One of the industrial sewing machines needed that you cannot get around in the construction of jeans is the serger or overlock machine. This machine can be used with either 3 or 4 threads. It trims the raw fabric edges while finishing it with an overlock stitch to prevent fraying.
We use both the 4-thread and 6-thread machines for speed. However, you can use either machine for all the sewing purposes if you have only one of the two types of machines. If working with one machine, you could spend more time fudging the differences. Either removing the needle for the chained straight stitch (on the 6-thread) or using a single-needle or chain stitch machine to replace the chained straight stitch in a second pass if working with the 3-4 thread overlock.
We use the 4-thread machine to overlock the edges of the front pocket panels, fly panels, and front rise seams. If the denim does not have a selvedge edge, we also use it at the outseams of the leg panels.
Words: Maurice Malone | March 25, 2020