Am making a purse that involves tubes made with long strips of fabric folded around batting and stitched down. The next step is to join the tubes together, two by two. I cannot seem to get either of my machines to do this. I need a wide zigzag stitch, can use a 5.0 on my Bernina, up to 9 on my Pfaff. on both machines, with a 5 zig zag on the Bernina and a 6.5 on the Pfaff, I have tried using a walking foot, regular foot, greater foot pressure, less foot pressure, different size needles....everything I can think of, but keep getting skipped stitches, sometimes big patches of zigzag then a big patch of straight stitch followed by more zigzag. Both machines do fine on even 4 layers of fabric, no batting, or a regular batting sandwich, so I don't think it is a service issue. Can anyone suggest a solution? Thanks in advance!