How Does a Sewing Machine Work
Modern sewing machines do the job of a highly skilled tailor in a fraction of the time. Before they were invented in the late-18th century, the fine stitching that we take for granted on our everyday clothes today would have only been available to the wealthiest members of society.
There are several basic methods of stitching that various models employ, but the loop stitch is the most common. This works by passing a needle tied with thread through both pieces of fabric and out the other side, then back again. When stitching manually this involves passing the needle to the other hand and turning it around to go back, which is too elaborate for a machine to perform, and also unnecessary.
Instead a sewing machine uses two parts: a needle and a looping hook. The machine needle passes only partway through the material with the eye at the sharp end rather than the blunt end like its handheld equivalent. As it’s moving through the fabric, the needle drags a loop of thread to the other side, where a hook grabs it and either loops the thread around itself or around a separate piece of thread. The needle then retracts and the thread is drawn tight, fastening the fabric together.
Inside an electric sewing machine is a sophisticated series of gears and shafts that all connect to a single motor. One part of the motor controls a crank that pulls the needle bar up and down, plus a thread-tightening arm, which creates a slack loop and then tightens it to form the stitch. The other vital part of the sewing machine that the motor controls is the feed dog. This is the belt that steadily and evenly moves the fabric forward in synchronization with the needle to create a new stitch. The feed dog is pressed up against the fabric where it rolls forward, shifting the material a short, consistent distance before dropping down again to release it. The entire process of feed dog, needle bar and thread-tightening arm is entirely driven by the motor, which in turn is controlled by a pressure-sensitive footplate operated by the user.
Sewing Machine Facts
Stitch control – Dials and switches dictate the width and length of the stitch. Advanced sewing machines have many more options too.
Electric motor – The beating heart of the sewing machine powers the movement of both the feed dog and the needle.
Presser foot – This forked piece of metal holds the material evenly to the feed dog while the stitch is created.
Fabric – The two layers of fabric are moved forward to receive a new stitch in perfect synchronization with the needle.