Serging Technique: 3 Thread French Seam for Lace and Delicates

I don’t know how “kosher” this technique is.  No one taught it to me, I haven’t seen it around.  A long time ago I decided that sewing something “right” means it fits, it looks good, it doesn’t fall apart and it will wash.  Everything else is academic.

It’s a french seam- but the first line of stitching is a 3-thread serging stitch.  This lends durability to a lighter-weight fabric, binds in the raw edge and trims the seam to a reliable width from one end to the other.   It also adds some bulk, so if that’s not what you’re after then try a traditional French seam.  My fabric is too holey and light, the extra heft of serging means I can wear it longer.

My machine is usually set to 4-thread serging.  I leave the needle threaded when I loosen it; that means the needle can’t slip into the lower reaches of my machine.  Once it’s free, I cut the thread and remove the needle.

Since it’s going right back on the machine after I serge the seam, I stuck the needle in a piece of fleece I keep under one of the spools for just such an occasion.  It’s not a good idea to let your needles become “uneven,” however.  As a general rule, you want both needles to wear at the same rate, and replace them at the same time for best stitch quality.

Wrong sides together, serge the seam.  I find this technique works best on straight or gently curved seams.

Press the seam to one side.  Then fold the fabric so it’s right sides together and the serging is on the inside.  Press it again.

Stitch a 1/4″ seam.  Or slightly wider than your serged seam.  My 3-thread is a hair under 1/4″, so sewing my second seam at 1/4″ works for me.   If I start out with a 1/2″ seam allowance and sew it this way, everything works out like sunshine.

Wrong side.  Press the seam to one side.  Stitch down if desired.

Most of the time, I find lace fabrics are very very forgiving; stitching tends to disappear into the texture of the fabric.

I have used this on many weights and textures of fabric, and it consistently yields clean and durable results.  I used it on the Lacewing Top I’ll show you tomorrow!

Have you ever done this?  What is “right” in sewing?

In other news, Liza Jane made a beautifully fitted and and well-executed pair of pink linen trousers.  Well done, Liza Jane! (And thank you so much for your kind words! :))  The trousers look fantastic, complete with a discreet flower button on the front.  Such fun.  Check out her write up on the pants and the block service from the Consulting Dressmaker.


  1. I use french seams fairly often but I hadn’t thought about using the overlocker for the first pass. I want to make myself a lace jacket so I’ll remember this technique for when I do that.

    • Wicked. Will you blog it? What kind of jacket? I always want a lace jacket, but just the right fabric and pattern haven’t come and slapped me upside my head yet…

  2. I have seen this published in a book or two or three, of course I have no idea which ones. I can look them up and post later if you are interested.

    • They’re pretty useful tools.. I got one a few years ago when I wasn’t sure if I was really *that* into sewing or not… But somehow having a $600 machine (I don’t remember how much I paid for it, but something like that) sitting there staring at me meant I felt the need to know everything about it and use it.. So I do. :)

  3. I’ve seen something like this done with a very compacted zig-zag stitch when making children’s heirloom garments from fine cottons. It makes perfect sense! I think your serger technique would be even better. If only I had a serger!

    • The zig-zag would work pretty well I think, maybe even better in some instances. The bummer would be trimming but it’s not such a big deal..

  4. That’s a great idea—I have contemplated this, but I don’t think I’ve ever actually tried it.

    We spend a lot of time wrangling about the “right” way to do something (often “right” meaning RTW), but really what it comes down to is 1) does it work, and 2) does it look good.

    As far as I’m concerned this technique is both. :)

    • Yeah for sure. I forgot “does it look good” as one of my criteria, but of course, that’s so important I edited to add.. Thank you for reminding me. :)

  5. Perfectly “legal” to do it this way. It used to be advised that you sew the first pass, trim seam, then zigzag or — horrors! — hand whip the seam edges for ravelly wovens, before turning for the final pass on a French seam. At least, that’s how I remember my junior-high home ec teacher Miss Brooks lecturing us … I try not to think about her too much, but she keeps cropping up in my nightmares.

    • Sigh… I can’t tell you how many people come to my beginner’s classes as a sort of “rehab”… Those Mrs Brooks types ruin so many people for sewing, such a shame.

      • I got lucky, my junior-high home ec teacher (Mrs. Peterson) was great, she let me sew at my own pace & just kinda left me alone since I’d already had my own machine for a few years at that point.

  6. If you do this on very sheer fabrics, make it a rolled hem first and then flip and sew. The seam will be very dainty and light and strong. It is kosher, it works and saves lots of tears…the wet kind and the rip kind. Now we have all learned a new tip…thanks, Steph!

    • OOoooOooh la la- a rolled hem would be so tiny ! It’d be the simple and easy way to do a fine french seam. Thanks for that, next time I’m working with a sheer I’ll do it. :)

  7. Great post! I bought my first serger yesterday and am hoping to make a few lace tops this summer so, this is perfect! Thanks for sharing :-)

    • I can’t remember the last lace top I had, but this one makes me think I should whip up a few more. It’s so sweet, and the sewing took no time at all.

  8. I do this all the time. It’s a great way to avoid the “pokeys”–frayed threads that stick out of the right side of a French seam. Also, it trims the seam allowance for you!

  9. Kindred seamstresses! I do this too, and I also was not taught it, and have never read it. It just made sense! It’s lovely to get affirmation from another seamstress (and such an experienced one!) that this technique works.

    • Heheheh. Funny the little things we keep quiet about… The first time I did it, I was looking around for the sewing police… But they never came.

    • Well, Mrs C, it was a sample and I wasn’t paying attention. So naturally it would be nicely matched. On the actual garment, well, I hope you don’t think less of me. I was *trying* to match and it didn’t happen.. But I think it still came out well…

  10. I get pokey’s a lot on kids garments cause I am usually trying to sew with a small scrap, reducing my seam allowance to fit the pattern on the fabric. Super trick. Loving those hot pink linen pants… Obviously that pant block did the trick, congrats. What a great class that would make :-)

  11. I love the gorgeous pants that Liza Jane made, it’s a good job there are no ‘sewing police’ or I would be in serious trouble, hardly anything I make follows the rules, my sewing is a combination of making an apron at school, stuff from my mum and teaching myself the rest! But it usually turns out ok in the end! X

  12. Pingback: Finished Object: Lacewing Top + Hack + Lace Fabric Giveaway « 3 Hours Past the Edge of the World

  13. I’ve read about it in the book Sewing with an overlock from Singer, but I’ve never used it. I have never been very confident in french seams on frayable fabric, but this is a great tip to make this kind of seams last longer. Thanks for the reminder! The lace is beautiful. And I love what you’re making in the header photo.

  14. Thanks for the tip Steph.I’m planning on making a lace dress shortly And I will most certainly try this out. As for the sewing police I’m sure I do many things the “wrong” way but it works for me so meh!

  15. So reassuring to know that ever experienced seamstresses look over their shoulder for the sewing police! Being almost entirely self- and internet-taught, my first criterion was “does it even hold together?” As I’ve gotten more sewing time under my belt, I am slowly adding more criteria.

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