Showing how to get started in free motion quilting on a vintage Singer class 15 treadle sewing machine. This machine is a 15K dating from 1945. IMPORTANT - DO NOT TRY THIS ON A LONG BOBBIN SEWING MACHINE - YOU WILL BREAK THE NEEDLE. The stitch formation is different on a long bobbin machine, and pulling the fabric sideways or backwards pulls the needle out of the vertical position and will bend it enough to make it come down onto the foot and break.
FREE MOTION QUILTING IS POSSIBLE ON A SINGER 15 TREADLE BECAUSE IT HAS THE CENTRAL BOBBIN MECHANISM. The bobbin is held in a removable bobbin case directly below the needle. This is shown on the video "How to Thread a Singer 15K"