Why is my bottom stitch bunching up

Why Is My Bottom Stitch Bunching Up?

Thread bunching or birdnesting is a common problem for many sewers, it will cause uneven stitches that will be difficult to get a professional – looking finished project. Thread bunching will occur when the upper and lower threads do not come together smoothly, which will result in a tangled or bunched- up appearance underneath the fabric. There are several factors behind this problem, such as improper thread tension, incorrect or damaged needle, improper threading, incorrect bobbin placement, and issues with the fabric. It will be time-consuming to fix the problem and it requires trial and error, although, with the right techniques and troubleshooting, you can achieve even stitches.

“Thread bunching” occurs on the underside of the fabric, that is because of the lower thread. You can check if the bobbin is sitting correctly in the bobbin case or if you want to replace the bobbin. The cause lies with the upper thread; the upper thread tension is set correctly. The ratio of upper and lower sewing threads should be correct. We have discussed in this article, some reasons for thread bunching, some tips to solve the problem, and some additional tips if the machine is blocked.

Key Takeaways

  • We have discussed in this article, some reasons for thread bunching.
  • We have gone through some solutions to solve the problem.
  • We have also discussed some additional tips for the thread bunching.

What Is Sewing Machine Thread Bunching?

A tangle of thread under fabric is “thread bunching” “bird nesting” or “thread jamming”. It is known as “bird nesting” because the tangled thread resembles a bird’s nest. When you are experiencing this problem, it means, you need to address this problem. It is often seen in the form of small knots or loops of thread appearing on the underside of the fabric. These loops weaken the seam and can cause the fabric to pucker. So, when you have thread bunching, you can stop sewing and fix the problem. Many sewists believe that thread tension is the main cause for this, but there are other reasons which can be the culprit, such as incorrect threading, broken or wrong needle size, bobbin problems, and so on. It will take some time to fix this problem, but it will require some trial and error to get it right. We will try to find out some common reasons for thread bunching and some solutions for this, too.

12 Reasons for Bottom Stitch Bunching up

Thread tension is the main reason for this, however, some other reasons might cause thread bunching. While you are sewing, you should know what causes this problem. we have given below some common causes for this problem:

1. Improper thread tension

Improper thread tension
Improper thread tension

The upper thread tension controls the amount of tension that has applied to the upper thread as it has been sewn into the fabric. when the tension is loose, the upper thread will not be pulled tight enough, which will cause the bobbin thread to not pull properly and it will result in bunching underneath the fabric. If the tension is tight, the upper thread can be pulled tightly and it will cause the bobbin thread to become bunched up as well.

2. An incorrect and damaged needle

An incorrect and damaged needle
An incorrect and damaged needle

If you are doing threading in an incorrect way that is also a reason for the thread bunching up. You should re-thread the machine, so that, you don’t face this problem. If your thread is not going through the tension assembly, try to re-thread it. You will have to remove the thread to start threading from the start. Follow the thread guide. Bring up the pressure feet before you start the threading.

3. The take-up lever is up

The take-up lever is up
The take-up lever is up

The take-up lever pulls the thread all along the sewing machine. When it is not in the correct position, your stitches are bound to start bunching up and causing a mess for your bottom stitch. So make sure your take-up lever is in the uppermost position.

4. Thread tension is not optimal

Thread tension is not optimal
Thread tension is not optimal

When the upper thread tension is loose, the thread will get tangled under the fabric. You can turn the knob clockwise to tighten it up. First, tighten it slightly, then sew on a test fabric. Then tighten it again so that you get it right. If bobbin tension is not tight, bird nesting cannot happen. Most modern machines do not touch the bobbin tension; it will remain a constant.

5. Feed dogs are not up

Feed dogs are not up
Feed dogs are not up

The feed dogs pull your fabric through the sewing machine. They have little teeth that you see sticking up from your throat plate underneath the presser foot. You can lower your feed dogs for freehand sewing when you are sewing delicate fabric. Do not forget to raise feed dogs to the normal position, or your bobbin thread will be looping underneath your fabric. Without feeding dogs, your fabric will not move and your stitches will be forming at one location.

6. The presser foot is not down

The presser foot is not down
The presser foot is not down

Keep your feed dogs up, and your presser foot lowered, to feed your fabric through a sewing machine, or you will experience looping or bunching underneath your fabric. some computerized sewing machines will not sew when you do not lower your presser foot.

7. The spool cap is missing

The spool cap is missing
The spool cap is missing

A spool cap will prevent your spool of thread from vibrating and bouncing out of control as you sew.  While you will be using a spool cap, don’t make it tight, so that your thread can not come off your spool. Your thread can feed through your sewing machine unevenly and this may cause thread bunching underneath the fabric, without a spool cap.

8. Problems with bobbin case

Problems with bobbin case
Problems with bobbin case

There might be problems with the bobbin case which causes your bottom stitch to bunch up. Here are some of the problems that might happen:

  • Full of lint: after a while, your bobbin case will be full of lint, if you keep sewing with your sewing machine. This will get in the way of your needle and prevent the hook in your bobbin case from forming stitches properly. Clean your sewing machine so you don’t get bunched-up thread under your fabric.
  • Damaged bobbin case: double-check to see if the bobbin area is right and good. Clean this up. Make sure that there are no jagged ends.
  • Not inserted properly: if your bobbin is inserted backward, your sewing machine will form stitches, although the stitches will not look right. When the bobbin thread is bunching under the fabric, it might be because the bobbin is inserted backward. Sometimes thread will go clockwise, and sometimes thread will go counterclockwise. You should check the manual of your sewing machine.
  • Threaded incorrectly: if the machine uses a bobbin case, take the bobbin out of the case and re-thread it. Your bobbin thread should be engaged in the bobbin tension. Hold on to the bobbin thread with one hand. If the bobbin drops to the floor, it is because the tension spring is missing.

9. Having the wrong fabric

Having the wrong fabric
Having the wrong fabric

The fabric which is not suitable for the sewing machine may have many thick layers, such as leather, leather. If you have the wrong stabilizer under the embroidery design, it will clog up the needle and can cause bird nesting in machine embroidery.

10. Not doing machine maintenance

Not doing machine maintenance
Not doing machine maintenance

If you have not used the machine or cleaned it recently, the thread will bunch up similarly. You need to take proper maintenance to solve the problem. Try to clean the area under the needle plate, bobbin case, and hook assembly thoroughly. Clean the thread path. Modern sewing machines are needed to be serviced at the repair shop. In some machines, the bobbin tension can be loosened to solve the problem.

11. Positioning is not right

Positioning is not right
Positioning is not right

When you are doing embroidery, you will be using hoops and stabilizers, when the hooping is loose, the fabric can shift and the thread can bunch up.

12. Old machine

Old machine
Old machine

The discs of the tension assembly could be damaged, you can repair them at the repair shop. Maybe you have an old sewing machine; the needle maybe not going to the hook. So, check the setting of your machine.

6 tips to solve the problem

6 Tips to solve the problem
6 tips to solve the problem

 As we have already addressed the problem and the common causes behind it, it is time to go through some solutions, so that, you can sew without any disruptions. Below we have given 6 tips to solve the problem:

1. The upper thread is threaded correctly

If you are threading the upper thread, you should raise the presser foot and hold the thread lightly with your right hand as you pass it through the guides along the marked thread path with your left hand. Check if the upper thread has been threaded correctly. Hold the thread in both hands with light tension. Make sure, the thread is positioned properly between the tension discs on the top of the machine. If it is not positioned correctly, it will not have any tension and it can be pulled under the very first stitch. Check if the upper thread is in the thread take-up lever. The take-up lever is the part that will move up and down on the front of the machine.

2. The presser foot is down

After sewing thick fabrics or several layers, do not forget to lower the presser foot.

3. The upper thread has caught

Your upper thread will get caught somewhere that will happen if you leave a gap between the foam pad, thread spool, and spool disc. Use the foam disc underneath while you are using the vertical spool holder. The upper thread might break, so, raise the presser foot when rethreading, so that the upper thread is positioned in the tension disc again.

4. Do not use your knee-on-knee lever

I have seen sewers touch the knee lifter while they sew because they are sitting close to it. if you keep exerting pressure on the knee lever, the presser foot will be raised, which will cause the upper tension to become uneven. So, keep your knees away from the knee lever.

5. Switch off the secured stitches

You can switch off the secured stitches in the setup on newer sewing machines. Some sewing machines are set, so that, they make secured stitches when you sew. If you press the thread cutter button and start sewing, your machine will make securing stitches. If you are using thin fabrics, it will lead to the fabric and the upper thread pulling down right at the edge when you start sewing, which will cause a jumble of tangled thread.

6. When threading manually, pay attention to the sequence

You can thread the needle fully automatically. If you want to thread it manually, use a double needle or a thicker needle. Press the “Manual threading”, then press the “Automatic threader” button and thread into the needle manually. For some machines, you can remove the left cover of the machine by using the multi-function tool supply, it will let you see if the upper thread is really in the thread take-up lever.

Some More Tips If Your Machine Is Blocked

If the thread is pulled down inside, the machine is blocked and the details of the gear are appearing on the screen, you can follow the following:

  1. Do not pull the fabric or the threads, because pulling you cause sensitive parts, such as the thread cutter to damage.
  2. Remove the presser foot and the needle.
  3. Use scissors to cut the threads or the fabric above the stitch plate.
  4. Open the hook area and remove the bobbin case.
  5. Check if there are any tangled threads in the hook area.
  6. Release the blockage by turning the hand wheel forward.
  7. Remove the stitch plate and check if there are threads under the stitch plate.
  8. Try to renew the hook, bobbin case, bobbin, and stitch plate.
  9. Check if the upper thread has been threaded correctly.


What is bunching in sewing?

“Bunching” in sewing is often called “Birdnesting”, this is what it looks like when sewing machine thread bunches up on the top or the underside of your fabric. This is a very common problem when you are using a sewing machine.

How do I know if my bobbin tension is correct?

To check if the tension is correct, insert the bobbin in the bobbin case. Then hold it up by the thread, the bobbin case should not move. Try to move the thread, and if the bobbin case slides down slightly, then the tension is perfect. If it drops freely, then it’s too loose.

Why is my thread nesting underneath?

Bird nests occur when thread bunches up underneath the needle plate, it will cause broken threads, skipped stitches, and uneven tension. This is caused by the tension balance being out of whack or the top thread is not threaded correctly.

Final Thoughts

In this article, we have discussed, thread bunching is a very common problem, although, it can be fixed with some troubleshooting and adjustments. The main causes of thread bunching include improper thread tension, incorrect or damaged needle, improper threading, incorrect bobbin placement, etc. You can try to fix thread bunching, adjust the thread tension, check and replace the needle, rethread the machine, check the bobbin placement, and choose the right fabric for you. It will take some trial and error to find the right solution, but with little patience and persistence, you will get even stitches. If you are having trouble, try to seek assistance from a professional.


Hey I’m Sherry Howes an expert in sewing, knitting, crocheting, and embroidery. With a passion for fiber arts and a talent for crafting, I Have spent years improving my skills and sharing knowledge with others. Whether teaching a class or creating a new project, I’m always excited to share my love of crafting with the world. I like researching new techniques and trends in the crafting arts community.

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