chainstitch การใช้

Like lockstitch and chainstitch, coverstitch can be formed anywhere on the material being sewn.
The chainstitch is still used today in clothing manufacture, though due to its major drawback it is generally paired with an overlock stitch along the same seam.
:: I managed a large clothing factory for many years and can explain in intricate and fascinating detail how a sewing machine works, whether lockstitch ( the kind the OP has ) or chainstitch-which are the 2 commonest types, but it would take too long.