I have had problems with thread breaking at the point when I was in the middle of my quilt. I finally figured out that it was the quilt sandwich getting trapped at the corner of my my Sew Steady table, with so much bulk right at that point when I leaned forward to FMQ I would trap it there with my elbow. It snapped the thread every time. I have trained myself to lift and bunch that area of the quilt every time I need to move my hands. You could check to see if this is happening to you. just a thought.