How to Serge Corners and Finish Seams

Learning to use a serger can be confusing since it differs from a traditional sewing machine.

A serger or overlocker sewing machine is used to sew seams on garments and home decor.  Most any item needing a finished seam can be sewn on a serger.  The overlock stitch trims, sews and finishes the seam all in one pass through the sewing machine.

This tutorial will demonstrate how to sew inside and outside corners on a serger.  It will also demonstrate how to secure the seams when starting and ending the overlock seams.  These demonstrations apply to any overlocker or serger.

If you need an introduction to the Bernina L450/L460 machine, please click the link to visit our page which lists the features and what is included with purchasing one of these machines.

Learn more about inside and outside corners & securing seams by watching our video or keep reading this post.

WHAT YOU NEED

• Serger or Overlocker machine
• Thread
• Scrap fabric to practice
• Scissors

4-thread and 3-thread Serger Stitches

The two basic serger stitches are the 4-thread and 3-thread overlock stitches. The number of threads used will depend on the type of fabric and seam being sewn.

The 4-thread overlock seam is the seam is used to construct most garments.  It’s also used for areas of high stress such as the crotch seam.  It’s a wide and very sturdy seam that consists of two lines of straight stitching and an overlock stitch to finish the edge.

The 4-thread overlock is the top seam shown in the photo below.

The 3-thread seam is used on light or medium-weight fabrics and for constructing seams on knit fabrics.  It can also be used to overcast and finish raw edges.  This stitch can be made wider by using the left needle or narrow by using the right needle.

If you look inside the seams of most garments purchased at the store, you will find the overlock stitch.  The overlock stitch keeps the seams from fraying while washing or during use.

Thread in My Overlocker

To help show where the threads appear in the overlock stitch, the serger is threaded with colors matching the color coding on the serger. 

• Yellow – left needle
• Green – right needle
• Blue – overlock front loops or upper looper
• Red – overlock back loops or lower looper

Use matching threads on all four spools when stitching with your serger. If you are using a specialty thread, like a stretch thread, this thread may be used on only one spool. 

If you need a tutorial on how to thread an overlocker, follow the link for a full video and photo tutorial.

Securing Seams with an overlocker

Overlockers or Sergers do not have a back stitch function so securing the beginning and end of seams is different from a normal sewing machine.

If a seam is sewn across another seam or edge finish, it is secured.  So, only seams that do not cross over one another need to be secured.

Truthfully, I have sewn clothes with a serger for many years and never really secured seams.  Usually, the beginning & end of seams are sewn over another seam or turned into a hem.  So, a lot of times you can get away with not securing the seams.

I wanted to provide a demonstration though in case you need it!

Securing the Beginning of a Seam

Start with a chain of stitches 3 - 4 inches long.  Usually, your machine will have a chain left over from a previously sewn seam.  If not, run your machine for a few stitches to get a chain.

Take the first stitch into your fabric and stop with the needle down.  The needle down will hold the fabric in place.

Raise the presser foot.  Grab the thread tail around and wrap it around in front of the presser foot and cutter.

Put the presser foot down.  Hold the tail off to the right keeping your fingers away from the cutter.  Start stitching the seam and cut off the thread tail.

Continue stitching your seam.

The photo below shows what the secured beginning seam looks like.

Securing the End of a Seam

At the end of the seam, stitch one stitch off the edge of the fabric.

Raise the presser foot and gently pull the fabric off of the stitch finger.  This is a small tug towards the back of the machine.

Flip the fabric over and around.

Place it under the presser foot just in front of the needle position.  Put the presser foot back down.

Sew back over the previously sewn overlock stitch for approximately 1” and then off the edge. Do not trim the fabric or cut the previous stitching with the cutter.

The photo below shows the secured ending seam.

 

Sewing Corners with an Overlocker (Inside Corners & Outside Corners)

Sewing seams with a serger is quick and easy, but how do you go around corners?  Since the serger is finishing the edges as it sews, the fabric can't just be pivoted as on a normal sewing machine.  

There are several methods for serging corners, but this is my favorite. This method doesn't make loops of thread at the corners or loose threads on the corners.

Both methods described below are very similar except one is trimming the seams from a 5/8" to 1/4" finished seam and the second method does not trim the seam.

Sewing Outside Corners without trimming seams

This first method is used if you want a 1/4" seam allowance.  This method does not trim any fabric off of the seam while sewing.

Start sewing the seam as normal.

Sew towards the first corner.

Sew two stitches off the corner.  The needle will be just past the corner of the fabric.

Lift the presser foot.

To release from stitches from the finger, slightly pull the fabric towards the back of the machine.  Just a very small tug will pull the stitches off the stitch finger. 

Alternatively, the rolled hem selection lever can be pulled forwards, towards the front of the machine (my finger is on the lever in the photo below).  This retracts the stitch finger, releasing the stitches.  Don't forget to push it back into place after turning the fabric.

Carefully turn the fabric 90 degrees and place it under the presser foot just in front of the needle position. Put the presser foot down.  If you pulled the rolled hem selection lever, push it back in place.

Continue stitching to the next corner.

At the end of the seam, secure the seam as described above.  The photo below shows the corners.  As you can see, with this method there isn't a lot of extra thread loop at the corner.

Sewing Outside Corners with Trimming Seams (5/8" Seam Allowance)

Most garments are sewn with a 5/8" seam allowance.  Sewing the outside corners while trimming the fabric is just slightly different than when sewing without trimming.

Before sewing the seam, trim ¼” off of each corner about 1" along the seam. This section of the seam will be behind the cutter so cannot be trimmed by the cutter.  Note that I've trimmed the section after the corner is turned.

Start stitching the seam trimming ¼” off as you are sewing.

Once you get to the corner, stop after sewing two stitches off the end.

Lift the presser foot and release stitches from the stitch finger with a small tug or pull the rolled hem selection lever forwards. 

Turn the fabric 90 degrees and place it back under the presser foot just in front of the needles.  The trimmed edge will be behind the cutter.

The closeup photo below shows the fabric under the presser foot, close to the needles and the cut edge is next to the cutter.

Continue stitching the seam.  The rest of the seam will be trimmed by the cutter. 

 Tack off to finish end of the seam.

Sewing Inside Corners

When you look at a seam with an inside corner, you may think, how do I get around that corner without trimming too much from the seam?  It's actually easier than you would think!

Sewing inside corners can be done while trimming seams or not trimming. If you are trimming the seam as you sew, make a small clip 1/8" into the corner with your scissor before sewing the seam.  This will release the seam enough to open the fabric up and sew the corner.

To sew the inside corner, simply make a straight line from the fabric as shown in the photo below.  If you are trimming a seam allowance, you would make a small clip right in the center.

Start sewing the seam as you normally sew.

As you approach the inside corner, stop and adjust the fabric.  Pull the fabric around so that the seam is a straight line.

Keep sewing and sew across the corner.  Be sure the fabric is feeding well and the corner is caught into the seam.

Finish sewing the seam and tack off if necessary.  That's all there is to getting nice inside corners!

I hope you enjoyed learning about the different overlock stitches, sewing corners, and how to secure seams.

Some other serger tutorials and projects you may be interested in are:

• How to make a Fabric Napkin
• Free Stuffed Bunny Pattern & Tutorial
• Re-usable Unpaper Towels Tutorial

Learn about your serger and seams:

• Introduction to Bernina L450/L460
• Blind Hem with a Serger
• How to thread a serger
• How to sew a Rolled Hem with a Serger