Singer 552 double-thread chain-stitch sewing machine, 1970.
© Science Museum / Science & Society Picture Library
This is an example of a modern high speed industrial sewing machine used for clothing manufacture. It sews at a rate of 7000 stitches per minute. Thus, at an average of 12 stitches to the inch, sewing 10 feet of seam per second is posible. The advantage of using the double chain-stitch in a high-speed industrial machine is that there is no bobbin to be changed as in a lock-stitch machine, yet the stitch remains secure. Thread is taken from 10,000 yard packages, so that it can be used for long periods without the need for replenishment. When in use the machine is mounted on a bench and driven by a motorised pedal-clutch. The preser foot is also pedal operated so that both hands are free for guiding the cloth.