Enter the Coverstitch

The tricky thing about sewing knitwear is that the (most of) the stitches on a standard sewing machine won’t stretch enough to keep up with knit fabric. 

So the best way to seam knits is with a machine called a serger. If you look at the side seams of nearly any t-shirt, you’ll see what a serger seam looks like.

Serged seam being held in a hand, both sides of the looper-finished seam is showing because the fabric is folded back.

I bought a serger many years ago as one of my plans to “learn sewing for real this time.” (I’ve tried to “learn sewing” ever since I was in my teens. I make a concerted effort every decade or so, to little success.) These days, I mostly use my serger to finish off the raw edges of handwoven fabric before washing it.

I plan to use my serger for underwear construction

However, there are very few seams in underwear. What there are are a lot of hems. The waist and leg holes are essentially three long hems.

There are ways to make a standard sewing machine make a stretchy stitch: use a zig-zag or serpentine stitch or a twin needle and (depending on the stretch of your fabric) you might get stitches that won’t bind or break.

For a truly stretchy hem, however, the tool to have is a coverstitch machine. Turn up the hem of your t-shirt, you’ll a coverstitch hem.

Coverstitch tshirt hem held in a hand with both the double stitch and looper sides showing because the fabric is folded back.

I’d recently sold a loom, and putting the proceeds towards a coverstitch, trading one machine for another, seemed a worthwhile thing to do.

The first coverstitch machine I was interested in was a Babylock Coverstitch. Unfortunately, they’d just discontinued that model and none of the local stores had any left. Not wanting to risk learning on a used machine (how would I know if problems were me or the machine?) I asked what the new model from Babylock was.

“It’ll sew through anything,” the sewing machine saleswoman told me over the phone. “It’s all-metal construction.”

“It’s the size of a small car,” I said, looking at the Babylock website, and then at my modestly-sized sewing table.

“It sews like a dream, you’ll never regret it. And it’s on sale… ”

It was the pandemic, so I bought it without trying it out beforehand. (Something I do not, in general, recommend.)

What I came home with was the Babylock Euphoria. It is huge, it does only one thing, and it does it very, very well.


Only…now I had to learn how to use a coverstitch machine! 

YouTube came to the rescue: GingerHead and Co. and The Last Stitch have some great coverstitch videos. Johanna Lundström from The Last Stitch has a book, Master the Coverstitch Machine, that I am strongly considering buying. I’ve already found at least one of her offhand tips to have made the difference between fail and success with wooly-nylon thread.

And yet, I was intimidated. I didn’t know what tension to set the needles or loopers at, what stitch length to use, or how it sewed… or anything. 

However, I’d just given a seminar on using the scientific method for fiber arts. So I decided to follow my own advice and start by sampling, sampling, sampling. 

I created ‘research samples’, with no intention of creating anything other than information I could use as a reference later. That way, regardless of the result, it would be a success, because I’d learn something.

Pile of eleven samples of coverstitching attaching fold-over elastic to rayon-lycra fabric. The samples are labeled as to what the machine settings were: SL for stitch length, UT for upper tension, LT for lower tension, and DF for differential feed.

In experimentation, it’s good to change as few variables as possible at one time, so I established some guidelines: 

  • 95% rayon, 5% lycra fabric at 6oz weight
  • Fold-over elastic
  • Wooly-nylon thread in the looper

Note: The fabric I used for sampling is from a chopped up shirt, which is why you see other seams on the samples.

I chose the rayon/lycra because it’s soft next to the skin and is one of the standard fabrics carried by Knitorious, a fabric printing collective that takes pre-orders for fun geeky fabrics, has them printed, and then sends them out to folks.

Fold-over elastic is one of the easiest way to finish off hems on underwear. I decided to start with this because (a) I had a ton of it, bought from a local fabric store that went out of business and (b) easy is good.

Wooly-nylon thread in the loopers is often used in underwear and swimwear because it’s a fibrous thread that “fluffs out” after it’s stitched and is known for being next-to-skin soft. I like soft, so it seemed a good thing to do.

Because beige is not a color I typically wear, I used up my beige fold-over elastic when I started my experimenting. Then I had the fun discovery that I could write on the light-colored fold-over elastic with a Sharpie pen, making the samples self-referencing. Yay!

Close up of a sample that is folded so you can see both sides of the chainstitch. One side looks like regular stitches, the other side like a series of crocheted-together loops.

The first few samples I tried were scratchy, something I definitely did not want in the seams of my underwear. 

I experimented (changing one machine setting at a time) until I came up with the idea of using a chain stitch (a single-needle-and-looper stitch that looks like a regular straight stitch on one side and a series of knit loops on the other.) Since fold-over elastic does not have raw edges, this should work fine!

The settings that seemed least scratchy were: SL 1.0, UT 0, LT 3, DF N

SL stands for stitch length, UT for upper (needle) tension, LT for lower (looper) tension, and DF for differential feed (and N means neutral).

It produced a chain stitch which still had a bit of a scratchy rib on one side. If I put that ridge on the outside of the underwear: problem solved!

Turns out that was not the best stitch to use, as I discovered several pairs of underwear later…

4 thoughts on “Enter the Coverstitch

  1. Good job! I needed the “Sample” reminder. That scientific method applies to so many creative endeavors. I think I need to sample brownie making! Seriously, I am enjoying your panty making journey. Thanks for the post and I am looking forward to reading the next one!

    • I am finding, more and more, that my best answer to “but I don’t know where to start…” is sampling. It gets me out of needing the result to be perfect, gets my hands moving, and I end up with valuable information, no matter how things go.

      I am currently discussing with myself whether it’s valid to consider actual projects as “samples” for future projects. That works, right? (I just cut a tiny hole in something I’m sewing as a gift and the repair is…not invisible, so I’m toying with this idea…)

      Also, I very much enjoy having you to share my sewing journey with!

Please share your thoughts: I enjoy your comments and feedback!