Why Does Thread Keep Bunching Underneath My Fabric?

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Bobbin thread bunching, or ‘bird nesting,’ is one of the most annoying sewing machine problems ever! It’s not fun to sit and unpick that pile of looped threads underneath your fabric.

Ugh… I feel your pain.

Let me help you try to figure it out. Here are eight reasons why bird nesting can happen underneath your fabric, and what to do about each one.

Your Sewing Machine Is Not Threaded Correctly

Even people who have been sewing for years sometimes thread their sewing machines incorrectly. This is the first thing you should check if your bobbin thread is looping or your stitches do not look right.

Unthread your sewing machine and rethread it from the beginning. Ensure your thread take-up lever is in its highest position, attach your spool of thread, and then pull your thread through your tension discs and thread guides according to the instructions in your user manual. Then, pull your thread through the eye of your needle and leave a four-inch tail of thread.

Your Thread Tails Are Too Short

If the thread tails that come out of your bobbin are shorter than two inches, they may get sucked into your sewing machine when you begin to sew. This can cause thread bunching underneath your fabric. Try to start with at least three- to four-inch thread tails or hold the thread tails until you have sewn a couple of stitches. This is especially important if you’re sewing with knit fabric.

Also Read: How to Sew Stretchy Fabric Without Losing Your Mind

Your Thread Tension Is Too Tight

Your thread tension should be adjusted for different weights of fabric and thread. Make sure that you are using the same weight thread in both your bobbin and upper thread. If you don’t, your tension can be uneven and cause you to get bunched-up thread under your fabric.

Sewing machine manufacturers suggest that you don’t mess with your bobbin thread tension too much, but you should adjust your upper thread tension if you keep getting bunched up thread underneath your fabric. If your tension is too tight, it can pull your thread and break it. Turn your tension dial counterclockwise to loosen it. If you can’t seem to get your tension right, a sewing machine repair technician can reset your bobbin tension, or you can make small adjustments yourself.

Your Feed Dogs Are Not Up

The feed dogs are what pull your fabric through your sewing machine. They are the little teeth you see sticking up from your throat plate underneath your presser foot. Most sewing machines allow you to lower your feed dogs for freehand sewing or if you’re sewing on delicate fabric. However, if you forget to raise your feed dogs back to their normal position after a sewing project, you can get bobbin thread looping underneath your fabric the next time you sew. Without your feed dogs, your fabric will not move, and your stitches will keep forming in one location.

Your Presser Foot Is Not Down

Your feed dogs need to be up, and your presser foot lowered, to properly feed your fabric through your sewing machine. If you forget to put your presser foot down before you sew, thread looping or bunching can happen underneath your fabric. Many computerized sewing machines will not sew if you do not lower your presser foot first. That’s a nice feature to look for in a sewing machine!

Your Spool Cap Is Missing or Not Secure

Your spool cap prevents your spool of thread from vibrating and bouncing out of control while you sew. If you’re not using a spool cap, your thread can feed through your sewing machine unevenly and cause thread bunching underneath your fabric. Always use a spool cap but don’t make it so tight that your thread can’t come off your spool freely.

Your Bobbin Case Is Full of Lint

Lint builds up in your bobbin case as you sew. It can get in the way of your needle and prevent the hook in your bobbin case from forming stitches properly. Clean your sewing machine frequently to ensure you don’t get bunched-up thread under your fabric.

Your Bobbin Is Not Inserted Correctly

Your sewing machine might still form stitches if you insert your bobbin backward, but your stitches won’t look right. If you are getting bobbin thread bunching under your fabric, your bobbin might be inserted backward. Some sewing machines require your thread to go clockwise in your bobbin case, and some require it to go counterclockwise. Check your user manual to see which direction is required for your sewing machine. There may also be a diagram of which direction it is supposed to go near the bobbin housing on your sewing machine.

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Why does thread keep bunching underneath my fabric? Sewing Machine Troubleshooting
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32 Comments on “Why Does Thread Keep Bunching Underneath My Fabric?”

  1. My nest is only when I start then back space , and proceed forward sewing.
    Then when finished I find on both ends of back spaces this rats nest.
    This is a new Bernina machine .

    1. I’m told by “the experts” to sew a small fabric leader to the start of your seam then when you get to the actual seam edge and then reverse and then go forward, the bunching should be eliminated. Haven’t tried it yet. Makes sense, but why???

      This was never an issue on my old Singer, but a major pain with my new Janome.

        1. If our sewing machine only has one stitch plate that needle goes through, ie does straight & zigzag stitches then fabric at start ( or very close to the edge) can be pushed down into this opening.
          If you have the ability to switch to a zero stitch plate like my Bernina will help.
          If can’t change the stitch plate then use a starter fabric that can sew from middle then your project then there is no edge to get stuck.

  2. My under thread keeps bunching up. I’ve cleaned the bobbin case and underneath, machine is threaded correctly, etc. Only happens when I do quilting. This is. Bernette 82e machine

    1. I have a BERNINA 66e. Bunching only happens when trying to sew stretch fabric, straight, zig-zag and border stitching. Happens every 5cm. Impossible! So so frustrating! I come to solution it needs a service to re-set all tension. ?.. I have done the cleaning, pulled it apart so many times, but I just can’t get it to behave. I am having problems finding a sewing machine repairer, in SEQld…

  3. Brand new Singer machine. My frustration with this bird nesting is off the charts. Can’t find the problem, worked on it for months. Seems to be when I use cotton, when I’m quilting. It is causing an enormous amount of wasted time and took the fun out of quilting. Now this new machine has been sitting for 9 months unused. Saddens me. It was a Christmas gift from my hubby.

    1. Good evening,

      I am experiencing the same issue with my singer! It’s not the super expensive model, but my first singer I purchased in 1987 didn’t do this until 2021 when I bought my 2nd one. So sad : (

      I’m thinking these Late model Singers were not a good product like they were a while back. Sadly, I will return mine.

  4. I’m using an old Kenmore Ultra Stitch 6 and get bunching underneath whenever I use reverse and then go forward again. Machine is threaded perfectly and was just serviced last week. ‘Bout ready to burn my house down I’m so angry. Can’t even stitche a straight line without the machine throwing a tantrum. Thought it might be because its so old but reading thru these comments, everyone seems to have it no matter what machine.

    1. The quick fix to this is not to use reverse. Hold the fabric in place for a few stitches rather than back stitching to tie off.

  5. BERNETTE 66..Botton bunching nest and jamming, plus some pulling fabric down jamming into bobbin works. Cleaned, oiled. Only with stretch stitching??? Happening since new machine…. . Tried changing needles (stretch), change bobbin rethreading and rewinding thread, sew with paper backing. Frustrated totally.

    1. I wonder if the thread is jumping out of the tension discs when the machine reverses for the stretch stitch. They a thread net or adjusting your tension.

  6. Could it be old thread? I had so much thread given to me, I soon discovered it gets old from my sister-in-law who quilts. I threw them all away when I got my new Bernina Machine. I only use Gutterman or Mettler brands now whenever possible.

    1. A spool cap is a little plastic disc that has a hole in the center of it. You put it on your spool pin to hold your thread in place.

      1. What is a spool pin? Is that the pin/post that the reel of thread sits on? If so my reel would not stay on my machine without one, which is in place 24/7. (My thread reel sits in place sideways.)

        1. Yes, it’s where you put your thread. Some machines have a horizontal spool pin and others have a vertical one. The spool cap is essential for horizontal spool pins.

          1. Thank you that is as I thought. I use one always as my machine has a horizonal reel. I was just not knowing the names used.

  7. Lately when I sew, the bobbin thread is loose as I sew top stitch is fine. Can’t figure it out. Never did that before. Am wondering if type of thread has anything to do with it. I have always used regular thread that’s 50% cotton and 50% pollester. Lately I have not been able to find that ratio type of thread. And that’s when I started having this problem

    1. This is what an article from WeAllSew from Bernina said
      If sewer is only having birds nest under the fabric at the beginning of your work, is due most likely to not holding onto the upper thread and bobbin thread behind the needle as you take your first stitch.
      If the bird nests happen also in the middle of your work, make sure your foot is down. Seems logical, but on thick material or seams we may not realize the foot is not down.
      If you have a hands free knee lift, make sure you are not accidentally touching the knee lift with your knee. this would be lifting the pressure foot in the middle of stitches.
      Lint can cause problems with tension, clean and oil your machine per owners manual- take care of your sewing machine.
      I use only high quality thread from my dealer, same for needles.
      Why mess up our machines for the simple price of new needle – correct size and type for your new projects.
      If all else fails take your machine to be serviced.
      Now a days, you get what you pay for.
      I got the Bernina B435, it will sew like butter
      through the thickest stuff, the features I needed of the same higher prices machines but this has everything and more than what I need to sew
      for lowest price. 🙂

      Happy sewing. Hope this helps someone

  8. Or the upper thread is not threaded properly
    Or your needle is bent.
    ((Always change your needle and rethread your machine. ))
    Or you are using cheap, old or dry rotted thread.
    Bobbins being inserted backwards is a major cause of this.

  9. What if the nesting on the back only happens at or near a corner of cotton fabric? I find corners on napkins tricky for that reason!

  10. Pingback: Was Machen Sie, Wenn Ihre Nähmaschine Einröstet? – Tech Update
  11. I was using a fancy #11 stich on my Brother CS-6000i and it bunched up–I completely disassembled it and put it back together (watching YouTUbes to make sure I did it right. now instead of pulling up the bobbin thread it just jams on the upper thread. Any suggestions—I spent hours trying to figure this out and I am as frustrated as many others on this “thread”

  12. Something else that I discovered, at least on my machine, is that if the needle is inserted backward, then the tension can be off and end thread will bunch up.

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