How to Fix Bobbin Tension

April 23, 2020

Is your bobbin thread showing on the top side of your fabric? Are your stitches just looking wonky and not very strong or even? Sounds like your sewing machine tension is out of whack or your bobbin is behaving badly! Let’s talk about how to check to see if it is AND how to fix bobbin tension on your sewing machine. If you need to thread your machine and fill you bobbin but do not know how, first check out this post about threading almost any kind of sewing machine.

This post is for the beginner who is somewhat comfortable with their machine and has been working along for a little bit without issue. You will learn how to check and fix bobbin tension if you are having stitch formation issues. *The machines we are working with today have a bobbin case for their bobbins. The process of fixing tension is relatively similar for drop in/top loading bobbon style machines (like Brother, BabyLock, Janome brands). Look further down where the is and you’ll see more machine specific bobbin information there.


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up close photo of a sewing machine bobbin case

When stitches become weak, bobbin threads show on the top or thread bunches keep happening, getting to know more about the machine will help solve the problem. Since stitch formation is a relationship between the upper thread from the spool and the bobbin thread coming from the bobbin, both the upper thread and bobbin tension need to be looked at to solve problems.

Tension describes the amount of pull on the thread and correlates to the tightness of your stitches. Too much tension, the thread ends are pulled to far apart and the thread might snap. Too little tension, the thread will sag or not lay flat on the fabric because there is too much slack.

In this post, we are going to focus on the bobbin tension. Upper thread tension is easier to change, there is a little moveable dial on the upper left portion of the machine, along the path the thread takes from the spool to the needle. There are numbers on the dial, making it easier to make note of your upper thread tension. Adjusting the upper thread tension is one of the first places to look when trying to solve tension issues. I’m focusing on bobbin tension first because there is less information out there about it, we can delve into upper thread tension at a later date.

Do you have the correct bobbin for your machine?

Please make sure you have the correct bobbins for your machine. You can find universal bobbins at most large craft stores buy they are not truly universal!!!!!

If you need to find more bobbins for your machine, start here with these links. I’m listing some of the most common brands and the most common styles of bobbins. This list is here for your convenience, but you need to check the list of machines before purchasing. I don’t know all the product numbers of all the sewing machines out there, you will need to find the exact model in order to find the correct ones. Don’t hold me responsible for wrong size bobbins! I’m innocent!

Bernina Bobbins from Amazon – Check the list of machines before purchasing. Not all Berninas take the same bobbin.

Brother Bobbins from Amazon – There seems to be a few different styles for different ages of machines.

Featherweight (by Singer) Bobbins from Amazon – Make sure you don’t get generic Singer Bobbins they won’t work.

Husqvarna/Viking Bobbins from Amazon – They’re green! I didn’t know that…

Janome Bobbins from Amazon – Top loading bobbins, a bit wider than other brands.

Juki Bobbins from Amazon – Lesser known brand but super sturdy reputation.

Singer Bobbins from Amazon – These are probably the most common variety and easiest to find.

What Good Thread Tension Behaves Like:

The relationship between the upper thread and the bobbin thread will affect the quality and strength of the stitches your machine makes. In a well formed stitch, the threads meet together in the middle of the fabric and lock together evenly. You should not see your bobbin thread on the top of your project and you should not see the upper thread on the underside of your project.

When the bobbin thread is not tensioned properly, it will show in how the two threads appear on the fabric. You’ll likely find out that your tension is off by looking at a section of stitching that doesn’t look like how you were expecting it to. Maybe the bobbin thread is showing on the top or the upper thread is so loose it pulls out easily. Sometimes it’s on your nice, expensive project fabric! Let’s get the bobbin tension checked and fixed before it happens on your next project. 

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Horizontal vs. Vertical Bobbin Cases:

Some machines, such as Singer and Bernina brands have their bobbins in cases within a bobbin race that holds the bobbin case in an upright, vertical position. The bobbin case needs to be removed in order to change to a new bobbin.

The inside of a sewing machine, bobbin case
The inside of my Bernina showing the bobbin race and case, as viewed from the front of the machine.

◉ Others, such as Brother and Janome brands have the bobbin laying horizontally, partially under the throat plate of the machine, usually not in traditional bobbin case but in a differently shaped bobbin case that stays in the machine most of the time. You can tell the difference between the machines not only by bobbin location, but also how the bobbin case does not need to be removed to change the bobbin.

Bobbin holder from Janome Sewing Machine
Bobbin case on a Janome, we’ll learn more below.

Check Bobbin Tension (so you can fix it later)

This first part is for machines that have a bobbin case that comes out of the machine in order to change the bobbin. For machines that you just drop the bobbin in, see ◉ below.

To start, pull out the bobbin case from your machine. You can pull on that little handle on the front of the case and it will pop out the machine. Gently drop out the bobbin and load in a freshly wound bobbin, following the directions in your sewing machine manual. A properly wound bobbin is also important to get good tension.

Do not put the thread through that extra little arm or coil sticking out (if you have one, mine does). That is used for any embroidery modules/ functions on your machine, it will interfere with the bobbin test and you will not get accurate results.

Next, place your index finger and thumb where the thread comes out of the case and pinch the thread. Holding your bobbin case about a foot over a soft surface in case it drops, flick your wrist in a downward motion so that the case moves down with you still holding the bobbin thread. The motion reminds me of playing with a yo-yo.

One of four things can happen:

1) Your bobbin falls out of the case and hits the soft surface. This doesn’t help us test tension or mean anything, it just happens when you start trying out this technique. Start over, it happens to everyone, including me, a LOT!

2) Your bobbin goes nowhere… Your fingers are still pinching the thread at the point where the thread comes out of the case. This means your tension is TOO TIGHT. Your bobbin thread cannot leave the case and this will not allow the bobbin thread to meet in the middle of the fabric with the upper thread.

3) Your bobbin falls down, almost to that soft surface you held it over. This means your tension is TOO LOOSE. The thread is just coming out way too fast and will bring your bobbin thread to the top of your fabric, where it does not belong!

4) Your bobbin falls only an inch or two below the point you have the thread pinched. This is GOOD TENSION! You want the bobbin case to hold onto the thread enough to catch its fall, but not so hard that it doesn’t move anywhere or fall more than those two inches.

This movement takes practice. I feel like a wizard waving a wand trying to perfect the wrist action. Swish and Flick. Anyone?

If anyone asks what you’re doing, just tell them the truth or tell them to bugger off! (That doesn’t sound too kind does it? I think I just like using the word ‘bugger’.) Or you could just tell them that you found a quick way to check and fix your bobbin tension…

To see this in action, here is a video:

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How to Fix Bobbin Tension ✅

Now that we understand how to check bobbin tension, let’s take a look at how to fix bobbin tension. Figure out if your tension is too loose or too tight. Then, following the instructions below, fix it!

On the bobbin case you will notice a very small, flat head screw. There may be other screws, but they will likely be Phillips head screws that are super tiny. Take a small screwdriver that will fit into the slot on the screw. After testing your bobbin, you should be able to determine if your bobbin tension is too tight or too loose.

Bobbin case tension adjustment screw
Close up of the flat head screw that adjusts the tension on the bobbin thread.

To tighten bobbin tension, turn the screw clockwise/to the right (‘righty tighty’) in very small increments. 1/8 to 1/4 of a turn (imagine a circle that is the head of the screw, only turn it 1/8 to 1/4 of the circle at a time).

Test the tension between each adjustment of the screw.

To loosen bobbin tension, turn the screw counterclockwise/to the left (‘lefty loosey’) in very small increments. 1/8 to 1/4 of a turn (imagine a circle that is the head of the screw, only turn it 1/8 to 1/4 of the circle at a time).

Turning the flat head screw makes the plate that it is attached to go closer or further away from the rest of the bobbin case. The bobbin thread travels between the plate and the case, so by adjusting the plate, you are adjusting the tension on the thread. Tension in this situation is really about the speed at which the thread comes out of the bobbin. Too slow and you’ll get a really tight bobbin thread, too fast and you’ll see the bobbin thread on top of the fabric. Both Bad!!!

Bobbin case from Bernina Sewing Machine
What the Bernina bobbin looks like out of the machine. Most bobbin cases look like this, even for other types of machines like commercial embroidery machines.

If you find that you have gone too far in one direction, just gently go back in even smaller increments. Keep testing until you like how the stitches are formed. After adjusting the tension, don’t touch the screw and be careful not to drop the case.

What does Thread Thickness have to Do with it?

Hold the bobbin up to your face so you can see between the bobbin case and the tensioning plate clearly. When very fine thread is used in the bobbin, we need that plate to be closer to the bobbin case so that the plate makes contact with the thread and holds it tightly enough to tension it properly.

If we place thick thread in that bobbin for the next project without accounting for the thickness of the thread, what do you think will happen? The thread will not be able to slide freely, it will be too thick to fit in between the plate and case. That will result in the bobbin thread not forming stitches correctly with the top thread. It may cause the fabric to pucker, it might break from all that tension or it might only mess up your line of stitches. None of which we want to happen, because all of these results will make our project look not so hot.

Don’t forget the opposite situation, what would happen using a thick thread first then a fine thread for the next project? That thin thread would be sliding through so fast with nothing to keep it in place. It will cause very loose stitches, very uneven stitches or a thread bunch.

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◉ For Drop in Bobbin Style Machines

For drop in bobbin style machines, testing is a little more hit or miss. First, make sure your machine is threaded properly. Then take a look at your upper thread tension dial. Looks something like this:

Upper thread tension dial on a sewing machine
The magic place to begin testing tension on a machine with a drop in bobbin. Also where you adjust the upper thread tension.

The upper thread tension dial should have a special mark next to one of the numbers. That mark is a good place to start testing out your bobbin tension, it is sort of the default setting for the upper thread tension.

In order to take the bobbin case out, you need to remove the throat plate. There are usually somewhat large flat head screws holding it down. They should be the only screws showing on the plate. Pardon the little focus issue, but that screw on the right is what the screws look like on the throat plate of the Janome machine.

Sewing machine throat plate
See that screw on the upper right corner? That is one that needs to be removed to take off the throat plate.

Showing the image below again so you see where the tension adjustment screw is when the bobbin case is still in the machine. You need to take the case out to adjust the tension, please don’t go sticking screwdrivers into your machine at random, especially if it is still plugged in!!!!

Bobbin holder from Janome Sewing Machine
Bobbin case on a Janome, visible after removing the throat plate.

Take a scrap piece of fabric and start sewing with a straight stitch or whatever stitch you were using when you discovered the problem. How do the stitches look? If the bobbin thread is too loose and showing on the top of the fabric, carefully tighten the flat head screw (shown below) to the right. If it is too tight and the upper thread is being pulled to the back of the fabric, loosen the screw by turning to the left. Remember, righty tighty – lefty loosey? It works here too.

Bobbin case from a Janome sewing machine
The bobbin case, removed from a Janome. This is a drop-in style bobbin case.

Keep adjusting that flat head screw in the proper direction until you have a balanced stitch that doesn’t show thread on the wrong side. Ignore the Phillips head screw, it doesn’t get touched for the tension.

Test, test, test, test, test!!!!

The only way to see if you have been successful on both types of machines is to TEST. Don’t forget to test out your tension between adjustments on scrap fabric – more specifically the same thread and same kind of fabric that you are using in your project!

AND if for some reason the bobbin tension just isn’t improving, get the top thread tension involved, they need to work as a team to let you sew nice seams.

How do you show your sewing machine some love?

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Want to remember this? Post this How to Fix Bobbin Thread Tension Tutorial to your favorite Pinterest board!

Bobbin on purple fabric

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  • Reply erin manion January 28, 2024 at 4:11 pm

    what Happens if the Phillips head screw on a drop in bobbin case is turned and how do you fix it?

    • Reply Marissa January 29, 2024 at 12:21 pm

      Hi Erin,
      Help me understand your question, is the screw turned too tight or loose? I am not understanding how the screw is “turned”… Thanks!

  • Reply Sheila January 23, 2024 at 9:20 am

    I look at your stitch clinic but I do not see any instructions on how to adjust the bobbin tension.

  • Reply Vikki Fordham February 8, 2023 at 12:56 pm

    Marissa, I have a 50 year old Singer sewing machine. I am trying to get the tension right. When I sew a test, the top and bobbin stitches look fine, but if I pull on the bobbin stitch it will pull out. Is this normal, or what is wrong?

    • Reply Marissa February 8, 2023 at 5:00 pm

      Hi Vikki, It sounds like either a needle or timing problem where the upper thread isn’t catching the bobbin thread. Is this a very thick fabric you’re working with? Normally when the upper thread and bobbin thread aren’t catching the stitches don’t form, but I can imagine if it is a very dense or thick fabric it might be holding onto the thread just enough for you to think the stitches/tensions are correct. I have a thread bunching solution guide you can get for free. It is on the same page where you submitted this comment. Get it and go through all the steps to see if anything there works. If it is a timing issue – timing is the movement of the needle in relation to the bobbin, the bobbin race (holds the bobbin case) spins and when the needle dips down into the machine, it should line up with the bobbin thread to catch it and form the stitch. Timing issues are normally left to sewing machine repair professionals. Do you have the manual? I would start with the thread bunching solution guide first, then if that doesn’t take care of it, contact a local sewing repair shop. The free solution guide can be found here: just scroll down a little bit and click on the ‘notebook’ cover that says “Thread Bunchins Solution Guide”. Fill in the info and it will be automatically sent to your email. Thanks for reaching out, let me know how it goes!! – Marissa

      • Reply Laura Ward April 2, 2023 at 3:17 pm

        I only sew straight lines, like for mending. The top thread looks fine, but the bottom thread I’d loose and bunches up? I’d send a picture if I could. how do I fix this

        • Reply Marissa April 5, 2023 at 11:03 am

          Hi Laura! Did you download the free Thread Bunching Solution guide? If not, start there and go through the steps. If it is still not working do feel free to reach out! You can send me a photo to so I can take a look.Thanks!

  • Reply Deborah Devine June 7, 2022 at 7:04 am

    just fyi – I have had two sets of “counterfeit” Bernina bobbins from online dealers including Amazon. One set was obvious because the diamond pattern etched on the shaft of the bobbin was uneven in both pattern and depth, but another set was weighted incorrectly and it took a Bernina dealer/repair person to diagnosis the issue. Now I only get bobbins from a reputable quilting store or a Bernina dealer, never from Amazon or other online dealers.

    • Reply Marissa June 8, 2022 at 4:23 pm

      Hi Deborah! Oh my goodness, sorry you had that problem with the knock off bobbin cases. I’ve ordered some from amazon too but did not have any issues. I think that it’s important to read the listings so carefully. I do recommend some amazon items, mostly because not everyone lives near a dealer or even know they exist and some don’t have online shops. I have friends who only buy off amazon for the convenience 😬 Cheers and thank you for sharing your experience, love feedback for anything sewing.

  • Reply Kim May 17, 2022 at 10:23 am

    Hello! I am struggling to get the top and bottom tensions adjusted for some top sticking I want to do. The top fabric is a slightly heavier polyester fabric and the lining is a lighter weight 100% cotton. I want to use two different color threads. The top navy blue thread is a little thicker than the bobbin light yellow thread. When I do a test stitch, I can see both colors on both sides. The tension on the stitches looks good — no puckers or loopy threads. It’s just that I can see little “dots” along the tracks on both sides. I have an old, Singer 237 from 1965 (!!!) and everything is manually adjusted. I am starting with the tension on the upper thread at “4” and the bobbin thread at “4” on a scale of 1-8. Any advice? Thank you! – Kim

    • Reply Marissa May 17, 2022 at 1:08 pm

      Hi Kim! You are actually getting the right tension! You are supposed to shoot for the thread to rest in the ‘middle’ of the fabrics when looking at it from the edge of the fabrics at the seam – have to visualize it. I think they reason you are seeing it is the contrast of the thread color? Those little dots are the opposite thread catching. The top thread is caught by the bobbin thread to keep the stitch together, it is a little twist and this is why you are seeing the bobbin thread on the top and vice versa. I hope you understand what I mean. If not, reach out to me and I can show you a drawing of what I mean.

  • Reply Hez April 26, 2022 at 10:48 pm

    Thanks. I’ll give it a try. I have a Janine drop in bobbin. Perhaps my machine might also need a service. 🤔

    • Reply Marissa April 26, 2022 at 11:38 pm

      Let me know if it works and thank you for checking out Stitch Clinic!

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