If you are referring to an overlock sewing machine, it will cut
the edges of the cloth as they are fed through. Also known as a
serger.
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An overlock machine is designed to do this job. However you can
do overlock by using the zig zag stitch. When sewing edge of
garment bring stitching right to the end to create an overlock
stitch.
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With a seam ripper and lots of patience. Remember, an overlock
(or serger) machine uses up to 4 threads at one time.
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One can purchase an overlock sewing machine from a number of
physical and online sources. Companies like Amazon and eBay sell
these types of products for example.
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A good overlock sewing machine could be purchased on websites,
or straight from popular retailers. Amazon, eBay, or Craigslist are
good places to start looking if you want a good deal!