Thread bunching on bottom! Only doing it when sewing heavy nylon webbing. Doesn't matter the thread or bobbin or needle (already switched out). Sews fabric fine. Was working fine days ago on
AHH Brand Super Heavy Duty Nylon Sewing Thread
Sewing a Box X Stitch in Webbing & Breaking Strength Formula - YouTube
Nylon Fabric: How To Sew Ripstop - Tips, Tricks & Projects | Canvas ETC.
Sewing Tactical Nylon Webbing with a Consew 206RB Industrial Walking Foot Sewing Machine - YouTube
Sewing Technique: sewing nylon webbing with a box stitch onto the face of a duffel bag. There are different ways to accomplish this step, this is one we've found to be useful