Four Favorite Seam Finishes for Sweater Knits

There's more than one? I don't need a serger? These are some of the reactions I sometimes get when I bring up the topic of seam finishes for cut and sewn sweater knits. Regular readers of this blog and students of my How to Cut and Sew a Sweater course know that you don't always need an overlocker or serger. In fact, though it's quick and neat, an overlocked seam may not be the best finish for your project.

I don't believe that any one finish is right for everything. Here are my four favorite seam finishes in random order. The best one is the one that works with your project, your time, and your style.  None of these methods could work in the garment industry, but they're perfect for sewn sweaters in your handmade wardrobe. Remember each finish must be tested on scrap fabric to get machine settings just right.

1. The Stretchy Hong Kong Finish

I've done tutorials for this one. The bound seams are neater than the typical overlocked seam and look fabulous on the inside of a cardigan. This seam is created with a home sewing machine.

Choosing the right binding material is crucial. The binding fabric, cut into strips, is what encloses the seam allowance. It must be lightweight and stretchy. I've used both flyweight cotton rib and a very lightweight linen jersey for this purpose. Both of these fabrics can be somewhat difficult to find and come in a limited range of colors.

Stretch mesh is easier to find and is available in a wide range of colors. It also has great recovery, which will keep your seams from stretching out or becoming wavy. One drawback is that synthetic nylon mesh may not work aesthetically with your natural sweater fiber. But as with any of these finishes, you get to decide what the inside of your sweater looks like.

The Stretchy Hong Kong Finish works well on a cardigan where the insides sometimes show. It takes three passes under the machine to sew this beauty. It's not the finish to use if you're in a hurry.

2. Overlock with Stretchy Nylon in the Loopers

I first wrote of this technique awhile back and used it again in a recent project. I had been using Maxi-Lock Stretch textured nylon in the loopers of my serger, which I really like. It plays nicely with my serger, and the thread seems to expand a little in width once it's sewn. It provides a nice coverage on the seam allowance.

Using it is not very different than using serger thread in the loopers. Machine settings are the same. If you find the look of an overlocked seam allowance acceptable, you’ll be even happier with a seam allowance finished with textured nylon.

I happen to love when the thread color matches the fabric. But let’s be real: Maxi-Lock Stretch textured nylon thread has only 36 shades, which are not enough.  I was less than happy with the color selection when I decided to sew a cardigan in rich dark chocolate Washington Square fabric. I couldn't find a matching color, and there were no contrasting colors that worked for me. I returned to a technique that I hadn't used in years….

3. Overlock with Yarn in the Loopers

This method will only work if you have access to matching yarn, of course. Machine knitters, this technique is for you!

I've now experimented with this overlock technique with yarn in the upper looper (pictured above), yarn in the lower looper, and yarn in both. Adjusting the looper tension on the serger is key to a successful finish. The best tension is sometimes tricky to adjust and may depend on the texture of the yarn.

I like the look of all three possibilities of looper yarn threading. After washing, the looper yarn (I've only tried this with wool) really seems to blend in even more with the seam allowance.

For people who sew sweater knits purchased from a shop, using method 2 with stretchy nylon is a great alternative. Tension adjustment is easier too.

Both of these overlocking methods can be combined with the next finish.

4. Catch Stitch to Hold Down the Seam Allowance

Used with a hem in this example, a catch stitch for a seam allowance must be combined with overlocking either with regular serging thread or specialty thread or yarn. I believe it could even add a little panache if zigzag-and-trim is your seam finish of choice.

A catch stitch does take time. Whether it's executed with thread, textured nylon, or yarn, the stitch will keep the seam allowance close to the sweater, thereby flattening and neatening a seam allowance that's inadvertently wavy.

When the catch stitch is sewn with thread, it can be worked as a blind catch stitch, sewn between the seam allowance and the sweater so the stitches don't show. My preference is to sew the catch stitch, so it is visible. A neatly sewn catch stitch with the right contrasting color can make a special and secret design detail.
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These methods are my favorite finishing touches you can use on your self-sewn sweater. I'd love to know which ones you've tried.

If you'd like more tips about creating well-executed seams on sweater knits, especially when dealing with wavy seams, check out my Roadmap for Improved Sweater Knit Seams. Happy seaming!

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