There should be plastic over the table your panto sets on.If there is ,just take an eraseable marker and mark the end of your top on the plastic.Then stop stitching at your marks. If there is no plastic,buy a sheet to cover the panto.Without the marking how do you know where to stop stitching.Hence,the needle getting caught on the edge of the quilt.No matter where the bobbin is located,you would have to move the machine off the edge to change the bobbin.