Best Serger Tension Tips (Bonus: Unpick it!)

Just because I know that sometimes a relationship with a serger can be frustrating (as any other relationship, in fact), I’d like to share with you some of my little tips and tricks about serger’s tensions troubleshooting, learnt along my sewing journey; you’ll get the most if you’ll take a look at my 10 best beginner’s tips too, one of my most visited and pinned posts!

And this carries us to today’s topics:

Best serger tension tips

Serger Pepper - Best Serger Tension tips - title

A couple of things to say first:

What is tension, on a serger?

Tension on a serger (like on a sewing machine) is what decides the amount of thread that goes into the seam, it’s related to thread’s speed: if you increase tension, less thread will flow into the seam, and vice versa.

It depends on many factors, like the type of thread, type of seam, fabric thickness, just to name some of them.

Just to be practical, you’ll probably need to loosen your tensions with:

  • heavier thread
  • thicker fabric
  • longer stitch (this mainly affects looper’s tensions)
  • narrower stitch (this mainly affects looper’s tensions)

Wait! First things first: you’ll need a threaded serger (need some help? Check my tutorial!)

When you buy a serger, usually, you’ve got it perfectly threaded!

A lot of people start sewing without taking more than a quick look to all those threads and their routes… then something goes wrong and… panic!

No need to! Let’s roll up our sleeves, we’ve got some work to do 🙂

… well, in fact, I’ve already done the hard work for you…

Just a side note: maybe your serger isn’t exactly like mine (I have a Necchi 181, for the record) but they’re all similar. If you’re stuck, please ask for help!

Serger Pepper - Best Serger Tension tips - threading

Let’s take a look at this first photo: you can see that, on my Serger, the color code is:

green (left needle)

yellow (right needle)

blue (upper looper)

violet (lower looper)

I’ve threaded my serger with spools of thread with the same colors, to give you an easy reference to check when you’re in trouble…

Say “Thanks, Mamma” and Pin this, quickly!

;D

When you’ll be serging with 4 spools of the same color (or nearly), it will be harder to understand which tension wheel you have to turn, and in which direction

Having pinned and checked this reference tutorial will guide you to fix it without doubts and in a short time, leaving you a lot of time for creating, having a coffee, go out with friends, you decide! Let’s share with you my Best Serger Tension tips

Find the balance: the Perfect Seam!

(a.k.a. Best Serger Tension tips)

The following one is the perfect 4-thread seam: you can see that looper’s threads are meeting exactly on fabric’s edge and there are no puckers on needle threads, that look like two rows of straight stitches on right side…… and tiny loops on the wrong side:

Serger Pepper - Best Serger Tension tips - perfect tension

Serger Pepper - Best Serger Tension tips - perfect tension

 

But what if tensions are messed up?

As a rule of thumb, on most sergers, you should start with all four knobs on 4, usually it’s a great starting point for a 4-thread stitching.

Then, you have to take a look to your seam: is that perfectly balanced as mine? Well, I can go home, you’re great 🙂
If it’s not perfect, and you’re a visual person like me, you should take a look at some variations and understand what causes them: this will help you to learn which knob you’ll need to touch later!

To analyze tensions troubleshooting in-depth, I’ve sewn some samples putting tensions knobs on 0 (zero) and 9 (nine), just to see what happens in both front and back of the seam. You won’t find yourself in those extreme situations, but this will help you to understand how tension works.

  • Maybe it’s obvious, but you need to tighten tension (higher number) if you see loops and to loosen it (go to a lower number) when you can barely see the thread , that pulls and distorts everything.
  • Always start with small shifts of knobs, until you won’t “have an eye”

Let’s have a look at how your seams look like on front and back sides when tensions are set to “0” (first two photos of each group, front and back) or to “9” (second set of two pics, front and back), on:

– Left Needle (green):

Too low tension:

The lower row of stitches (green left needle) is no more a straight line, pulled up from the looper’s (blue in front, violet in back) threads. To fix it, just turn your left needle (green) knob to a higher number.

Serger Pepper - Best Serger Tension tips - left needle loose

Too high tension:

And here you can see the green thread too tight: on the front, it’s pulling out the violet looper, on the back side you can barely see some green spot! Turn down your left needle knob and everything will go better!

Serger Pepper - Best Serger Tension tips - left needle too tight

– Right Needle (Yellow):

Too low tension:

Look at those yellow loops on both sides… it’s obviously needing a tightening action on left needle knob, to get back to a straight yellow seam line !

Serger Pepper - Best Serger Tension tips - right needle loose

Too high tension:

Now you see how this yellow thread is pulling out our violet thread (lower looper) on front while on the back is disappearing?

Action needed: loosen right needle knob!

Serger Pepper - Best Serger Tension tips - right needle too tight

– Upper Looper (Blue):

Too low tension:

Loopers should meet each other on fabric’s edge, midway. Here the lower looper is so loose that is looping on the back side… better turn its knob to a higher number!

Serger Pepper - Best Serger Tension tips - upper looper loose

Too high tension:

And this is the opposite situation: a too tightened upper looper tension is pulling up green left needle thread, distorting it, while it’s pulling a violet thread on the front side

Serger Pepper - Best Serger Tension tips - upper looper too tight

– Lower Looper (Violet):

Too low tension:

Last one: the lower looper acts as the upper looper, just be sure to touch the right knob:

Remember that your Upper Looper (blue) sits on front (or up) side of the seam,

while Lower Looper (violet) is on the back (or low) side of the seam .

On the first couple of pics you can see a lower looper without enough tension:

Serger Pepper - Best Serger Tension tips - lower looper loose

Too high tension:

And here the same lower looper (violet thread) is too tight: you can’t see it in front of the seam and it pulls the upper looper (blue) and the left needle (green) on back of the seam, failing to meet the other looper’s thread on the edge of the fabric!

Serger Pepper - Best Serger Tension tips - lower looper too tight

Obviously, in real life, you’ll experience a combination of two or three thread’s tensions messed up.

When I have to fix more tensions, I like to follow this order:

  1. fix left needle‘s tension
  2. fix loopers tensions
  3. fix right needle‘s tension.

But, what if your tensions are messed up but you think tension disks are correctly set?

Here are some of the questions I usually ask myself:

  1. Do I have a thread caught under a cone or spool?
  2. Is the thread following a wrong way, skipping a thread guide?
  3. Are there any threads that wrap twice around a thread guide?
  4. Did I check my needle condition? Is it inserted in the right way, have I chosen the right one (right type and size, basing on fabric)?
  5. Did I check for tangled thread on the stitch fingers or feed dogs, or loopers?
  6. Is my thread guide pole in its higher position (the first thread guide right after the spools)?
  7. Did I check for lint or bird’s nests of thread between tension disks? Your serger loves a good air blow from a compressor or a simple canned air!
  8. Is thread perfectly seating on tension disks? Floss them, eventually, just to be sure!

-0O0-

And now… what about My Bonus Tip for you… here’s my animated infographic about

how to unpick a 4-thread serger seam

Pin it now, you’ll thank me later 😉

I hope you enjoyed my little rant about serger’s tensions. Let me know if something was unclear!

I’ll be more than pleased to answer to your comments if you’ll be so nice to leave me a couple of words about how is your serger’s relationship… Or anything else!

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About the Author:

Hi there! I love sewing, creating my own patterns and refashioning pre-loved clothes... If you love the same things, why not be friends? See you on Pinterest http://Pinterest.com/MammaNene

34 Comments

  1. cucicucicoo April 19, 2014 at 17:46 - Reply

    Great and useful post! I’m just now graduating toa 4-thread serger (I had a 3-thread one before) so this is useful for me! But just FYI, I can’t visualize the infographic at the end. Happy Easter, Irene! 🙂 Lisa

    • Mamma Nene April 19, 2014 at 19:23 - Reply

      Thanks Lisa! It should be fixed, now…
      Is your new serger at home? Or is still traveling to you?

      Hoppy Easter to you LOL

  2. ksgentry April 20, 2014 at 00:59 - Reply

    Love your instructions, maybe I will get brave and pull out my serger that I have had but never used because I am scared!

    • Mamma Nene April 20, 2014 at 10:01 - Reply

      You should! Forget the fear and pull it out! There’s a lot of fun coming with it… 😉

  3. Diane April 22, 2014 at 05:29 - Reply

    Thanks for such a detailed post. Your pictures and explanations are just what I need and I will be saving it for future reference. I just got a new serger last week so am having fun learning about it.

    • Mamma Nene April 22, 2014 at 09:58 - Reply

      Glad you like it, Diane 🙂
      I can feel your joy for your new gadget, I remember I was so happy when I finally got mine… Later this week (on thursday) I’m guest posting on SewMcCool.com… and I’m pretty sure you will love this one too 😉

  4. […] help to locate which thread needs a change in […]

  5. Elise January 1, 2015 at 03:02 - Reply

    Hi!!! I love your blog! It’s helped me through the beginning stages of learning to use my new serger! So thank you!!!!! Wondering if you had any tips for serging through a thick project?? Making some “g-diapers” for a friend and they require 4 layers of fleece and 1 of cotton! Just cant seem to keep the stitches tight and consistent. Thanks for any advice you might have!! And Happy New Year!! 🙂
    Elise

    • Mamma Nene January 11, 2015 at 11:48 - Reply

      Hi Elise!
      I did diapers for my daughter, but using my sewing machine!
      Consider that 4 layers of fleece and 1 of cotton sounds like A LOT to me, I’m not sure if my serger could handle them!
      If I was using a serger I would try:
      1) decrease tension on threads and increase stitches length
      2) play with your presser foot pressure (you should have a screw or knob somewhere, in the back of your serger) but remember to re-set it later, when you’re done!
      3) use a hammer! Yes, a real hammer… Just hammer thick areas you’re going to serge, to flatten them down!
      4) use heavy duty sharp needles (like denim or leather needles)
      5) at least a 90/14 (if not a 100/16) needle
      6) If all else fails, try sewing, then serging above this seam!

      Let me know if this helps you solve your problem!
      Happy New Year to you too,
      Irene

  6. Lynda Vee February 21, 2015 at 03:05 - Reply

    I recently had to replace my old serger and now I am a bit confused with this new one and I can not find this problem in my trouble shooting..
    My serger is a Brother 1034D. The problem I am currently having is I need to sew a straight seam on my sewing machine before I serge the edge ….I have my thread tensions both at 1 1/2 – 2 but when I am done serging and do a slight tug like trying to pull the two fabrics apart while looking at the right side with the vertical seam in the center…when you slightly pull can see the seam threads
    I am sewing for charity the pillowcase dresses using fat quarters and sewing 16 strips together would be so much easier if the serger made a “tighter seam”.
    I am stitching 2 pieces of cotton fabric together – the loopers look perfect no tugging, no loose threads, but I really would like the seam thread tighter …
    Any suggestions?

    • Mamma Nene February 23, 2015 at 13:45 - Reply

      Hi Lynda!
      The first thing I would try is… re-thread your serger, using different threads (please do not knot-thread it, but do it the old-fashioned way, like shown here: http://bit.ly/ReThreadSerger).
      Change your needles with fresh ones too, double chcecking they are going all the way up before you close the screws.
      Check your needles’ tensions and, maybe, tighten them a bit…
      I would love to hear back from you!
      Thanks Lynda and… happy sewing 😉

  7. Trudy March 5, 2015 at 19:05 - Reply

    Thank you for the info. However,I am still having problems. After stitching, I can still pull on the seams and they separate about 1/4″ and the horizontal stitches show through on the right side of the fabric. Any ideas?
    Thanks again!!!!

  8. Carolyn April 2, 2015 at 19:31 - Reply

    I am serging some lightweight knit fabric and am getting some curling under on the back side. I am not intending to do a rolled hem, and it only the back that rolls. I can brush it out with my fingernail to lie flat but it takes time. The seam looks OK but it is messy looking if I don’t brush it out flat. I have tried adjusting my loopers but haven’t had any success. Any advice?

  9. Ursula September 13, 2015 at 15:43 - Reply

    I have a toyota serger and also a new home 434. The New home does pretty nice work but puckers the fabric a bit which is easy to correct when done by ironing which I do anyway but my toyota serger will go happuly along serging when all of a sudden the tension of either upper or lower looper goes out of whack and I have loopy lower and upper loopers in teh seam. I then have to rethread everything. Also on my new home sometimes its all threaded correctly but it doesnt make a chain and using fabric nothing holds and I have to rethread again. What are those problem? Thanks for your help

  10. Melissa October 9, 2015 at 02:23 - Reply

    Help! My left needle tension just doesn’t want to work right! It’s too loose (with loops showing on reverse) but when I tighten the tension incrementally the thread breaks before the problem corrects (about 4). The thread is moving fine off the cone and I have rechecked the threading a million times (and corrected a number of problems). It’s been a day since it came out of the box and I am getting desperate with strips of serged spandex all over my room! I used three different kinds/quality of thread on this dial. Is it broken or am I???

  11. Katrina October 13, 2015 at 03:59 - Reply

    I was just wondering if you could help me with my problem on my serger…. I do a lot of sewing…a nd serging. I have 2 girls and I sew lots of dresses for them and me! So my serger gets used a lot! My needle on the left does not stitch! It seems to all be threaded right but it never stitches so likewise never catches the bottom threads. I have had several needles break on it already. It seems as if something is not right underneath the plate but don’t know what! Do you have an idea of what could be wrong? It does fine on just having the 3 threads sewing. Thanks

  12. TJ Hein November 22, 2015 at 21:05 - Reply

    Hi. I have been working on a flat felt stitch my serger will make the chain so I believe that I have threaded it correctly however when I change the tension to do flatfelt stitch the thread gets in a big knot in front of the needle does this make sense and do you have any suggestions? Thanks TJ

  13. Nancy February 28, 2016 at 22:23 - Reply

    Hi, my right needle thread on my serger is on the outside of the chain, but included in the stitching. What could be causing this? I have changed the needles and retreaded my old Babylock Protege’

  14. Lynn McWilliams April 28, 2016 at 00:37 - Reply

    Hi Mama Nene,

    Do you change tensions with the pressed foot up or down?

  15. Claire May 11, 2016 at 05:19 - Reply

    Hi,
    I’ve been trying to solve a left needle tension (too much loop on back side) for a long time. I now know my manual very well and it did not have the answer, I have googled and googled and still did not find my answer. On my third approach to discovering a thread (pun intended) on Google that could help me identify the issue, I came across your website. With a quick look at your picture and two tries of tension adjustments on my machine, my problem was solved. (My tension for my left needle had to be at 1.5 for some reason while the other three are at 4.)

    Thank you so much for your great detailed picture and solution.

    Claire

  16. Norah May 30, 2016 at 21:29 - Reply

    Hi

    I have a Pfaff five thread serger and I’m having trouble with it skipping stiches with the chain. I have tried new needles have rethreaded many times.. I have also played with the tensions.

    A little bit of background. I took it in for servicing and they replaced the lower knife, everything was good. I changed my thread and since then it has not worked properly. I have changed back to the original thread, but it is still skipping stitches and looping on the bottom thread. Could the problem be the upper knife needs to be changed.

    Hope you can guide me through this. Looking forward to you reply.

    Norah

  17. Rachel November 28, 2016 at 23:39 - Reply

    Hello,

    I have been using my 4 thread overlocker (serger) for some time now but recently I’ve noticed that when I turn the fabric back to the right side and put any stress on the seam (particularly side seams) I can see horizontal treads come through, which doesn’t look very professional!. I have fiddled with every tension dial for each of the threads but I keeps happening! Do you know why this could be?

    Thanks! 🙂

  18. Melissa McDonald December 20, 2016 at 00:43 - Reply

    Hey there hoping for some help! My left needle is not sewing on Double brushed Poly. It sews just fine on other materials (most of the time!) sometimes it’s skipping. It doesn’t matter what I do to my tension it won’t catch, and I’ve changed my needles! Any ideas?!

    • Mamma Nene December 21, 2016 at 19:16 - Reply

      Hi Melissa!
      Are you using a stretch needle? Or just a Universal one? This might be the problem.
      Another thing you can try is stabilizing fabric with some tear-off or soluble stabilizer (like the embroidery stuff) or, if you have any on hand, try with some toilet paper below the fabric.
      I’d love to know how it goes!
      Happy serging,
      Irene // Serger Pepper Designs

  19. Lyn January 4, 2017 at 00:05 - Reply

    Just wanted to thank you for your suggestions. I tried everything or so I thought. Was ready to take my machine in to be worked on because I thought the tension was messed up. My husband was just going to buy me a new serger instead of paying to fix mine which is several years old, but well loved and used. Then the note about the needle being inserted correctly caught my eye. Sure enough, I turned the needles around and tada!! Just like new. Definately something to check first if you break a needle as I did. Thank you.

    • Mamma Nene January 14, 2017 at 11:47 - Reply

      That’s great news, Lyn!
      We have saved a serger, and some money too 😉
      Glad to know I helped you!
      Happy new sewing year,
      Irene // Serger Pepper Designs

  20. Amy P January 6, 2017 at 04:45 - Reply

    This is the BEST serger tension post I’ve found! Your pictures are amazing, clear and detailed! Thank You so much, I’ll be studying this post alongside my new serger to fix my tension! I even had bought four different color threads to try and help me figure out which knob to change but I’m still being challenged. I love to sew but this new serger is making me feel much like a inexperienced seamstress. The challenge is on!

    • Mamma Nene January 14, 2017 at 11:57 - Reply

      Thank you, Amy!
      My best tip is keep on trying, serge over scraps, play with tensions and widths and have fun.
      And ask, if you need help 🙂
      Happy new year, with your new serger!
      Irene // Serger Pepper Designs

  21. holley58 January 8, 2017 at 18:51 - Reply

    Help I can’t get my serger to work. It will not serge only sews a straight stitch!

  22. Ms. G January 31, 2017 at 00:32 - Reply

    Just want to say thank you. I’m so glad this post still exists and came up on top in Google because it solved my problem.
    Needed to tighten the needle.
    Thanks a bunch!!!
    U checked several other websites too and this is by far the most clear, precise and straight-forward guide. Thank you.

  23. aimee February 27, 2017 at 00:22 - Reply

    Great Tutorial, Thank You! bookmarking

    • Irene February 28, 2017 at 20:57 - Reply

      Thanks, Aimee, for your sweet words <3

  24. Pamela April 14, 2017 at 00:12 - Reply

    Hi, I hope you are still answering questions! I am using a used Babylock serger. The tension is erratic. I make adjustments and it seems ok, then it is all out of whack. The loopers are totally off the fabric, both top and bottom. I have adjusted everything again and nothing seems to work. One time it seemed to be from the needle tension, but adjusting that doesn’t seem to help. Do you have any suggestions for me? Oh-I am sewing on a light to medium knit.
    Thanks!
    Pam

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