Extra Threads in Bobbin Stitch Formation

 I wrote this description of how a sewing machine forms the lockstitch, for a response to someone needing help with extra threads, coming out of their bobbin area, when sewing. It received a lot of positive response, so I want to share it here, as well, so it can help other people fix the "extra threads" mystery.

Complete the stitch before removing your project. Just like hand sewing, the stitch is not completed, until the takeup lever pulls the stitch tight, which is when the takeup lever, and needle, are at their highest point.

Otherwise, those "extra threads", are actually your needle thread, as it encircles the bobbin case, in order to form the loop under the bobbin thread. The upper thread "lassos" the bobbin thread, by throwing a loop around the bobbin case, then the takeup arm playing the cowboy, pulls the loop closed, creating a lockstitch!

By stopping with takeup lever, and needle at highest points, you also help prevent your needle coming unthreaded, when you begin sewing. I still recommend holding your thread ends ("tails"), for the first few stitches, to avoid these issues.

TIP- Needle thread is pulled through the eye of the needle, 12 to 15 times, before being locked in a stitch, so that is a lot of friction on your needle thread. Stitch length actually determines how many times it goes back and forth, with short stitches take more trips back and forth, than long stitches.

Singer included illustrations of stitch formation in their "Machine Sewing Singer" manuals for home economics teachers, to help fix stitching problems, before videos were available.

Threading diagram for early Singer 15