Learn all about serged seams. Sergers, also known as overlockers, sew with an all-in-one finish. They sew the seam, trim the seam allowance and neaten the seam with an overlocking stitch all in one motion.
Serged Seams Tutorial
What Can a Serger Do?
The serger can either do an all-in-one process where it sews the seam and neatens at the same time, or you may just want to stitch as normal, and serge afterward to neaten off the seam.
In the photo above, the seam was sewn with a regular sewing machine (green stitching) and then the raw edges finished with the serger (white stitching). Serged seams are particularly useful for knit fabrics as they produce an elastic seam with stitches that will not break.
Types of Serged Seams
In order to neaten your seam with a serger, it is a good idea to know something about the serger’s stitch capacity. Different sergers, according to the number of threads they support, produce a variety of stitching.
Sergers come in different sizes and models. They have different numbers of threads and may do a double line of stitching, or a single, depending on how many needles you thread. A typical number of threads are 3,4 or 5.
- The more threads on the machine, the stronger and wider the sewing will be.
- Even if the machine has up to five threads there is no need to use all the threads. It is possible to sew with the serger and use fewer threads.
The important thing is to ascertain the number of threads that best suit the fabric you plan to sew and to practice on a scrap first.
Advantage of Serged Seams
A serger is not an essential piece of equipment to sew and neaten beautiful seams. However, the advantage of the serger is its ability to finish everything all in one motion. It is a machine that makes your sewing look professional.
An alternative to serged seams is to use a overcast stitches on your regular sewing machine or by hand.
How to Sew Serged Seams Step by Step
Here are the steps to take to complete straightforward serged seams:
Step 1 - Test
The first step is to practice your serger stitch on a scrap of fabric you plan to sew. The loopers and the stitches, and the tension of the serger must be regulated to fit with the fabric.
The serger is going to cut as well as stitch. For this reason, the tension and seam width must be exactly as you would like them to be. If this is your first time, read how to use a serger before you start.
Step 2 - Baste the Seam
Prepare your seam. Sewing with a serger, and knowing your machine is going to cut and trim, means you must avoid using pins where possible. Your machine blade will get damaged if it rides over a pin.
2 alternatives to using pins on a serged seam:
- You can baste the seam by hand first.
- Machine stitch a basting row of straight stitch with your regular sewing machine.
If you are making a pattern you know well or an easy-to-make style you may feel confident to sew freestyle without pinning or basting.
Step 3 - Serging the Seam
Get ready to serge along the seam, and watch how your machine can cut and sew and neaten all in one swoop. You will feel confident in this step if you have prepared and practiced.
Tips for sewing a serged seam:
- When starting, you do not need to lift the foot to place the edge of the fabric under like you do with a regular sewing machine. The fabric will feed forward under the foot.
- Use the stitch guide on the side of the serger machine to ensure you are sewing the seam line at the correct width.
- Make sure you leave a ‘tail chain’ at the beginning and the end of the serging stitch. There is no backstitch on the serger.
Step 4 - Finishing the Serged Seam
The chain can be threaded back on itself using a large eye needle to thread the chain tail and push it back through the stitching. Threading the chain back on itself is essential to the finishing-off process and ensuring there is no seam unraveling.
Alternatively, cut the chain tail with sharp scissors and use fray check on the ends to prevent unraveling.
These four steps form the basics of seam neatening and sewing serged seams. There are some other techniques and variations to consider depending on the garment, the fabric, and the amount of strength required from the seam.
Serged Seams with Corners and Curves
See my article on how to use a serger for extra information and tips on sewing corners and curves for your serged seams.
Other Serged Seams
Here are some other ways to use the serger to neaten and sew serged seams.
Closed Serged Seams
- Sew your seam with your regular sewing machine along the seam allowance.
- Finish the edges together with your serger and press the seam to one side.
This is the basic seam using the serger with the straight sewing threads forming the seam and the looper threads making the overclocking edge. It is your choice as to whether you need three or four, or five threads for your all-in-one closed seam on the serger.
Open Serged Seams
There are two ways you can sew open seams on the serger by altering the order of the steps.
Sewing the Seam First
Stitch the seam with your regular sewing machine along the seam allowance. Finish each raw edge separately with the serger, then press the seam open.
You can also finish the edges first before you sew the seam. Neaten the raw edges and take into account how much of the seam allowance has been trimmed by the serger. You could also choose just to overlock and disconnect the blade of the serger and not have any of the seam allowance trimmed.
When the edges have been serged and trimmed, sew your main seam with less allowance and press the seam open.
A Serged French Seam
It is possible to use the serger to start your French seam and get a really neat edge to tuck into the seam. This is a great way to take advantage of the serger’s ability to overlock and trim.
- Set the serger on a narrow three-thread setting
- Put your fabric wrong sides together and serge the first part of the French seam.
- Press the seam and turn the seam to allow the right sides to meet. The serged part of the seam will be enclosed.
- Use your normal machine to stitch down and complete the French seam. The neatly overlocked edge will be enclosed in the French seam.
Serged Seams - Number of Threads
- Two Thread or Flatlock Stitch - This interesting stitch joins two pieces of fabric together, and the seam, including its neatening, is pulled open to lie flat. The finished seam has a ladder effect on one side with two rows of parallel stitches on one side of the seam and the looper stitches on the other side.
- Three Thread Serged Seams - The three-thread stitch neatens the seams of stretch fabrics. The three-thread serged seam is a narrower seam and not as strong as the serger stitched with four threads.
- Four Thread Serged Seams - The four-thread finishes off a strong seam with a neat finish. It has an extra stitch through the middle of the over-locking threads. This extra stitch is known as a safety or extra-strength stitch.
Serged Seams for Denim and Heavy Duty Fabrics
The serger is a really good way to prevent fraying in denim or other heavy-duty fabrics. Try your serger out on your denim fabric sample using two pieces of denim together to check the fabric is not too thick for your serger.
If your model serger is reluctant to serge two pieces of fabric together, then neaten each side separately. Use the serger to neaten raw edges before starting to sew the seams. In this way, the seam is neatened and fraying prevented before the seam is sewn together.
- Pass the fabric through the serger carefully. Do not be tempted to pull the denim through the serger, as this may cause the fabric to stretch or pull out of shape. It may cause the serger to stitch incorrectly and lose tension causing the threads to tangle or snap.
- After the neatening is complete, sew the seams together with your normal machine and press the edges that have been overlocked open.
The serger is ideal for neatening seams of heavy-duty fabrics that fray easily. The neatened serger edges of heavy-duty fabrics, hidden inside a lining of a jacket, for example, make sure the seam will not fray.
Serged Seams - In Conclusion
The serger makes all the difference in strengthening and completing seams. The ability of this machine to neaten and trim the edges of the serged seams gives the serger the cutting edge over other machines when it comes to neatening and strengthening seams.