Moreover, many of these machines come equipped with features like adjustable presser foot pressure and feed dogs that improve fabric handling and prevent puckering. Such features make it easier to work with different materials and enhance the overall stitching quality.
Heavy duty machines typically have higher maximum sewing speeds, around 1500 stitches per minute, versus 1000-1200 stitches per minute for standard machines. Again, this allows them to work through heavy fabrics more efficiently. However, heavy duty machines also tend to sew better at slower speeds, in the 500-800 stitch per minute range, for optimal control through thick seams. So they provide a wider speed range to suit the fabric.