’t get the bobbin thread to look decent, especially when I’m sewing velcro onto it. I’ve tried every machine in my arsenal, including a commercial walking foot, with various tension adjustments on both lower and upper threads. The best looking stitch, believe it or not, comes off of my 1920’s singer. The best way to describe the look of the bobbin stitch is wavy. The top stitches are always perfect, but the bottom looks crowded. I’m using a big needle; tried 16, 18 and on the commercial machine, 20. The thread is nylon upholstery thread. What am i doing wrong?
Thanks in advance,