A Comprehensive Guide to Overlockers

A Comprehensive Guide to Overlockers

by Alexandra F | popular guides

There usually comes a point in a sewer's life when they decide they want to buy an overlocker. Perhaps it's because they are fed up with fraying seams, or maybe it's because they use a lot of stretch knits. Either way it can be a tricky decision, because overlockers look pretty menacing and have a reputation for being expensive.

So, is it worth it? Put simply, if you make a lot of unlined garments and want tidier seams, or if you like to use T-shirt style or knit fabrics, then an overlocker can really open new sewing doors for you.

In this guide I will go through everything you need to know to make that decision. I will also compare a few different overlockers, to help you pick the one which is best for you. You can get a peek at my comparison in the table below, but keep reading for more information!

ModelBrother M343D Overlocker
Brother M343D
Brother 3034D Overlocker
Brother 3034D
Janome 9300DX Overlocker
Janome 9300DX
Elna 664 Overlocker
Elna 664
Price Check Price
on Amazon.co.uk
Check Price
on Amazon.co.uk
Check Price
on Amazon.co.uk
Check Price
on Amazon.co.uk
Stitches 3 and 4-thread Overlock
Narrow Overlock/Hem
Rolled Hem
3 and 4-thread Overlock
Narrow Overlock/Hem
Rolled Hem
3 and 4-thread Overlock
Narrow Hem
Rolled Hem
Flatlock
3 and 4-thread Overlock
Narrow Hem
Rolled Hem
Flatlock
Weight 7.2 kg 5.4 kg 8.1 kg 8.2 kg
Accessories Included
(all machines come with a standard foot)
Dust Cover
Brush
Tweezers
Needle Set
Dust Cover
Brush
Tweezers
Needle Set
Gathering Foot
Tweezers
Needles
Screwdrivers
Dust Cover
Screwdrivers
Tweezers
Needles
Brush
Needle Threader
Oil
Pros F.A.S.T Easy-Thread system
Price
Compact & light
F.A.S.T easy-thread system
Quiet
Sturdy
Does flatlocking
Gathering foot included
Elna are a reliable, quality brand
Does flatlocking
Cons This is a budget machine,
so expect some noise
At 5.4kg there’s a danger of
walk-about at high speed
- use a mat if this happens
Can there be a Con with a Janome? For the price, I’d expect an extra foot

How Does an Overlocker Work?

An overlocker (called a serger in the US) does essentially two things. First, it trims your fabric edges as you feed them through the machine. Then, when the overlocker needle hits the fabric, it lays a wrap of thread around the freshly knifed edge, using a knitting action. If you watch an overlocker closely you will see that the action is much more knit than sew.

When you join two pieces of fabric in this way you get a neat, flexible and reliable result, and ultimately a very professional-looking finish. And all at breakneck speed.

Overlocker vs Sewing Machine - What's the Difference?

So, what does an overlocker do that a sewing machine never will?

We've all struggled on with the so-called stretch stitch on our regular sewing machines. But it's a hard-learned fact that these stitches tend to pop and don't allow all that much stretch anyway. Plus, with the two stitches forwards and one stitch backwards thing going on, it´s mind-blowingly slow. There are no two ways about it - for that professional finish, you really need an overlocker. It's no surprise that most of the clothes you own probably had an overlocker used on them!

Let's look at an example. If you look at the vertical centre back seam of this crazy dress you can see it is pucker-free, hole-free and it retains a lot of the original stretch of the fabric. It would be truly horrible to work with this very stretchy fabric on a sewing machine. We all need an overlocker to deal with wonderful fabrics like this.

Perfect Seams on Stretch Fabrics with an Overlocker
Perfect Seams on Stretch Fabrics

How Many Threads?

Overlockers typically use between 2 and 5 different spools of thread to create an overlock stitch. Different stitches use a different number of threads. When choosing an overlocker, I recommend sticking to machines which can do 3 and 4-thread overlocking. I have a 5-thread machine, but I can honestly say that I've never used it for 5 threads. The most I have used is 4.

  • Sewing with 4 threads gives 2 rows of needle “sewing” and 2 looper (wrap around the edge) stitches. This gives a sturdy finish for woven fabrics, as there are two rows of straight stitching running parallel to the seam.
  • 3-thread overlocking consists of a single row of a sparse, occasional straight stitch and then 2 loopers around the edge. The straight stitch in this case does not resemble regular sewing machine straight stitching in the latter case, it has much more flexibility.

For stretch knits I only ever use 3 threads, as it gives a soft stretchy finish. I know we are advised to use 4 threads for a stretch knit (for safety against coming undone in public) but I've never come undone and exposed myself (thankfully) at 3 threads.

3 Thread Overlock on this 4 Way  Super Stretch Fabric
3 Thread Overlock on this Super Stretch Fabric

Overlocker Stitches

In your search for the perfect overlocker, you should also take a look at some of the over stitch option you would like, in addition to the 3 or 4 thread overlock stitch. Here are a few other stitch types to think about:

  • Flatlocking – Flatlocking is a technique which is used to join fabrics edge-to-edge and creates a nice, slim seam which lays flat. I normally use flatlocking for things like joining Harris Tweed patchwork squares or for athletic wear, since it doesn't leave a bulky seam.
  • Narrow Hem – A narrow hem is a 3-thread hem which provides a much slimmer and more discrete edge finish than a standard overlock stitch.
  • Rolled Hem – A rolled hem is another 3-thread hem, but where the edge of the fabric is slightly rolled under before being hemmed. This creates a nice edging effect.
  • Coverstitch – A coverstitch is the wide hem you will find on the bottom of your T-shirt or sweatpants, and it is a really good look for such garments. Although you can buy coverstitch machines separately, some overlocker machines can convert to coverstitch. However I find that a combined overlocker with coverstitch can be a massive headache, and far more trouble than its worth. It takes longer to change the settings, change the bed and drop the knife than it does to actually sew the hem. I think I speak for most dual machine owners when I say that it really is better to have separate overlocker and coverstitch machines than to have to deal with an all-in-one machine. It's a bit like changing a tyre on your car - it looks OK in the films but in reality, it's a horrible experience!

For more information about the different types of stitches, and just general information about overlockers, check out the great Serger Pepper website, and The Stitch Sharer.

Differential Feed

Understanding how differential feed works is crucial to getting good results with your overlocker. Overlockers have two sets of feed dogs, front and back. Differential feed means that the each of the feed dogs can be operated at a different speed. You can adjust the speed of one of the feed dogs using a dial on your machine. It is the dial which is normally set to N - which is normal feed (i.e. both feed dogs move at the same speed).

Differential feed and the ability to adjust the feed dogs in this way allows you to correct the feeding process to account for stretching of your fabric as you sew. But that's not all! You can also use it creatively to obtain different interesting effects, such as gathering/ruffling or the amusingly named lettuce edge!

My Overlocker - The Husqvarna Viking 936

I have a Husqvarna Viking Huskylock 936 computerised machine, and it is quite a beast to look at. It scares quite a lot of my sewing pupils!

My Husqvarna Viking Huskylock 936
My Husqvarna Viking Overlocker!

I bought this machine because I wanted a computerised, combined overlocker and coverstitch machine. In reality though I never use the coverstitch (mainly due to my own laziness!). The stitch quality of this machine is fantastic. Unless I'm stupid and try and go around a tight curve, I never get a skipped stitch, a hole or a pucker. It's beautiful. It is easy to get great results with this machine, as I simply input my fabric type and weight, hit the desired stitch type and the machine tells me how to set the tension dials. I don't need to think. I can also manually alter the stitch lengths if I want to.

The main downside of this machine is that it is truly evil for re-threading if it comes undone. I've actually cried before when it's come undone. It's a really serious matter when you're 3 inches from the finish line, but you now know you've got to wait for your daughter to get home to follow the impossibly teeny tiny re-threading guides.

If something awful were to happen to my Husqvarna Viking I would probably replace it with a Janome. I might choose the 9300DX because although it's not computerised it is good value for money, and it looks easy to thread (I use the word “easy” loosely, because this is overlockers we're talking about after all!). It is also reliable and fast, like the Viking.

Another look at my Husqvarna Viking 936
Another look at my Husqvarna Viking 936!

Overlockers I Recommend

For those new to overlockers, or who don't want to splurge on a computerized machine, I have selected a few popular choices which are very reasonably priced. These are all capable of 3 or 4-thread locking, have differential feed, and will do a good job of tidying your raw edges. A couple of them will do a flatlock stitch so you can join fabrics edge-to-edge.

Brother M343D

Brother M343D Overlocker

The Brother M343D is a budget machine which will definitely get the job done. You can expect some machine rattle, but if you don't need to use it too often this isn't going to bother you. It has 3- and 4- thread overlock stitches, and can do narrow overlock and rolled hem stitches.

The M343D is equipped with Brother's F.A.S.T threading system, and is not too difficult to thread compared to some of the other machines I have worked with. It doesn't come with a scrap catcher, but they are inexpensive anyway.

Brother 3034D

Brother 3034D Overlocker

The Brother 3034D is also quite easy to thread, and has the same stitches as the M343D. It is slightly more expensive than that machine, but has slightly better build quality. It is also very light.

It also comes with a scrap catcher which is a nice addition, and less common then you might think.

Janome 9300DX

Janome 9300DX Overlocker

My top pick out of these four machines has to be the Janome 9300Dx. It is a smooth, relatively quiet machine and working with it will be an absolute pleasure. It also offers a flatlock stitch, which is a good advantage. As you can expect from Janome, the quality of this machine is spot on!

Elna 664

Elna 664 Overlocker

Elna too is a quality brand (you can read more about brand quality on this page). Certainly my Elna lasted me for 20 years and was a dream to work with (like sitting in a Rolls Royce!). It would have lasted even longer if I hadn't force fed it the equivalent of 6 layers of fabric.

The Elna 664 model does 3- and 4-stitch overlocking, also does flatlocking. It comes with an instant rolled hem device.

Essential Tips for Using Your Overlocker

So, we've almost certainly decided to get an overlocker (and maybe one day a coverstitch machine for hemming, but not a combined machine!). The next thing we need to know is how to get the most out of it! Some other resources for overlocker tips include this blog post from Krafty Kat (and the comments), and this DIY Wardrobe post. But I'd like to share with you some of my own important pieces of advice, which aren't necessarily common knowledge. First up...

Tip #1 - Overlockers don't like curves

When you've got a knife leading the way, if you go around a curve the stitching isn't necessarily going to follow in the exact same direction. The result is a tiny but oh-so-annoying hole that you now have no way to repair, because one thing you can't really do with an Overlocker is say to yourself, “Oh I'll just go over that again”. Even if you unpick the horror area, it's now a good centimetre tighter than it was before (as you've just lost your seam allowance to the knife). You can try to straighten out your curved fabric as much as possible with your hands while overlocking it, but still bad things happen to good people! At this point you may just need to instigate a repair with your trusty sewing machine instead.

However, don't worry, I have a solution! We simply change the sewing order to avoid as many curves as possible. When using an overlocker we could never really overlock around a finished fitted armhole, the knife and stitching would never follow such a tight curve (we would definitely end up with armpit poking through). Neither, because of the knife leading the way, can you join up two lengths of stitching without tapering off (in other words, the two ends will never accurately meet).

What we do is sew the open armhole to the open shoulder seam first and then, and only then, sew up along the side seam of the body of the garment and straight up along the under-sleeve seam of the garment. This is easy to deal with if we're following a sewing pattern designed especially for stretch knits, but when we're making something that's been created in our own heads, or we're adapting a pattern designed for a woven fabric, we absolutely must change the order of construction to avoid as many curves as possible.

The other thing to remember is...

Tip #2 - Never let the looper threads come undone

It's not a problem to let the needle threads come undone, as they thread up pretty much the same way as a sewing machine.

If the looper threads come undone though, you're in trouble! They are a nightmare to rethread, even with the colour coding. Always snip off the old colour at the start point of the reel, knot it onto your new thread and then pull that new thread all the way through. If it comes undone and you're either impatient or half blind (like myself) you will need to shout a young, well-sighted and patient person to rescue the situation!

The photo below shows the threading guide on my machine, which I think illustrates quite well how tricky it can be to rethread!

Threading Guide for the Husqvarna Viking 936
Threading Guide for the Husqvarna Viking 936

Tip #3 – Get a scrap catcher

Overlocking can be messy business! Remember to get a scraps catcher to put underneath your machine, or else you'll come away covered in bits. Some people call it a trim trap. You can buy them online, or you can even sew your own.

That's all for now. I would love to read any other overlocking tips you might have in the comments! Happy overlocking!

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One thought on “A Comprehensive Guide to Overlockers

  1. Hello, I’d like to know how I can overlock around a complete 4inch circle, making a disc shape. Is there a machine that can do this?
    Thank you.

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