Seam Finishes

Today, I’ll be covering some basic seam finishes. Tomorrow, gear up for self-finished seams. Friday, I’ll be back with some decorative seams which are going to be really fun and I think you’ll have a ball dreaming up where to put those in your next garment. Let’s jump right in – shall we?

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Machine Zigzag or Straight Stitch

Let’s start with one that most people know and do – Machine Zigzag. After you’ve sewn a seam, you can use a zigzag (or a straight stitch) to finish the edge. Start by zigzagging (or straight stitching) down one side of the seam allowance, 1/8″ from the edge. Next, do the other side. If needed trim your fabric close to the stitched edge. Use a smaller stitch length for lightweight fabrics and a longer stitch length for heavy, bulky fabrics. Easy, peasy.

Use for: lightweight to heavy & bulky fabrics.
Application: apply this seam finish after you’ve stitched a seam allowance and/or before you insert a zipper

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For this next seam finish, you’ll need a pair of pinking shears. I have a Gingher pair and I love them. To use pinking shears you’ll need to first straight stitch down one side of the seam allowance, 1/4″ from the edge. Then trim 1/8″ from the edge with your pinking shears. Voila! Done!

Use for: firmly woven fabrics.
Application: apply this seam finish after you’ve stitched a seam allowance and/or before you insert a zipper

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Hand Overcast

This next seam finish is done in part with your machine and part by hand. You’ll need to straight stitch down one side of your seam allowance 1/4″ away from the edge. Trim away 1/8″ and then overcast the seam by hand just past the machine stitching. The overcast stitch is done by taking diagonal stitches over the edge and spacing them evenly apart.

Use for: lightweight to heavyweight fabrics
Application: apply this seam finish after you’ve stitched a seam allowance and/or before you insert a zipper

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Turned Under Seam Finish

A turned under seam allowance is also a great option and looks really nice on the inside. To do this, simply turn under your seam allowance 1/4″ or smaller and stitch in place 1/8″ from the edge down each side of your seam allowance. If necessary, trim the inside raw edge close to the stitching.

Use for: lightweight to medium weight fabrics
Application: apply this seam finish after you’ve stitched a seam allowance and/or before you insert a zipper

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Serged Seam Finish

For those of you who have a serger, you can easily finish a seam allowance by serging down each side. I also like to finish with my serger before and instead of pressing the seam open. After I serge, I then press the seam to one side.

Use for: lightweight to heavyweight fabrics
Application: apply this seam finish after you’ve stitched a seam allowance and/or before you insert a zipper

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Bound Edge & Hong Kong Finish

Bound Edge finishes are very similar to the Hong Kong finish, except that you use a double fold bias tape to finish it off. To do this seam finish, you can buy or make your own 1/2″ double folded bias tape. Sandwich your seam allowance inside of the double folded bias tape and pin.

Stitch through all layers of fabric (top bias tape, seam allowance, bottom bias tape) 1/8″ in from the edge of the bias tape. And your finished!

The Hong Kong Finish is a really great option for many different types of fabrics, especially jackets that are unlined. For this seam finish, you’ll need 1 1/4″ wide bias strips. With right sides together, stitch the bias strip to one side of your seam allowance with a 1/4″ seam allowance. Trim the bias strip to 1/8″ from the edge.

Press the bias strip over towards the seam allowance edge.

Turn the bias strip to the back of the seam allowance and stitch in the ditch (where the bias tape and the seam allowance fabric meet) from the right side of the seam allowance.

Use for: lightweight to heavyweight and bulky fabrics
Application: apply these seam finishes after you’ve stitched a seam allowance and/or before you insert a zipper

Happy Seam Finishing Everyone!




11 thoughts on “Seam Finishes

  1. Thank you so much for this info! I definitely need to spend more time thinking about seam finishing. I have been pinking thus far but not running a straight stitch inside of it, oops!

    But here’s something that has always perplexed me, and I have never really found and answer for: seam finishes on set-in sleeves. Do you do one of those treatments before setting in the sleeve, along both the curve of the cap and the armhole? It seems like that would be really complicated to orchestrate. I haven’t managed to figure this one out and am not really sure how to approach it with fray-prone or sheer fabrics, and I haven’t found references in my new/vintage sewing books, either. I understand the idea for flat seams but take it to 3D and my head goes boom. I would love it if you’d consider doing a post on seam finishes for sleeves sometime in the future. 🙂

    1. Hi Tasha!

      I think I might approach this next week – sort of a seam finishing in action type thing. I’ll definitely show sleeves as well as various other places too.

  2. This is such a great reference post. I do have a serger and love how easy it makes it to finish seams, but it doesn’t work well on everything. I’m kind of laughing about the first one because I never realized that for a zig-zag seam finish, you’re not supposed to actually let the zig zags go over the edge! It looks so much nicer, and I wish I’d read this before I sewed the zig-zag seam finished shorts I’m just about done with!

    1. Actually, I’ve seen it done both ways, but sometimes the fabric gets all caught up in the feed of the machine. I prefer to trim the seam a little if needed after zigzagging to prevent this as its happened more times than I care to admit. I’m sure your zigzag looks great though – wouldn’t worry too much. Either way, you do have a finished seam!

  3. Thank you so much for this post ! This is so useful and it got me motivated to try some new finishes. Can’t wait for your next post !

  4. Thanks for a great post, this is so helpful! Becky mentions she sews the zig zags going over the edge and I have been doing the same; when I first read your post I thought I must’ve been doing it wrong all this time but I just checked my sewing machine manual and it has a picture of the zig zag going over the edge, and they call it overcasting. The end result is pretty untidy though, an unsatisfactory cross between your first zig zag example, and the serged seam finish. I never thought of sewing the zig zag within the seam (your first pic) but I will give that a go.

    1. My sewing manuals also say the same, but I have to admit that for alot of fabrics, when I’ve done this seam finish, the fabric gets all tangled up in the machine feed. It is a nightmare! I prefer to trim the edge if needed – works just a little bit better without the hassle of having it rip up your fabric.

  5. Hi Sunni,

    May I know when I hand overcast, will it be strong enough for the washing machine?

    I have been using the Hong Kong finish method for a blouse I am currently making. I noticed in your tutorial that the binding that is behind the seam is a raw finish. Won’t it fray? Again will it be okay to machine wash? I use store bought bias but I can only get 1/2″ wide around here unless I cut my own. And stitching in the ditch can be quite finicky 😦 If I cut the binding myself, must it be on the bias?



  6. Hi Barbara!

    So sorry I didn’t see this comment come through until you pointed it out! Here goes! Usually when you use a hand overcast, its on fabrics that aren’t necessarily meant to be washed in the washing machine, so my thought is, no its not meant for those fabrics. Silk and wool fabrics are where I’ve mostly seen it.

    For the Hong Kong finish method, you should be using a bias binding. The reason being is that bias cut things hold up to fray really well. In fact, they shouldn’t and don’t fray if only a tiny bit. If you are cutting the binding yourself, definitely use bias binding because of the frayage factor and because all in all fabrics cut on the bias end up being a little thinner than those cut on the straight grain. Something to do with the way its stretches.

    Hopefully this gives you more direction! Thanks for your comment!

    1. Thanks for answering my questions. I figured the overcast seam finish would not hold well with regular machine washing, just needed some confirmation.

      I see because bias almost doesn’t fray it doesn’t need to be turned in. That’s really clever.

      Thanks a mil Sunni.

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