Overlock Sewing Machine: How It Works

What’s the Best Thing About an Overlock Sewing Machine? Professional-Looking Projects It Makes Who hasn’t heard about an overlock sewing machine? This machine is a hero of numerous sewing stories.  Neat edging that will not fray is not so easy to achieve after all!  This article reveals 
    • how an overlock sewing machine works, 
    • overlock sewing machine parts and functions, 
and the most intriguing:
    • what is the difference between a sewing machine and an overlocker?
Keep reading to discover the overlocker mysteries. 

What is an overlock sewing machine?

As you have already noticed—if not within your practice, then in the photo above—an overlock sewing machine looks slightly different from a regular one. It’s because it features slightly diverse functions.  An overlock sewing machine is a specialty machine that creates an overlock stitch using three or more thread sources. Overlocking is more visible than a standard straight seam, so it’s a good idea to pick a thread color that closely matches your fabric—suggests Yesterday’s Thimble. If you’re working with a busy print, try to match the most prominent color. You can also go with a contrasting thread, but sew a sample first in case it doesn’t look as expected.  Do you learn to sew and wonder what differentiates overlockers and sewing machines? Both are used for sewing, but they make different types of stitches.
“They are not the same and can’t replace each other”
Threads Monthly responds to the commonly heard question.  An overlock sewing machine (also known as a serger sewing machine) can 
    • trim, 
    • stitch, and 
    • overcast seams as it sews, 
which makes it perfect for
    • inserting a zipper, and 
    • creating delightful decorations with certain stitches;
(read more on ACES) Achieve decorative effects by using special threads in the loopers. Choose from
    • metallics, silks, and perle cotton, which are great to sew seams or finish garment edges, 
    • fine knitting yarn, buttonhole twist, crochet thread, and even narrow ribbon for special effects; 
Speaking of threads, discover our take on sewing machine thread and read how to thread a sewing machine An overlock sewing machine is synonymous with a serger sewing machine. These terms are interchangeable—”overlocker” and “to overlock” are used mainly in European countries, while “serger/to serge” are common in stateside.  An overlock sewing machine does a great job of
    1. saving us time—a typical overlocker sews faster than a conventional sewing machine; it gets to 1,700 stitches per minute,
    2. giving a professional appearance to constructed items—there is no better option that an overlocker sewing machine to achieve seams similar to those in store-bought clothing; 
So if you’re on your way to conquering the fashion worldyou know what to do! Another easy way to upgrade your DIY garments is by designing and ordering different types of woven labels from Super Label Store Ensure you get familiar with these  on the Super Label Store website, where you can upload your logo or design it from scratch Custom sewing labels An overlocker produces overlock stitches to sew over one or two pieces of cloth. Some of these machines come with built-in blades and trim off excess fabric along the edges to prevent fraying—notes Overlocker Guide. You can use this machine to sew an array of items, from sportswear and draperies to placemats and napkins. With its superb speed, you’ll finish simple items like a T-shirt or jogging outfit in minutes.  Despite all their handy features, overlock sewing machines don’t replace the conventional sewing machine. Yet, an overlocker compliments and enhances your sewing room, making your projects look more professional and last longer. Also, if you’re looking for sewing room ideas, check our review of sewing machine table types.  According to Treasurie, you’ll usually:
    1. sew a seam with your regular sewing machine and 
    2. finish the seams with your serger; 
We’ll get to the differences between both types of machines in the next paragraph! Overlocks form interlocking stitches using  (keep in mind that the price of this device increases with the number of threads and loopers it features; choose the configuration that suits your needs best)
“This specialized machinery is more like crochet or knitting than the stitch of a conventional machine. Loopers replace the traditional bobbin and interlock threads together.
—explains ACES Blades trim seam edges ‌in front of the needle or needles. In some overlock sewing machine models, the upper knife can be rotated to disengage the cutting action. In other models, you need to remove a blade to stop the machine from trimming. Best sewing machine with an overlocker function Image source: Overlocker Guide

Overlocker vs sewing machine

We mentioned that an overlocker and a regular sewing machine are different devices with features that complement each other.  Let’s get more precise and tackle the differences between regular machines and overlockers.  Here’s an engaging video take on “Sewing Machine vs. Serger” by Nadira037 In the meantime, read how to sew and how does a sewing machine work on our blog Let’s have a look at the comparison chart by Threads Monthly:
Regular sewing machine  Overlock sewing machine
Straight stitch Yes No
Zig-zag stitch Yes No
Embroidery stitches Yes No
Create buttonholes Yes No
Insert zippers Yes No
Overlock or mock overlock stitch Yes Yes
Rolled hem Yes Yes
Attach piping Yes Yes
Gather fabric Yes Yes
Blind hemstitch Yes Yes
Mock flatlock stitch No Yes
Cutting knife No Yes
When it comes to the stitching speed, a regular sewing machine typically features 300-800 stitches per minute, while an overlock sewing machine reaches a whopping 1300-1700. A sewing machine uses one thread, and an overlocker uses more than four.  Your regular sewing machine may have a mock overlock stitch. What does it mean for your sewing experience? These machines can do a stitch similar to an overlock (but there’s no cutting knife in the machine). If you aren’t sure whether your sewing machine has a mock overlock stitch, search for these indicators: Overlock sewing machine Image source: Threads Monthly You can do all sorts of tricks, but the truth is there is no sewing machine with an overlocker. A professional sewing room will often have both options to be prepared to handle all kinds of sophisticated projects.   Don’t give up on your sewing machine, either! You still need it for basic sewing needs, cuts, angles, and other techniques that a serger cannot perform. Overlock stitch sewing machine Image source: Mood Fabrics Let’s see what are the differences between a sewing machine and an overlock machine according to Sewing Machine Buffs:
Sewing machine Overlock machine
Speed Depending on sewing machine brands, but typically slower Faster—an average overlock can produce professional work about half the time it would take a sewing machine.


(Not sure what is it? Check our sewing machine parts article)

Shorter Longer
Threads Up to two cones of thread 3-8 cones of threads
Operating method (sewing fabric) Allows sewing your cloth from any side Only allows one side serging (left side)
Operating method (seams) You’ll first have to sew your cloth after cutting it Reduce excess seam and binds fabrics simultaneously
Flexibility More flexible(allow any side sewing) Less flexible
Decorative stitching Can perform decorative stitches Makes some decorative stitching techniques look easier and simpler
What about sewing machine repair? Will you be able to fix your serger at home? Check what there is to know about overlock sewing machine repair, maintenance, setting, and replacement of different parts on Textile Learner. Cheap overlock sewing machine Image source: Wiring Database Info

Can you do an overlock stitch on a sewing machine?

An overlock stitch is a combination of a straight stitch and a zigzag. It sews backward and forwards in a straight line, but between every set of straight stitches, it sews a zigzag—like in serging, a technique used to sew most store-bought clothes. (read more on Yesterday’s Thimble) Can you overlock on a sewing machine? Overlocker Guide mentions that a standard sewing machine features various overlock foot attachments for overcasting fabrics.  The problem arises because a regular machine only uses only two threads at a time.  Overlocker for beginners Image source: We All Sew Therefore, an overlock stitch created with the use of a regular machine 
    1. cannot create the stretchability and durability needed to prevent the edges from fraying, and 
    2. lacks the precision required for seam-finishings; 
To make it perfect, we need overlocking equipment with multiple threaders, stitch locks, stitching loops, and blades. Not to mention that a typical overlocker performs all three overlocking steps in one go. How to use overlock stitch on sewing machine? Let’s glance at the video by oxmanagain where he reveals “Why You Will Never Need A Serger Sewing Machine – Learn Overlocking & Overcasting”:

Overlock stitch sewing machine models

All in all, an overlocker, alias serger, is a special-purpose machine that produces professionally finished seams, using between two and nearly a dozen threads. (read more on Sewing Brighton) We use it to clean-finish the seam allowances and much more.   An overlocker encases the raw edge of the fabric with an overcast stitch while trimming away the seam allowance—operating at pretty fast speeds. Instead of a bobbin and single needle as in regular machines, the overlocker has a cutting blade, “loopers,” and multiple needles.  Luckily, overclockers aren’t those historical, heavy, industrial overlock sewing machine constructions, impossible to use in our home sewing practice. Nowadays, overclocking devices are diverse in their stitch capability, easy to operate, and affordable.  Where to find a cheap overlock sewing machine?  Threads Monthly notes down the following “4 Best Cheap Overlockers for Beginners.”
    • Brother 3034dwt,
    • Brother 2104d,
    • Brother m343d,
    • Elna 664;
We tackled ‌sewing machine for beginners, kids sewing machine, and the best sewing machine options here.  Sewing machine overlock combo Image source: Pinterest There are several “Best Serger Machines for Clean Seams” indicated by Art News:
    • Brother 2340CV Coverstitch Serger,
    • Singer ProFinish 14CG754 Serger,
    • Juki MO654DE Serger,
    • Juki MO-1000 Serger,
    • Janome MyLock 634D Serger,
The top three sergers in the market come as a recommendation from Overlocker Guide:
    1. Juki MO – 734DE Overlocker (higher price),
    2. Janome Cover Pro 2000 CPX (medium price), and
    3. Jaguar Starter 098 Overlocker (low price);
How about a sewing machine overlocker combo? Is there an all-in-one machine that has it all? Having one machine instead of two is a sure way to save your precious space in the sewing room.  Singer Professional 5 14T968DC is said to respond to this need, but is it really that great? Read what’s behind this ingenious invention on Sewing Is Cool. And if you’re still hungry for sewing knowledge, look how we broke down topics of Overlock sewing machine parts and functions Image source: Garage Sale