Last Updated on 8 months by Susan Mayrich
Are you wondering what is a bobbin on a sewing machine? A bobbin is a spool or thread cylinder used in sewing machines.

The thread wraps around the center post and gets stretched out by the needle. As you sew, it feeds off the top of the bobbin and through your fabric to make stitches.
A bobbin on a sewing machine is a spool or cylinder that holds thread for your sewing machine. When you sew, the needle passes through both fabric layers and hooks onto the bobbin thread as it goes back up to make a stitch.
If you notice your stitches are too loose or too tight, this could be because of an issue with the tension on the bobbin.
What A Bobbin Is On Your Sewing Machine?
So, what is a bobbin? Bobbins are usually made from plastic and come in many different sizes depending on the weight of the sewn fabric. They used to be made of metal, but they are now mostly plastic. Regardless, you should always follow the manufacturer’s instructions handbook with your device to determine how it should be used since every machine is different.

What Are Bobbins Used For?
Bobbins are mainly used for holding threads on a sewing machine. The thread wraps around the central post and is fed off by the needle. Bobbin thread is unwound from the bobbin, passes through the needle eye, then over a tension system that tightens or loosens it to keep stitches at an even, consistent length. This saves time because you don’t have to stop using a spool of thread every few inches.
Where Is It?
The bobbin is inserted into a compartment at the bottom of the machine known as the bobbin case. The thread will emerge from a small hole that opens up when you close the case. A bobbin can be inserted into an empty spool or attached at one end by winding it around the shaft of an empty spool with a special attachment called a “bobbin winder” before tightening it down with pliers.
What A Bobbin Is For Knitting?
A bobbin for knitting is a small cylinder that holds the yarn in place while knitting. It makes it easier to change colors or add new yarn without knot or tie new pieces on. You can also use a bobbin of thread instead of a spool if you prefer that over a ball of yarn.
A bobbin is typically a small, round spool of wire used as a coil to hold thread on wind-up style sewing machines. Standard bobbins aren’t large enough to fit bulky threads or strands of yarn, so they are usually reserved for more delicate materials and single-color projects.
Essential Parts Of A Sewing Machine Bobbin
The following are parts of the bobbin on a sewing machine.
Bobbin tension
The bobbin tension is the most crucial factor to consider with sewing machine bobbins because it affects the quality of the stitch. The bobbin thread’s tension decides how tight or loses your stitches are.
Depending on the material you are sewing, three different types of bobbin tensions are used: lightweight materials require a lower tension, medium-weight materials require an average tension, and heavyweight materials require a high tension.
Because there will be too much give in the thread due to a low bobbin tension, it will stop feeding through after numerous stitches have been created, resulting in loose threads. A high bobbin tension results in tight stitch seams, but it’s also prone to tangling threads since there is too much give.
Bobbins have their tension mechanism. You won’t have to touch this area if you’re a novice sewer. All you need to know right now is that the bobbin tension may be reset to your preference. It’s best to leave the bobbin tension at its factory setting until you have sufficient expertise to adjust it.
Bobbin winder
A bobbin winder is a small tool to put thread over the spool of the bobbin to make it ready for your sewing machine. It can be tricky, so take care when using one. It’s also necessary to wind bobbins correctly to avoid damaging them or committing any mistakes that might mess up your sewing project.
The central core should be wound in the same direction as the threads coming off the coil’s side. Otherwise, you’ll have knots in your bobbin and jammed-up threading on your sewing machine. Loading a thread ensures that the thread pool is sent straight to the bobbin without interruption.
A bobbin should be wound evenly, much like a thread spool. There should be no tangles or knots, and neither end of the line should be thicker than the other.
Bobbin case
The bobbin case is the area that holds the bobbin on a sewing machine. The bobbin case can also be referred to as a bottom box or as a lower compartment. Threading the bobbin is not as easy as it may seem, and specific steps must be followed to do it properly.
How To Wind A Bobbin?
Winding the bobbin shouldn’t be difficult if you know what you’re doing. Before I go through the steps for winding a bobbin, it’s vital to remember that you should always wind your bobbin before threading your needle and machine.
#1. Insert the bobbin into the sewing machine, making sure to put it incorrectly so that the thread will come out from a hole at the bottom of the case
#2. Wind your thread around a spool or winder for as long as you want it to be
#3. Put on your safety glasses and use pliers to tighten down on one end of the coil with a firm grip
#4. Adjust tension according to what type of material you’re going to sew; lightweight materials require a lower tension, medium-weight materials require an average tension, and heavyweight materials require a high tension
#5. Remove any knots by pulling them apart gently with your fingers before they can cause damage or jam up your sewing machine’s threading
#6. After you have adjusted your bobbin tension to the correct setting, insert the bobbin into the case with thread coming out of the hole on top of the case. Then place your fabric under the presser foot and hold up on the needle, so it’s not touching anything
#7. While lifting the presser foot, turn the hand wheel until the needle is at the highest point, and then lower the presser foot
#8. Lowering the presser foot will cause the needle to push down on the thread, causing the thread to be wound around the bobbin. Once you reach this point, raise your presser foot and reposition your fabric under the foot before lowering it again
#9. Repeat step 8 until you have no bobbin thread left
#10. If the top thread seems to be loose with extra slack, use your tightening knob to adjust the tension of the top thread until it has less slack
#11. Once you are sewed, make sure you tie off the end knot of both threads together before cutting the top thread because if not, it will get wrapped around your bobbin case and mess up the threading of the sewing machine.
Insert the bobbin into the case with thread coming out of the hole on top of the case. Then place your fabric under the presser foot and hold up on the needle, so it’s not touching anything. Lowering the presser foot will cause the needle to push down on the thread, causing the thread to be wound around the bobbin. Once you reach this point, raise your presser foot and reposition your fabric under the foot before lowering it again. Raising the presser foot will cause the bobbin case to rotate one full turn, taking up all of your newly wound bobbin thread.
How To Insert A Bobbin?
Inserting a bobbin into the sewing machine correctly is an essential step in any sewing project. There are many different types of bobbins, and choosing one that matches your type of fabric is essential. This ensures that you’ll be able to sew easily without damaging the material or getting caught up in knots.
Bobbins can be wound either clockwise or counterclockwise, depending on how they were inserted when manufactured. If you insert them clockwise, then wind them counterclockwise, they will come out much more smoothly than if you wind them the opposite way around because this will cause less tension to build up inside the case due to friction between threads.
The two most common types are plastic bobbins and metal bobbins. Metal bobbins are generally smoother but take up more space in the bobbin case than plastic ones due to the thread not wrapping around them evenly.
Special plastic bobbins like the Schmetz brand also feature an indentation for your thumb to grasp when quickly removing them from the case. Here is a video tutorial on how to insert a bobbin:
What A Bobbin Is- Troubleshooting
The following are some possible causes of malfunctioning bobbins:
- Too much tension on the bobbin thread
- Bobbin thread is worn out or unraveling
- Thread not threaded through or twisted on top of the bobbin
- Bobbin winder slipping
- Pins in the way of needle and upper looper; remove them; loosen upper tension; rethread and test
- Thread tension too loose
- Bobbin case threaded incorrectly, and thread is preventing bobbin from turning correctly.
THE HINT: Most problems can be resolved by rethreading the bobbins and their respective cases, making sure everything is in its proper place. We recommend using a magnetic screwdriver for this purpose.
Frequently Asked Questions (FAQs)
Here are the answers to your questions:
Do you need to use a bobbin in sewing?
Yes, The thread is brought up from the bottom of the fabric where it wraps around a bobbin. The bobbin gets wound by the machine, which will cause tension on your top thread. This helps to give your project stability, shape, and fullness even if you do not leave any spots undone.
If you are using a serger for overlocking seams, you need to use a specific type of case that can hold both needles. These cases come in various sizes with plastic or metal components to choose from, depending on the size of needles used for this process.
You also have options when it comes to how many bobbins are needed for these machines typically include anywhere from one slot to four slots for bobbins at once
Do all sewing machines have a bobbin?
Yes, all sewing machines require a bobbin. The majority of sewing machines come with 3-5 bobbins in the box. Many people believe that is plenty of bobbins when they are just getting started, but we see them back within a few days looking for a few more.
How do you put the thread on a bobbin?
When should I use bobbin thread?
One would use bobbin thread when sewing fabrics like silk, lace, and chiffon.
What is the point of bobbin thread?
Bobbin thread is a thin, fine strand of yarn or cotton thread wound around a bobbin. It is used as the second loop on top of the spool of sewing machine threaded. The bobbin’s job is to carry and provide consistent tension for this single layer of fabric as it moves under the needle.
How do I know what bobbin I need?
What is the difference between a 15 and a 15J bobbin?
A 15J bobbin is for decorative stitching. A 15 will have a cotton thread on it, which is what you would use for regular sewing. Bobbins for standard home sewing machines are virtually identical, except that class 15 bobbins have flat ends and class 15J bobbins have somewhat curved ones.
They may seem to work interchangeably at times, but even if they fit into your machine, there is a danger of causing serious damage by jamming it up.
Does the bobbin color matter?
The bobbin color does not matter. You can use whatever color you want.
What are the benefits of bobbin thread?
Bobbin thread is thin, so it can easily go through tight curves. It also has a core that carries the tension well, which is important for damaging the thread.
What is the difference between a bobbin and a spool?
A bobbin is a spool-like container threaded with a continuous length of textile thread and used in needlework such as sewing, quilting, embroidery, and crochet.
The thread unwinds from the spool through the hole in the center of the top of the work or sits on a hollowed-out pine cone at one end with a “spur” running up one side to keep it from unwinding too far. A spool typically has no wire core inside.
Every time you pick up your bead project, make sure to put your previously used bobbin back away from your workspace before getting started–so if you need to stop for any reason and pick it back up first thing next, go round. You may also be interested to know about common sewing machine bobbin problems.
It’s A Wrap!
Now, you’ve known what is a bobbin on a sewing machine? You may also want to read about Singer sewing machine not picking up bobbin thread and Singer sewing machine bobbin winding problems.