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What is an Overlocker – Aka, Serger?

overlocker sewing machine example

First, let’s clear one thing up. The name Overlocker and Serger can be used interchangeably – they mean the same thing, pretty much. It’s the name given to a sewing machine that performs an “overlock” stitch.

Americans typically refer to these types of sewing machines as sergers, whereas here in the UK – and almost everyone else – calls them overlockers. An overlocking stitch, which a serger machine uses, is more closely related to knitting than sewing.

Originally, “overlockers” were mainly employed in industrial sewing situations. But, technological advancements have enabled the development of lighter and smaller machines that can be used at home while producing the same stitch quality as their industrial counterparts.

How do Overlockers Work?

The overlocker sewing machine is unique in that it cuts away the excess seam with a knife or blade, and then wraps multiple threads (which can be 2, 3, 4, or 5) over the raw edge of the fabric to make a clean edge, creating a neat and professional finish.

They are superior machines suited to overcasting and will do this much faster and cleaner than any conventional sewing machine. 

Overcasting is the process of “stopping the ravelling of the fabric’s weave.”

When snipped with scissors, the warp and weft threads can become untethered and often unravel from one another. Remember that fabric is made up of warp threads (threads) and weft threads (also called picks). To prevent material fraying, overcasting is performed, which can be done manually or with a particular sewing machine – in this case, a serger.

Overlock machines are typically equipped with two parallel needles and two loopers. These loopers loop threads around edges, ensuring neat finishing.

In other words, the overlocker (serger) machine will “fix” the edges by slightly overlapping them and then closing them well with a firm yet flexible stitch.

Stitches for Overlockers

A serger may create a variety of stitches. Here are some of the most common stitches:

The overlock stitch with four threads

This lets you sew while overcasting the edges. The machine employs four threads from huge spools (called cones). It’s a stitch that’s commonly seen on stretch textiles like tops.

The three- or two-thread overlock stitch

We utilise this form of stitch to elegantly overcast the edges without attaching two pieces together.  It is suited for fine materials, such as cotton. It can be done with two or three threads, depending on the rendering desired by the designer or seamstress!

The Rolled Hem (3 or 2 threads)

It is also known as a “finishing hem” and is frequently encountered in online sewing classes. It helps you to put a nice finish on the fabric’s edges by rolling them and encircling them with a satin stitch. As a result, the seamstress can “lose” as little fabric as feasible.

Depending on the desired finish, the rolled hem can be done with 3 or 2 threads: with 3 threads, the finish will be different on the front and back of the fabric; with 2 threads, the finish will be the same. Furthermore, the classic hem 3 folded threads is a professional-grade hem.

You can use the 3-thread overlock stitch to trim edges and make seams that are not susceptible to a lot of stress, such as side seams. Thread the thread through one of the needles and one of the loopers. Thread it into the right needle for narrow stitches and the left needle for wide stitches.

The flatlock

As the name suggests, this is a flat seam. To avoid cutting the fabric, disable or remove the overlockers knife as far away as possible. The flatlock lets you stitch two fabrics together or create a beautiful seam (armholes, ruffle of a little dress, scarf, bodice, etc.)

The overlocker is the sewing machine of choice for stitching stretchy (elastic) fabrics such as jersey, fleece, or lycra, according to any self-respecting seamstress and good sewing books.

The serger also offers a perfect hem finish, which is especially important with expensive fabrics. If you enjoy sewing your own garments, this is an excellent machine to own!

Tension of Overlock Thread

Each overlock stitch requires varied tension to ensure that the seam is not broken and is strong enough. The thread tension on simple overlock sewing machines must be adjusted by hand. Many more modern models, however, now include an automated thread tensioner.

Because thread tension is, of course, critical to sewing success, this automation can make your life easier.

Overlocks with automatic thread tension are typically more expensive. Again, you must determine whether you are willing to pay a bit extra. With a little practice, the manual setup is not too difficult, and there is a lot of help available from the manufacturers or on YouTube.

Some materials are extremely tough to deal with on a traditional sewing machine.

Jersey or stretch knits, for example, or veils and other very fine textiles that fray a lot. Cotton can be worked on a regular machine or by hand with thread and a needle.

The serger’s key advantage is that it can sew flexible materials with ease.

Is an overlocker the same as a regular sewing machine?

Are you accustomed to using a sewing machine? The overlock machine is not like a sewing machine, though, and will require some adjustment on your part. Even while both machines operate smoothly because of the pedal mechanism, they are both lovely and highly different, particularly in their design.

The distinctions between the overlock machine, designed for finishing, and the sewing machine, designed for seams, are most obvious at the level of the flatlock, which is outfitted with a multitude of fabric feed dogs for the sewing machine, while the serger has two sets of teeth.

One of the primary differences between the two machines is that the serger allows you to cut the fabric before serging it.

Furthermore, the overlocker includes multiple spots for the needles.  This feature allows you to use multiple threads of different colours while also adjusting the tension of the threads for each needle. The sewing machine does not allow you to change the number of needles.

As a result, the two machines are significantly different. And, while some novice sewers may find it difficult to tell the difference at first glance, it is certain that the two devices do not serve the same purpose, but instead, complement each other.