Why Is My Bobbin Thread Loose

Your sewing machine relies on the bobbin and top thread for effective sewing. You can’t sew anything when either of these two is defective. A loose bobbin thread causes your threads to bunch, stitches to skip, and sewing machine needles to break.

There are many reasons why your bobbin thread may be loose. Troubleshoot your loose bobbin problems gradually until you get the solution. Solving the problem correctly ensures that your sewing machine remains in good condition. 

Why Does Bobbin Thread Become Loose?

One of the major causes for your bobbin thread being loose is that your sewing machine or bobbin is not properly threaded. To solve this problem, you need to take your bobbin out and check that it is properly threaded. Then confirm that the top thread is also properly threaded. Then rethread your top and bobbin thread. Then place your bobbin in its case as it should and start sewing. Confirm that your bobbin thread is now working properly as both the top and bottom stitches on the fabric you are sewing form properly.

1. Your Sewing Machine Is Not Properly Threaded

One major reason why your bobbin thread is loose is that your sewing machine is not threaded properly. To properly thread your sewing machine, you need to thread your bobbin and your top thread correctly. 

To correct this, you will need to rethread your sewing machine. Start by threading your bobbin. Remove the thread on the bobbin. Then place it on the bobbin spindle at the top of your sewing machine. Also, load a spool of thread. 

Pull your thread and loop it through the guide and insert it into the bobbin and roll some thread on it. Then push the bobbin spindle to the left, press the foot pedal and the thread starts loading the bobbin. When it’s full, stop the process and insert the bobbin in its case properly.

Then, rethread the top of your sewing machine. Follow the guides on your sewing machine to properly thread it. If you are a sewing beginner, you can easily refer to the user manual for the best instructions on how to thread a sewing machine.

Start sewing to confirm that the bobbin thread is not loose anymore. 

2. Your Bobbin Is Not Properly Placed In The Bobbin Case

Another cause for your bobbin thread being loose is that your bobbin is not fitted properly in the bobbin case. One of the reasons for this could be that you placed your bobbin in the case in the wrong direction. Check this and rectify it to get your bobbin thread working correctly.

You could also be using the wrong bobbin for your sewing machine. Every sewing machine has a specific bobbin associated with it. If your sewing machine is designed to use a plastic bobbin if you interchange it with a same-size metallic bobbin, you will have a problem with your bobbin.  

Check your user manual for the appropriate bobbin for your sewing machine. You can then order it from your manufacturer or any sewing supplies shop. 

3. Your Bobbin May Be Cracked

Another reason why your bobbin thread is loose is that your bobbin or bobbin case may be cracked. This prevents the smooth movement of your bobbin thread from the bobbin to the needle.

The crack on the bobbin case holds back the bobbin thread as it moves from the bobbin to the needle during sewing. This causes a lag on the thread causing the bottom stitches to bunch up or be loose.

Confirm that there is a crack on your bobbin. Then replace the bobbin with a new one. Thread it properly and place it back in the sewing machine and continue sewing.

4. Bobbin Tension

Your bobbin tension may also cause your bobbin thread to loosen. If the tension in your bobbin is low, the bobbin thread will be loose.

How can you tell when your bobbin tension is loose? Take the bobbin and bobbin case out of the sewing machine. Hold the end off the bobbin thread with your hand raised. Then pull the thread upwards. If the tension is right, the thread should release slightly and the bobbin case should drop an inch only.

However, if the bobbin tension is loose, your bobbin thread will come undone and your bobbin case will fall to the floor. If the bobbin case remains in place, the bobbin tension is too tight.

To rectify a loose bobbin tension, find a screw in the bobbin case. Then turn it clockwise. If the bobbin tension is too tight, turn the screw anticlockwise.

With the bobbin and sewing machine at the correct tension, you will not have loose bobbin thread problems. Regularly check the bobbin tension of your sewing machine.

5. You May Be Using The Wrong Needle And Thread For The Fabric Sewn

A major cause for loose bobbin thread is when you use the wrong needle and thread for the fabric you are working on.

Different fabrics are best sewn with needles and thread suitable for the fabrics. If you work on a fabric with the wrong thread, the needle and bobbin timing will clash. This will cause the bobbin thread to be loose.

If you are working on a hard fabric, you need a suitable needle and thread for the fabric. You need a strong needle and a strong thread to ensure that your sewing machine sews appropriately. When you use the wrong needle and thread with slippery fabrics, your bobbin stitches will skip and those that connect will be loose.

6. Poor Quality Thread

Similar to using the wrong thread and needle on a piece of fabric, using poor-quality thread may cause your bobbin thread to be loose. Especially if you are using a poor-quality thread in your bobbin.

Always find out what kind of thread your garment requires before you start sewing. Don’t use the same thread for every project that you work on.

7. Your Sewing Machine May Be Broken

If your sewing machine is broken, your bobbin stitches may be loose. Sewing machines need regular servicing. Clean your machine the more you work. This helps you to see the different parts of the machine and take care of them properly.

If you don’t lubricate the moving parts of your sewing machine, it is likely to break down. When parts of the sewing machine are not moving correctly, it is likely to cause a loose bobbin thread.

Regularly clean the bobbin case of lint and other types of dirt from fabrics, thread, and oil. This will ensure that it works as effectively as it should.

How To Load A Bobbin Into A Sewing Machine?

There are two types of bobbins depending on how they are loaded into a sewing machine. A front-loading bobbin and a top-load bobbin.

To load a front-loading bobbin, switch off your sewing machine and unplug it from any power source. Then lift the needle to its highest position. Fit your wound bobbin into its bobbin case and hold the bobbin case lever and press it onto the pin. When you hear your bobbin click into place, close the bobbin case and start sewing. Make sure to leave at least three inches of thread from the bobbin.

To load a top load bobbin, switch off the sewing machine. With the needle raised remove the bobbin cover plate. Wind your bobbin then put it in the bobbin case and twist in the direction as directed on your user manual. Fix your bobbin in place, and replace your cover plate.

To load any type of bobbin properly, you need to know all the parts of the sewing machine. This makes it easy to not only load your bobbin but also to troubleshoot any problem that occurs on your sewing machine. Learn how to load your bobbin properly for an enjoyable sewing time.

Are Bobbins Interchangeable?

There are two types of bobbins that you can use on a sewing machine. A metallic and a plastic bobbin. Different sewing machines use different sizes of bobbins. Each sewing machine manufacturer also has different bobbins for all their brands of sewing machines. Thus, there are hundreds of bobbins you can find in a craft shop.

However, when it comes to buying a bobbin, you need to know the specific size and type of bobbin your sewing machine uses.

If your sewing machine uses a metal bobbin, you cannot use a plastic bobbin. To be sure about the bobbin size you want for your sewing machine, you need to confirm with your user manual or manufacturer’s website.

Buy your bobbins from the manufacturer or from an expert in the sewing supplies shop. Here, you will get the best advice you need on the best bobbin for your sewing machine. 

Using the wrong bobbin on your sewing machine can be problematic. It will make your bobbin thread loose and even make your threads bunch up and your sewing machine jam.



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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