Articles, Blog

How To Create A Flatlock Stitch (Serger / Overlock Machine)

October 9, 2019

Hey Everyone! This is Sarah with Sewing Parts and today we’re going to be doing another serger tutorial. We’re going to be
talking about flatlock stitches. We’re going to be going over a 3 thread and a 2 thread
flatlock stitch. And I’m going to show you how to insert and use the spreader converter
for that 2 thread flatlock. Now you see this all the time in athletic wear, and that’s
because it creates a less bulky seam and it kind of looks really cool. So, I’m going to
show you how to start, what settings you need, and we’re going to get ready to serge. So,
first we’re going to do a basic flatlock stitch. This is a 3 thread. In our needle we have
white, our upper looper is a multicolored thread, and our lower looper is going to be
a black thread. Important thing you need to know, our blade is disengaged, we’re not using
it. But our stitch finger is engaged. Right now I have the left needle in use and my tension
is at a zero. The trick to flatlock is to have zero in your needle. And my upper and
lower looper are both 8. So, here we go. And when you’re guiding this, you just want to
pay attention to the stitch finger and make sure you have about 1/8th of an inch hanging
over the edge. And you’ll see in the close up how that looks. I’m just going to guide
it. And you can see here I have wrong sides together. This is really common in sportswear,
but it’s also a great decorative element to have. So here we go. Let’s take a look. So
this is the upper looper thread. This multicolored. White is the needle thread and black is the
lower looper. Now what I’m going to do here, and this is very important, to make the flatlock
work, I’m just going to open it up like this, which is why having the loose needle tension
is so important because that’s what allows you to open this up. So, I’ll open it up like
this and then on the front it’s flat. That’s a flatlock stitch. Very basic, very easy.
So, with some sergers you have the option to convert it into a 2 thread flatlock and
that’s where this little spreader, sometimes called a converter comes in. And you just
pop it in, and just push it a little bit back, and then bring the little bar in through the
upper looper hole. SO what you’re using is, you’re going to use your lower looper thread
and you’re going to use your left needle thread to create a flatlock that is less bulky and
uses up less thread. So, now that we have that all squared away, we can start sewing.
So, just as before, you want to let the thread hang over the edge. And with this, this isn’t
really ideal for seams, it’s more of like a decorative element if you want that cool
flatlock look. Here, all the thread is kind of hanging over. On the back you have a latter
stitch. Latter stitch. And on the front, once it lays flat, you have to pull it, you have
the flatlock 2 thread. So, here’s an example where it’s a little easier to see. You can
see that the thread is really hanging over the edge. The other one had a lot of print,
I didn’t know if that one was a little too confusing. So, here, when you stretch it all
out, you can see that it lays flat. So it’s like the flat lock you see on sportswear.
So, that’s how you do a flatlock stitch on your serger. For more serger accessories or
thread, visit us online at Or to just hang out with our sewing community,
visit us on facebook at or on twitter @sewingparts, on instagram or
google plus, and be sure to subscribe right below for more sewing videos.


  • Reply Endless Dzns by Carrie November 6, 2013 at 4:46 pm

    Sarah, this was yet another great tutorial! Thanks for the link for the thread you used!

  • Reply Dama Darby November 6, 2013 at 7:58 pm

    Wow, love this video. I have the same machine. Never proper training. Honestly I didn't know how to move my blade. Thanks for showing that. I love this new flat lock stitch. I want to add it to my pillowcase mission dresses. Called that, but I don't use pillowcases, just reg material. Can make them for like a $1.25 each that way. Thanks!

  • Reply Paul McCoy November 6, 2013 at 8:15 pm

    It's great that you showed this but I'm unclear as to how it works for seams since you basically only showed the decorative (folded edge). I've always tended to straight-stitch my seams then finish with serger but I thought a serger stitch is supposed to be strong enough.

  • Reply Sewing Parts Online November 6, 2013 at 8:38 pm

    Hi! It's the same thing for creating a seam, except you have two raw edges together. You still have the wrong sides together and you still want the stitches to hang over the fabric. A 3 thread is great for seams, however a 2 thread isn't as secure and is more for decoration and saving thread.

  • Reply Sewing Parts Online November 6, 2013 at 8:38 pm

    Glad we could help and good luck on your dresses!

  • Reply Sewing Parts Online November 6, 2013 at 8:39 pm

    Thank you for watching, Carrie!!

  • Reply Carlyn Holmes November 12, 2013 at 1:54 pm

    Really good information. I've learned many things from your tutorials. Thanks!!!

  • Reply Connie Tang November 30, 2013 at 10:24 pm

    Can I use this stitch in place of a cover stitch?

  • Reply Connie Tang November 30, 2013 at 10:27 pm

    Can this stitch be used in place of a cover stitch? I don't want to hand to buy a second machine.

  • Reply Gursahib Sohi December 13, 2013 at 4:44 pm

    i m your fan.

  • Reply jaspermatty February 2, 2014 at 9:18 pm

    What is a stitch finger-do all sergers have one?

  • Reply Evandro Souza February 20, 2014 at 6:30 pm


  • Reply louzan May 8, 2014 at 10:07 pm

    please can you tell me if this machine can do a coverstitch??

  • Reply njctmmb August 9, 2014 at 10:30 pm

    What is a stitch finger?

  • Reply Mary Enos August 10, 2014 at 10:39 pm

    That was informative…I have a Brother 1034D and I don't care for the manual that accompanys it….too confusing….This looked so simple…Do you have any that show how to add ribbon detail (for instance to pillows)?

  • Reply Jovienne Jonerson August 23, 2014 at 8:57 pm

    Thank you so much for this informative video. I was wondering if I could do this with my Janome Serger MyLock 203? I tried to do and I couldn't figure it out? Please help…. Thanks again!

  • Reply Tina Beauvais October 1, 2014 at 6:44 pm

    Why is it important for the blade to be disengaged for the 3 thread technique?

  • Reply John James JR November 5, 2014 at 6:32 pm

    Do i need to get a flatlock stitching machine?

  • Reply Una mexicana en Mexico December 23, 2014 at 4:28 am

    I have a serger janome 9102 and I want to know if the plate is S or R? to make flatolock stitch

  • Reply Rose Hep January 14, 2015 at 3:31 pm

    I have a Singer 14U64A, but it doesn't have a stitch finger or the two-needle converter. 
    I think the manual describes your "flatlock" stitch as a "variation" stitch for 3 ornamental threads.  Am I correct?  I'd try it out myself, but my workspace is currently covered in a huge tie-dye operation…

  • Reply Licazy February 20, 2015 at 4:15 pm

    I have this machine for a long time, I never knew how to do that.

  • Reply Frances Hall March 18, 2015 at 12:34 pm

    Would this stitch be okay on stretch lycra?

  • Reply Luke Yorke April 8, 2015 at 7:55 pm

    hey I have a Janome 9200D overlocker, can I get a spreader for this so I can 2 thread flatlock?

  • Reply Namilea LOTI May 22, 2015 at 7:42 pm

    How can you do this with 2 pieces of material? In the video you just have 1 piece folded over, can I sew 2 pieces together doing this?

  • Reply Laurie Is June 24, 2015 at 7:58 pm

    hey there, Can I make quality yoga pants with this technique? The inseam and crotch seams in higher end yoga pants usually use a flatlock.. Would this stitch be strong enough for the seam in Yoga pants?

  • Reply Edward Husar August 15, 2015 at 4:41 am

    With the first flat lock example, could you do the same with two loose ends and engage the cutter?

  • Reply Donna September 23, 2015 at 9:16 pm

    I am looking for a stitch that does not show the squizzle on the front.

  • Reply Mags Nash November 22, 2015 at 10:55 pm

    Thanks very informative indeed. I'm very new to surging, and it's all a learning curve.

  • Reply ssarryo November 29, 2015 at 6:12 am

    Thanks for the help! This method actually works on my serger. I tried the instructions for flat-locking as explained in my serger manual, but they didn't work. Thanks again! 🙂

  • Reply Greg Nixon January 5, 2016 at 2:33 am

    Hi What is the brand and style of that machine?

  • Reply Elysia B March 14, 2016 at 5:32 am

    my goodness those were some great, clear, and insightful tips…I am
    brand new to serging and I would love to learn more from you….sharing
    your settings and setup would be so helpful in the videos…but taking
    the time to share things you are thinking and what you have learned
    about serging is so helpful and will definitely keep your viewers coming
    back for more more more…..

    I had to subscribe when I saw you cared enough to clearly talk us
    through the process…do you do decorative serging…or have you learned
    many ways to use your serger for decoration…brother gives such a
    crappy overview on what all you can do with the serger..settings
    troubleshooting etc…it would be so helpful to have a channel full of
    tips techniques and how you overcame issues with your serger so as to
    keep us from encountering them.

    all the best and thanks for your time and sharing and caring!

  • Reply Elysia B March 14, 2016 at 5:42 am

    Sara being new to serging…I kind of dont want to have to take out a needle thread back and forth for different serging….Can you do a 4 thread flatlock on a serger? If so, what would your settings/set up be for that? Thanks for your help! Please be sure to add serger tips and techniques that you have and that you encounter or learn…especially trouble shooting 🙂 It would help us new people sooooo much and old too I'm guessing…who doesn't love new insight! Love your channel and I'm loving your serger series and praying you'll keep adding to that playlist forever…:-)


  • Reply Elysia B March 14, 2016 at 5:46 am

    Does most sergers come with the 2 thread spreader do hickey? I am really hating my brother manual…all the other languages on the page and uneasy to follow…I just hate it…do your recommend any good reference books? Can you add some videos with you creating garments and functional or even sellable items with the serger? Thanks for your patience and caring …you show that you care about your views by providing clear and in depth insight…and that's why I'll always be a fan of your channel…thanks again!

  • Reply bauman11 June 30, 2016 at 2:50 pm

    I do need a spreader but I don't think my machine will equip one. It's a janome juno 3434d.

  • Reply VJkane July 1, 2016 at 3:04 am

    I recognize the benefits but flatlock stitching makes everything look like it came from the discount rack at Walmart.

  • Reply That's Sew Maisie July 19, 2016 at 10:14 am

    Could you please show us how to do a cover stitch if thats what it called? What you see on leotards etc. I can't find anything on it. Its where the right side has two needle stitching and the other wrong side looks serged. Ive looked in the manual and everywhere to find how you do it

  • Reply Michele September 22, 2016 at 9:06 pm

    did she say the tensions ?

  • Reply anna avidan November 8, 2016 at 4:53 am

    what kind of threads should I use for my senger?

  • Reply Joyce Weaver February 13, 2017 at 3:10 pm

    where do I get a spreader?
    babylock ecilipse

  • Reply Lenae Falcone April 9, 2017 at 1:26 pm

    what are your side tension and stitch length set at?

  • Reply Richard Myhre April 19, 2017 at 11:07 pm

    I just got my Singer ProFinish machine. I just watched the rolled hem tutorial. My question is, can you do a rolled hem using the right needle without removing the left needle?

  • Reply krmna Bars April 28, 2017 at 7:22 am

    Overlock is for clean edges ; the threads do not stickup on edges (when knives cut, cleaning fabric), in order to sew 2 pices you need security thread line/ or sew in 2 machines, secure fabric with strait stitch and clean edges with overlock!!., if you want use cut you fabric overlock does too for shape you craft.and can use security stitch too (other extra thread cone)

  • Reply Robert Lee April 30, 2017 at 8:55 pm

    Genius! I tried it on my new Juke, thank you tons!

  • Reply Patsy Dease July 30, 2017 at 10:46 pm

    What kind of thread for my Genome8002d for the new polyester knits

  • Reply Shamim Khan September 20, 2017 at 1:06 pm


  • Reply Niki Nolasco March 9, 2018 at 12:28 am

    Hi! Does this flatlock stitch compromise the hem? Like if I use it on a side panel for leggings?? Thanks!

  • Reply Jeane Davis September 26, 2018 at 6:51 pm

    Thank you for this video. I have learned a lot and have been using a serge for over 20 years. I love learning about my machines. Again thank you

  • Reply Kate Regehr December 31, 2018 at 1:49 am


  • Reply Sherri B May 26, 2019 at 8:26 pm

    can you do that on a serger that does not flatlock?

  • Reply medilania nunez October 5, 2019 at 10:14 pm

    My mom has an Overlock singer 14T948DS and she has a lot of time trying to make a small stitch with her to make the stitch 1/4 inch wide this stitch is possible and if it can tell me how it is done thanks

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