Sewing Blog

What Does This Serger Stitch Do?

Craftsy instructor and guest blogger Amy Alan has been getting lots of questions about when different serger stitches should be used, so she came up with this handy guide for us!

For more up-close instruction, check out Amy’s class Beginner Serging: Machine Basics & Techniques, where you’ll learn to make three projects you’ll be proud to show off: an exposed zipper bag, an ombré ruffled apron and a striped scarf!

Sewing blue fabric on a serger

Different serging stitches and how to use them

When you’re learning to use a serger and finding out about all of the different stitches it can do, you might be wondering how to choose the right stitch for your project.

Select a stitch that matches the needs of your project or garment (strength, stretch, edge finishing, etc.). Many crafters use their sergers merely for finishing the raw edges of their sewing projects, but there’s so much more you can use it for when you know how the stitches work.

4-thread overlock

4 thread overlock stitch

The 4-thread overlock is the most commonly used serger stitch. Take a look at the clothes you’re wearing. I’m sure this stitch makes an appearance somewhere! It’s a very durable and strong stitch and your best choice when seaming with your serger.

3-thread overlock

Serger Stitches: 3-thread overlock

A 3-thread overlock is also a nice choice for seaming, but it’s not quite as strong as the 4-thread. This stitch uses only one needle, so you don’t have the extra durability of another needle thread in your seam as you do with the 4-thread overlock. You can still seam with it, but I wouldn’t use it on any area that will have a lot of stress put on it. It’s a fantastic choice for finishing the fabric edge on thick and medium-weight woven and knit fabrics, and you can even make a blind hem with it.

2-thread flatlock

Serger Stitches: 2 thread flatlock

If your machine has the ability to do 2-thread stitches, then you have the option to create an even flatter, thinner and lighter edge finish on your projects. A 2-thread overlock isn’t a good option for seaming, but it will give your project very lovely edges.

This same stitch turns into the 2-thread flatlock, which is wonderful for piecing sportswear fabric and giving your garments the appearance of cover stitching. You should see how stretchy a 2-thread wrapped stitch can be!

Rolled hem

Rolled hem serger stitch

My favorite stitch is a rolled hem. It is beautiful when you use decorative threads and hem sheer fabrics with it. The 2-thread variation of this stitch is perfect when you don’t want to add weight to your garment hem, but a 3-thread rolled hem can appear fuller and more filled in when you use the right threads.

For most of the 3-thread and 2-thread stitches, you have another variable — which needle do you use?

When deciding whether to use the left or right needle, consider the thickness of your thread and also your fabric. The left needle should be used when you’re using thicker thread or sewing on thicker fabric. The right needle should be used when you’re serging on lightweight fabric or using a finer thread.

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Iryna Boehland

Thank you, Amy, for yet another reminder of the versatility of serger’s stitches.


Thanks for this cool article! I’m about to begin the Basic Serger class on Craftsy. Armed with this information I feel like I’m already ahead on getting to know and use my machine.


I loved your Beginner Serger class and I am looking forward to taking more serger classes in the future Could you please add a segment on the cover stitch? I must admit I’m still not comfortable using my serger but I’m building my skills thanks in part to your class. You are an excellent teacher…keep the classes coming!!!


Thankyou! This information is a godsend for me. . There is so much to read in the instructions and with no prior experience with an overlocker, i must say i am a bit overwhelmed.

Faine Roger

Amy thank you so much for the detailed explanation of serger stitches. I did not have a clure about those stitches.


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