Lockstitch

The term "single needle stitching", often found on dress shirt labels, refers to lockstitch.

Lockstitch is named because the two threads, upper and lower, "lock" (entwine) together in the hole in the fabric which they pass through.

The upper thread runs from a spool kept on a spindle on top of or next to the machine, through a tension mechanism, through the take-up arm, and finally through the hole in the needle.

Then the take-up arm pulls the excess upper thread (from the bobbin area) back to the top, forming the lockstitch.

Some modern household machines offer a slot for user-replaceable custom stitch cams.

It is created in the same manner, except that the needle zigs to the side and then zags back only once every fourth or fifth stitch.

[1] By adding controlled motion of the material being sewn through an additional set of motors, arbitrary customized patterns of 100 cm or more in each direction can be sewn, opening the door to the very popular category of programmable household embroidery machines.

Originally made by Singer in the US and Europe for supplying the demand for heavy-duty clothing for the troops, for many years after the war[which?]