Working of a sewing machine
I spent a long time thinking about how best to illustrate the inner mechanisms of a sewing machine and looking at quite a few artworks other people have struggled to draw. So many moving parts are packed into such a small space that it can be difficult to figure out which bit is doing what. The more accurate the drawing, often the harder it is to understand, and I think it’s actually clearer to look at the key mechanisms separately.
A handmade stitch is made by passing a needle all the way through the fabric, pulling a single thread in its wake. The needle is the key element.
But with a sewing machine, the needle’s only purpose is to prick the fabric to push one thread through, so it can make a knot with a second thread before being pulled back up. The knot has become the core.
Here’s a slow motion gif animation of how a sewing machine works:
- The needle tied to the spool thread (or upper thread) pierces both the fabric and the needle plate below it.
- Unlike handheld needles, the eye (= hole) of sewing machine needles is on the pointy end which allows it to push the thread through the fabric without going through itself.
- The needle then rises a little so that the thread, pushed against the underside of the needle plate, folds into a loop.
- The loop is caught by a rotating hook (the bobbin case) which widens it and makes it circle the case and the small bobbin within. This bobbin supplies the second thread (also called lower thread).
- When the hook’s rotation is complete, the lower thread is caught in the upper thread’s loop and together they make a knot.
- Finally, the needle pulls the upper thread back up, tightening the knot against the fabric. The stitch is done and the cycle can start again.
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