Lockstitch

A lockstitch is the mechanical stitch most commonly made by a sewing machine.

Description

The lockstitch uses two threads, an upper and a lower. The upper thread runs from a spool kept on a spindle on top of or next to the machine, through a tension mechanism and a take-up arm, and finally through the hole in the needle. The lower thread is wound onto a bobbin, which is inserted into a case in the lower section of the machine. To make one stitch, the machine lowers the threaded needle through the cloth into the bobbin area, where a hook catches the upper thread at the point just after it goes through the needle. The hook mechanism carries the upper thread entirely around the bobbin case, so that it has made one wrap of the bobbin thread. Then the take-up arm pulls the excess upper thread (in the bobbin area) back to the top of the machine, the tension mechanism prevents the thread from being pulled from the spool side, the needle is pulled out of the cloth, and the feed dogs pull the cloth back one stitch length.

Lockstitch is so named because the two threads, upper and lower, "lock" together in the hole in the fabric which they pass through. The term "single needle stitching", often found on dress shirt labels, refers to lockstitch, as opposed to chain stitch which unravels easily and is usually used on lower quality garments.

Prevalence

Most home sewing machines are lockstitch machines, although sergers have entered the home market in the past ten years or so. Of a typical garment factory's sewing machines, half might be lockstitch machines and the other half divided between overlock machines, chain stitch machines, and various other specialized machines.

ee also

* Overlock
* Chain stitch
* Sewing
* Sewing machine