SERGER: THE BASICS
If you are used to using a regular sewing machine, the first time you see an overlocker/serger, it can be quite a daunting experience. You suddenly have two needles, four threads and a large cutting blade. That would be enough to make anyone feel a little overwhelmed. The good news is that you can very quickly learn how to manage this new machine and the results you get make it all worthwhile.
First of all I will clarify that a serger and an overlocker are exactly the same type of machine. They are just referred to by two different names in Europe and worldwide. For the sake of brevity, I will just use the term serger for the rest of this tutorial.
I also have a short video linked at the end of this blog post if you prefer that format.
NEEDLES AND LOOPERS
A serger has two needles, referred to in your manual as the left and right needle. They create a parallel set of straight stitches down the length of your seam. It is possible to remove one or the other of these needles to create a different type of stitch, but we won’t be going into that here, we are keeping things nice and easy to begin with.
Then you have an upper looper and a lower looper. These form a looped stitch around the raw edge of your fabric, and joined with the two needle threads create your serged seam.
Most modern machines use a colour coded system to help with threading. To help illustrate the different threads and how they look on the machine and in the finished seam I have threaded up my machine with the same colours as are used in my threading guide. The left needle can be seen in yellow; the right needle in green; the upper looper can be seen along the top of the serged seam in blue; and the lower looper in red. The lower looper forms a y-shaped stitch and can be seen on the underside of your serged seam. This serged seam forms a naturally stretchy stitch, and that is why it is so popular for home sewists sewing stretchy knit fabrics.
It is very important to thread your machine in the correct manner described in your manual. The looper threads have to interlink with the needle threads in a very specific way to form the correct stitch. It is therefore of the utmost importance to thread your machine in the correct order. Machines can vary their threading order, so do check your manual. If you are using a machine like the Brother 1034D or 3034D which is a very popular serger for the home sewist, you will be able to find videos showing the correct threading online too, so do have a look and see what you can find showing your own machine.
It is also important to thread with the presser foot raised. This opens the tension discs and allows the threads to fully run between them. Not doing this can cause a very messy, loopy looking stitch with no tension. Older machines and those with tension dials that sit on the front of the machines may also require you to drop the tensions on the discs to zero before threading, as sometimes just raising the presser foot will not separate the tension discs. Your manual should give you more information on this.
Using the correct needle is just as important on your serger as it is on your regular sewing machine. I like to use a ballpoint needle for stretch fabrics and a universal needle for wovens. I don’t find the need to use a stretch needle for some fabrics, like swim, on my serger as I do on my sewing machine. Some machines require a certain brand of needle, or a serger specific needle. Others can take generic sewing machine needles. Again, your manual will give you information on this and also show you how to change the needle.
As a general rule your machine will give you guidance as to the tension settings it recommends. My machine recommends tension be set between 3 and 5. Therefore all my tension discs are set to 4. You can make minor adjustments to the tension when dealing with thinner or thicker fabrics but these should only need to be incremental changes of 4 to 4.5 for example. As a rule tensions should not need to be adjusted when using a regular 4-thread overlock stitch very much.
STITCH WIDTH AND LENGTH
If you find you have excess thread at the edge of your serged seam, this is corrected by adjusting stitch width, rather than the tension. Changing the stitch width will move the top cutting blade closer to or further away from the needles. Increasing the stitch width by moving the blade further out from the needles will cut off less fabric and allow the fabric to fill the space made by the serger threads correctly. Your manual will show you your stitch width dial and how to adjust it. Different machines have them located to the left, right, front or even inside the machine.
It is also important to know how to adjust the stitch length. This dial controls the distance between the penetrations of the needles. If you feel you need slightly more stretch to your seam, you can shorten your stitch length to pack more stitches in per inch. This will allow you a little more movement to your seam and give you more stretch.
DIFFERENTIAL FEED AND PRESSER FOOT PRESSURE
The last dial you will want to become familiar with is your differential feed. Unlike your regular sewing machine which only has one set of feed dogs, your serger has two sets. These are the metal teeth underneath your presser foot. Their job is to grab hold of your fabric and pull it through to the back of the machine as you sew. Your serger feed dogs can be adjusted so that they either pull fabric through at the same rate as each other (differential feed set to 1); pull fabric through at different rates so the fabric is stretched out (differential feed set to 0.8); or pull fabric through at different rates so the fabric is pushed together (differential feed set to 2.0). This differential feed can be used to counteract knit/jersey fabric’s natural tendency to be stretched out as it is pulled through the machine, often referred to as ‘lettucing’. Whilst a lettuce edge can look pretty on a ruffly hem, you don’t want the look for your internal seams. Increasing the differential feed closer to 1.5 or 2.0 can help flatten out those seams again.
The use of your presser foot pressure dial can also help with this. Reducing the pressure here will stop the presser foot pressing down too heavily and help to reduce lettucing too. It also allows more clearance for bulkier fabrics. This dial can often look like a large screw on top of the machine, also.
GENERAL TIPS AND MAINTENANCE
In terms of sewing with your serger, it is a good idea to leave long tails of about 2 or 3 inches at the start and end of all your seams, to allow ends to be woven back in and prevent unravelling. A good sharp pair of snips and a blunt ended darning needle or latch hook will be your friend here.
Finally it is worth mentioning that with all the many moving pieces in your serger it can be easy to throw out the timing on the machine. This can be caused by sewing with blunt or bent and damaged needles, or trying to sew through a fabric that is too thick for your machine. If you start seeing skipped stitches or extra loops on the underside of your seam it is a sign that the needles need changing. Sometimes you can also hear your needles start to make a thumping sound as they sew through the fabric. Again this is a sign the needles are blunt and are having to punch, rather than slide through the fabric. It is a lot cheaper to buy a new set of needles than pay to have your timing realigned, so I would advise they are changed regularly. Your manual will also give information about oiling the machine, and many advise oiling before first use. Only specific sewing machine oil should be used and can be bought online or from your local sewing shop.
When removing your fabric from the serger, make sure you are gently guiding the thread chain to the back of the machine. It can be tempting to pull the threads off to the left, but this can bend the needles of your chaining fork and should be avoided.
Make sure you are regularly cleaning your machine. Sergers create lots of offcuts of fabric and thread and your machine can quickly fill with fluff and lint. Using a little paintbrush or a mini vacuum can help you clean all those bits out. If your machine gets too clogged up it can start to impair its function and throw off the timing, so make sure you give it a good clean out after each project.
Take a little time to get used to your new machine and treat it gently and you will soon love it. Sergers can make sewing so quick and easy and give such a fantastic, professional looking finish. It makes sense to learn some of the basics to keep your machine in good working order and give you the best finish to your work.
Prefer to watch a video? The film below shows me guiding you around my own serger, a Bernina L450, known as Bernie.
Hopefully this has given you a little confidence to get to grips with your machine. You’ll soon be best friends!
Dana is a sewing teacher and fabric fancier based in Suffolk UK. She loves making plus size womenswear and funky kids clothes, and you can find her at The Slippy Chicken Company