Question: what are the three major parts of a lockstitch sewing machine?
Answer: Spool pin: The main function of spool pin is to hold the spool of thread., Bobbin binder spindle: During winding, bobbin is placed here., Bobbin winder stopper: ... , Stitch width dial: ... , Pattern selector dial: ... , Hand wheel: ... , Stitch length dial: ... , Reverse stitch lever: