How To Use A Coverstitch Machine: Cover Stitch Basics

If you’re curious about adding a coverstitch to your sewing room, this post will show you how a cover stitch machine works and how to use one.

Hey y’all, today I’m going to be talking about how to use a coverstitch machine. I’ll explain the difference between a serger or overlocker and a cover stitch. Hopefully that helps you figure out whether you need a cover stitch machine or a serger or both if that’s something you’re considering. I’m also going to be sharing how to knot cover stitching and how to undo it – both things I had to learn when I got my coverstitcher. While this is not generally a machine beginners need, if you’re hooked on sewing and sew a lot of clothing, you might consider saving for one.

What Does A Cover Stitch Machine Do?

A cover stitch is different from a regular sewing machine because instead of a bobbin it has a looper. This means that the stitching is stretchy, even if you use non-stretch thread. This stretch is why you generally see a coverstitched hem on store bought t-shirts – it’s great for knits and gives a professional finish. As you can see in the image above, the two needles on the right side form what looks like a straight stitch, and the looper on the wrong side crosses between the top threads. Some machines can also do a triple thread cover stitch, which looks like the double needle one except there is a third line of straight stitching in the middle of the needle threads on the right side that helps lock the looper threads to make it an extra secure (though slightly less stretchy) stitch.

Some cover stitch machines can also sew a chain stitch, seen in the bottom of the image above. This looks like a straight stitch on the right side and almost like a bunch of crocheted loops made by the looper thread on the wrong side. You might see this type of stitch on the seams of jeans. This kind of chainstitch is very strong as long as it it securely knotted. If it is not finished and knotted securely it pulls out very easily, which makes it a good option for a basting stitch.

Features to look for

The number of needles in a cover stitcher gives you more options. Three needle capable cover stitch machines let you adjust the width of your stitch. I can use two needles side by side for narrow coverstitching or put them in the right and left needle positions for a wider stitch. My machine is a Baby Lock Cover Stitch and I think it does very professional hems on knit fabrics, so I almost always turn to it for that purpose. I also appreciate the jet air threading for the looper.

The Baby Lock Triumph I’ve also used, is a high end machine that sews a little more smoothly, but I prefer a separate serger and coverstitcher. Other features you might like are automatic tension instead of adjustment dials, and differential feed. Differential feed makes the front and back feed dogs run at different speeds so you can control whether fabric is stretching or bunching as it goes under the presser foot. I rarely have to use this on my machine, but I’m glad to have it.

How to use a cover stitch machine to hem

When you sew the hem on a garment using a cover stitch, it’s a little different from a regular sewing machine in that you have to sew from the right side and can’t see the edge of the folded fabric for the hem. So it’s important to measure and press an even hem that you can line up on the cover stitch machine. You want the stitching to stay very close to the raw edges of the fabric. (Note that on the fabric below I was purposely putting the print on the inside of my shirt because I didn’t like it and it didn’t show through to the other side, which was a pretty green I did like).

There are hemming accessories you can attach to many machines that will fold the raw edge for you, but I don’t have one. Make sure if you buy one to check which direction it folds – toward or away from the presser foot. For general hemming you want it to press away from the presser foot surface.

Is a cover stitch machine the same as a serger?

No, although you can get combination serger and cover stitch machines. The Baby Lock Triumph pictured below could convert between a coverstitch machine and an overlocker. But unless your serger says specifically that it will do a cover stitch, it won’t. I know when I was first learning about these machines I thought maybe the description listing a 4 thread overlock meant a cover stitch, but they are not the same. For more on the differences between these machines and why I prefer separate cover stitch and serger for myself, check out this post.

Do you need to use special thread with a cover stitch machine?

No, I use my favorite all purpose thread most of the time. But you can also use wooly nylon, either in the looper thread or in both the looper and the needles for extra stretch. I generally keep my machine with either black or white wooly nylon in the looper and then use matching all purpose threads for the needles, and I find this stretches enough even for stretch fabric used in swimwear.

How to Knot a Coverstitch

As mentioned above, because of the way a cover stitch is formed, it is important to lock and knot your stitches. On a hem you need to tie at both the beginning and end of the stitching. So the image below shows how to do this at the beginning.

1. Find the top threads on the right side. They are black in this example.
2. Using a seam ripper, needle, or pin, carefully pull the top threads onto the wrong side of the hem.
3. You can see the top threads on the wrong side, along with the white looper thread
4. Tie the three (or 2 if you’re doing a chain stitch, 4 if you’re doing a triple needle stitch) threads together in a knot on the wrong side. Trim the threads above the knot.

It’s easier to knot the threads at the end of your stitching. Here’s how:

1. First, make sure you already knotted your beginning threads. Then overlap your stitching by a few stitches.
2. Raise the presser foot, then use closed scissors, a point turner or something similar to sweep from back to front under the presser foot and pull the needle threads toward the front of the machine. Pull gently until you have a few inches of thread, and then cut both threads there.
3. Pull your garment straight back toward the back of the machine. This will cause the threads you just cut to pull to the wrong side of the fabric. Then cut the still attached looper thread and you’re ready to knot all the threads together on the back side of the fabric.

How to Unpick a Coverstitch

If you regularly upcycle clothes, you might need to unpick coverstitched hems to get every last bit of fabric to use. Here’s how to do it the easy way, check out the video below or on YouTube here. Or see the still images below the video for instructions.

1. Use a seam ripper to cut the thread on the straight stitching.
2. Pull the threads to the top side, and carefully unpick enough one stitch at a time until the threads are long enough to grasp and hold.
3. The looper thread should now have a bit to hold on the wrong side.
4. Make sure you know which direction this line of stitching was sewn; this trick only works when you’re pulling in the opposite direction from the way the stitching was sewn. But hold the top threads in one hand and the looper thread in the other, and pull in opposite directions. The stitching should come out fairly easily.