Why Does My Bobbin Thread Keep Knotting Up

While sewing, you can have many problems, and it is frustrating because your sewing gets disturbed. One such problem is that your bobbin thread keeps knotting up.

Knotting occurs when your top thread and bottom thread are not properly contacted or do not interact correctly.

Whenever knotting happens, you will notice that thread will bunch underneath the fabric. It happens because the bobbin does not pull and jam thread correctly. As a result, a bunch of thread collects under your fabric.

Why Does Bobbin Thread Knot Up?

The knotting of thread may damage the fabric. So it is a must to identify the potential causes. Let’s figure out the reasons for the bobbin thread knotting up.

1. Wrong Bobbin Placement Can Cause Knotting

If you don’t set the bobbin and bobbin case properly, you could face such problems. Besides, you should also insert the bobbin thread correctly. If it doesn’t unwind correctly, the bobbin thread will not interact with the top thread correctly.

Sometimes, it also happens if the bobbin is not placed in the case correctly. If the threads do not interact correctly, they will not form the essential knots for the proper stitches. In the end, the thread will bunch up below the fabric.

If you don’t want these problems to occur, ensure that you correctly place the bobbin in the bobbin case.

Also, placing your bobbin case wrong can lead to knotting. That usually happens when you clean the bobbin area and then misplace it. So after each cleaning, be careful that you place everything in its position.

The thread should unwind the bobbin in a counter-clockwise direction to avoid knotting up.

2. Are You Using a Dull Needle?

The needle interacts with the top thread, makes a knot, and stitches the fabric. In this way, you create seams with the sewing machine. So if you are not using the correct needle, it will not catch the bobbin thread and get stuck up in the bobbin.

So you should avoid using blunt needles. If the needle is damaged, change it to a new one. Always use sharp needles for your sewing.

3. There Can Be Incorrect Threading

If the thread is not threaded correctly, it will knot-up. More specifically, you should focus on the top thread.

That’s because if the top thread is not correctly threaded, it might get stuck on the machine. As a result, the machine may not work smoothly, thereby creating tangles and knots.

Also, the top thread affects not only the machine but also the bobbin thread. Because of it, the bobbin thread would not be able to pull up into the fabric properly.

So it also affects the bobbin thread working. Thus, if this issue occurs, rethread the whole thread in the sewing machine.

4. There Might Be Bobbin Size Issues

If you are not using the correct size bobbin for your machine, the knotting issue will occur. The bobbin should not be too big or too small for your machine. Otherwise, the needle will collide with the bobbin and might break or bend.

Many sewers use multiple bobbins, so they do not have to change bobbins for every new sewing. You can get new bobbins at many sewing stores.

But, you must choose the right one for your machine. Choose the bobbins which are suitable for your specific sewing machine.

5. The Tension Isn’t Equal!

The most common reason for knotting and bunching of thread is the unequal tension of the thread. If the tension of the top thread and the bobbin thread are not equal, you will face knotting issues.

For a perfect tension, make sure that the top tension and the bobbin tension are equal. You can adjust the top thread tension by the tension dials available on the machine.

Likewise, use the bobbin case to adjust the bobbin thread tension. You can tighten or lose the thread by the screw present on the bobbin case.

So for avoiding knots, make sure that the tension is equal between both the threads.

6. The Tension Isn’t Suitable for Your Fabric!

If you set an equal tension of both threads, but still knots appear, then the tension might not be correct for your fabric.

In this case, try changing the tension according to the fabric you are using.

If you want to sew some thick woolen fabric, make the tension appropriate to this fabric type. Likewise, if you are sewing light or delicate fabrics, adjust the tension according to light fabric.

You may also need to get a new needle according to the fabric. Adjusting the correct tension will help you to avoid knots and tangles.

7. Thread Tails Might Be Too Short

The thread tails need to be long enough to avoid knots. Whenever you are threading your sewing machine, make sure that the thread tails are long enough.

They should be 5-6 inches or 15 centimeters to avoid knots. For that, you can hold the tails between your fingers at the time of the threading.

If they are too short, they will get pulled back. As a result, different types of knots will appear.

Both the top thread tail and the bobbin thread tail should be long enough. If both the tails are short, they will get pulled back in the machine, and then you’ll have to rethread the whole thread.

Can You Prevent Or Fix the Bobbin Thread Knotting Up Issue?

You may not always need professionals to solve these minor issues. Here is a list of doable solutions you can try in case your bobbin thread is knotting up.

1. Changing the Needle Can Prevent Half of the Problem

The thread might knot up because of the needle. Choose your needle according to the fabric you are sewing. If you are not using the correct needle suitable for your fabric, the thread will knot in many different ways.

Also, make sure that you are using a good, sharp, and pointed needle. The thread might knot up if the needle is blunt or broken.

So check your needle for better results. Make sure that you are not using an old needle for your sewing machine. To prevent your needle from bending, correctly use the machine.

2. Thread the Machine Correctly

To avoid knots, make sure that you have threaded the machine properly. You can always use your sewing machine manual to ensure proper threading.

Thread the upper thread correctly. It should pass through all the thread guides properly till it passes through the needle.

Make sure that whenever you are threading the machine, the presser foot is up. If the presser foot is up, the thread will sit properly.

Likewise, if the presser foot is down, it will not allow the thread to sit correctly. Besides, the machine will fail to establish an equal thread tension.

If the thread doesn’t sit correctly through the tension discs, proper tension won’t establish on the thread. After that, some defects in the stitches may occur. So correct threading of the thread is obligatory.

3. Ensure Correct Bobbin Placement

Check that the bobbin is inserted in the bobbin case correctly. For inserting the bobbin into the bobbin case correctly, you can use the manual provided with your specific sewing machine or else check online manuals according to your sewing machine model.

Also, make sure to achieve correct threading into the bobbin. The thread should be even, smooth, and knot-free.

4. Cleaning the Machine Is a Mandatory Task

At last, if the knotting problem is still not solved, clean the machine properly. There should not be any dust particles present in any machine parts, especially in the bobbin and bobbin case areas.

So clean the machine and do proper oiling of the machine to avoid knotting up the thread.

That’s it! Now, your bobbin thread will no longer knot up. Follow the above instructions to both prevent and solve this minor issue. These tricks don’t need special skills or expensive tools.

What Does Bobbin Thread Knotting Up Mean?

Knotting means that the top thread and the bobbin thread are not cooperating correctly.

Whenever the thread experiences knotting, large loops and knots appear on the backside of the fabric. Usually, knotting appears beneath the fabric.

Above all, it also occurs because the bobbin continually draws and blocks the thread. In the end, there will be a bunch of thread beneath the fabric.

Can I Fix the Bobbin Thread Knotting Up Issue at Home?

Yes, you can fix the bobbin thread knotting up or related issues at home. First of all, make sure you keep the machine clean and oil it at regular intervals. Besides, you should also look after the thread tension and make it correct according to your fabric and machine.

Even so, you can also work on preventing this issue. For this, make sure you thread the machine correctly. Moreover, use the correct and sharp needle suitable for your fabric.

If you still experience the knotting issue, follow the instructions given in your sewing machine manual.



I'm Jessica Flores, a professional fashion designer and an expert seamstress. Crafting has always been a deep-seated passion of mine, one that has flourished and evolved over the years. I've dedicated considerable time to both studying and practicing in the realm of fashion and sewing, amassing a wealth of experience and skills. It brings me great joy to share these insights and experiences with you all, hoping to inspire and foster a similar passion for the art of sewing.

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