Sewing Machine Tension Numbers

Determining the accurate sewing machine tension numbers is never stressful if you know what to look for. Listed below are some of the essential truths of thread tension dials setting and adjustment. 

Speaking of tension dials, don’t you know that a number of dressmakers dodge it? I bet that you know why. This is because tension dials can mess your seaming machine up whenever adjustments have gone wrong. It is good to know that regardless of a sewing machine’s model and make; there is no secret in thread tensions setting. It is confusing, yes. A misadjusted tension dial has a huge potential to make the entire process more baffling. In most cases, problems that are associated with tensions are caused by incorrect tension dials adjustment.

If you think that your machine’s tensions are balanced and that they need no adjustment, you better think again. Thinking such a way is wrong. Balanced tensions need to be adjusted regularly. Too tight sewing machine tensions may break the seams easily when overextended. To test, you can stretch it over on a 6-inch cross-grain seam (at least). On the contrary, too loose tensions expose the threads in-between gaps or sections, to the extent that the gaps are made open when pressed.

Understanding The Numbers on The Thread Tension Dial

Tension is one of the most important aspects of sewing, but it’s also one of the most misunderstood. There are a lot of factors that can affect tension, from the type of fabric you’re using to the type of thread.

Sewing Machine Tension Numbers Chart

The rule of the thumb says that, when stitching, all guides must be threaded beforehand. Speaking of guides, threads are properly guided along its accurate path. Thus, every thread guide shows little resistance to the thread, which, in turn, adds tension to the machine’s discs. As a result, a balanced tension is achieved.

The flat bobbin-case springs also put on pressure to the thread the moment it moves out from the case. That tiny screw located at the back of the spring regulates the pressure. The aforementioned screw and spring can be located easily each time you remove the bobbin case.  

For machines that have a built-in bobbin case and a drop-in bobbin, expect to have a hard time finding the tension screw. Most home machines are setup this way in addition to some consumer long arm quilting machines. The illustration above shows both types. In detail, it is important to know that in order to improve the resistance, you may simply hit the screw clockwise (if you want to adjust it to a higher number) or counterclockwise (if you want to adjust it to a lower number). A small screwdriver is a perfect tool to get this done. Avoid turning it beyond quarter-turns. Just make little by little screw turns. Doing so trims down the risk of losing the screw and keeps track of the settings that you look forward to perfect. 

Speaking of tension dials, dressmakers like you must know that the greater pressure is necessitated when you are about to work on thicker threads. To get rid of constant bobbin-case screw fiddling, most experienced dressmakers use two bobbin cases. The first bobbin case set is intended for sewing purposes, while the other bobbin case is used for less frequently utilized threads.

A top and bottom thread is important to create a seamlessly-formed seam. Threads must interlink perfectly in the middle of the material. This is a manifestation of harmony among threads. Imbalance can cause poor quality stitches. It won’t hold tight to the fabric. Worse, you might need to pull them through the other side of the material you are sewing. 

Factory-set bobbin thread tensions cannot easily be adjusted and used for normal sewing. That being said, I will be sharing with you some important information regarding the top thread tension because this is where dressmakers normally adjust. Normally, the dial setting is at 4.5 or the so-called “default position”. For normal straight-stitching projects, this runs at 0 to 9. I must say that this setting is the most appropriate for most types of fabrics or materials. 

If you are working on zigzag stitches such as used in sewing a patch on a backpack, you can easily pull through the bobbin thread on top of the machine. You can see the stitches’ sides so as the slightly bunched or raised fabric. When this happens, all you have to do is loosen off the tension a bit. Having it at 3 and 4 is perfect. This way, the fabric lies flatter on the machine’s surface. 

Loosening the machine’s top tension for a bit helps most especially when you want to work on a uniquely- designed stitches. If you are topstitching, this is an ideal thing to do. 

Every sewing machine has a unique tension setting. As I mentioned earlier, the thickness of the thread also defines the tension setting. The fabric’s weight also do matters. Go ahead and experiment to find the best tension setting for your project whether it is hemming jeans or creating a quilt. Creativity has no limits, so as tension settings.

How To Set Sewing Machine Tension Adjustment

Tension adjustment comes in two different types. The first type is basic adjustment. This is used for regular sewing projects. You will be amazed to know this tension adjustment type that is usually done by repair persons can be done by you. The second type of tension adjustment is temporary adjustment. This is a type of adjustment needed every time you change your sewing machine’s threads. The size of the threads is determined by the size and type of fabric that you are working on. 

The first type of tension adjustment is done by choosing a complementary thread color based on the size, brand, and type of material that you plan to use most often. Make sure to utilize a single-colored thread to fill the spindle. Next, set the sewing machine on an average speed. This is to lessen the danger of extending or stretching the thread unto the machine. Then, thread the machine by placing a new needle beforehand. Make sure that the needle you are placing is of the same size of the thread that you frequently use in your day-to-day sewing. On the machine head, you can see different thread guides. Use this awesome feature to skip threading the needle eye the traditional way. 

How To Set Sewing Machine Tension Adjustment

A 2 mm-stitch length is the recommended length for usual stitching. However, you can set it on the length that you look forward to use regularly. The upper-tension regulator must be set at an average range. This means at a range between 4 or 5. Now, using the two layers of lightweight cotton cloth, have a test seam. This time, check the stitches very carefully. Whenever necessitated, you may utilize a magnifying glass to look at the stitches meticulously. When you see any flaw on the stitches, this means that the tension needs to be well-adjusted. Adjust it the bobbin spring. You can tighten the spring when you see that the bobbin thread is a little wobbly. At this point, look at the bobbin thread located on the upper layer. If it has an underlayer, loosen the bobbin spring. This time, perform test seam one more time. Pay attention to the stitches. It you need to repeat every step you just to achieve a balanced stitch, please do so.

To be able to form uniform stitches on the different sides of the fabric such as needed when sewing a baby blanket, make sure that there is a similar amount of thread flowing from the bobbin and the bobbin at the same time. You can do this by running the thread using tension discs, thread guides, bobbin-case spring, tension regulator, and other tension devices. There are sewing machines that contains a small-holed bobbin-case finger. Such type of a machine lets you improve the tension by merely feeding the bobbin thread through it. An improved tension means a more defined stitch whenever you perform embroidering, satin-stitching, and topstitching. What makes it more impressive is the fact that you need not touching the tension settings at all.

You might have heard about tension assembly at some point or another, haven’t you? When we speak of tension assembly, we mean tension regulator and tension discs together. The ones that squeeze the thread the moment it passes through it, is called a tension disc. On the other hand, it is tension regulator that regulates the level of pressure that occurs on tensions discs. 

Unlike newer sewing machine models, older ones only have two tension discs. These discs are said to be regulated by a knob or a screw. A more sophisticated sewing machine takes pride of having three discs on them. All these discs are regulated by a key pad or a dial that is located on the front. These discs work by controlling two threads at the same time. 

Tension regulators are plain and simple. When you want to adjust the tension higher, you turn the regulator in a clockwise direction. When you do, the tension discs move closer to each other. As a result, the amount of pressure on the discs increases.

On the other hand, turning the regulator counterclockwise moves the discs apart. This gives the tension discs a lesser amount of pressure. It is a must-known fact that sewing using a thicker thread increases the amount of pressure on the discs. This normally happens when you don’t opt any dial resetting. However, more sophisticated sewing machines that have automatic upper-tension adjustments do not work this way. The fact that this machine’s bobbin tension does not self-adjust, you need not manually adjust the tension dial to manually match the machine setting. 

Factors that Affect Stitch Balance

Below are the factors that affect stitch balance:

Factors that Affect Stitch Balance


Duck cloth, batiks, and denims are fabrics that are known for being densely-woven. Sewing this kind of materials makes the top thread more exposed to friction. On the contrary, seaming loosely- woven fabrics like that of knits and quilting cottons lets the thread to get through the material’s fibers with no trouble. This is because it has lesser friction. Fabrics like these have lesser tension on those threads, most specifically during stitching. 


It increases the amount of strain present in the top thread. Every time stitch formation happens, batting can double the level of stress on those threads. Of course, it must be noted further that all these depend on density and loft. In particular, polyester batting grabs lesser as compared to cotton batting. As a result, it attracts lesser amount of friction on threads when sewing. 

Bobbin Thread

Unlike filament polyester threads that are smooth, the cotton thread needs to be set at a higher tension number. There are times when dressmakers prefer those threads that require a lesser amount of tension. This commonly happens when patching or repairing quilts. MasterPiece, a popular cotton thread, is highly-admired by dressmakers across the globe, most especially when it comes to sewing quilts and piecing. Smooth bobbin threads are most-loved (as well), particularly when sewing metallic and other decorative threads. 

Top Thread

The top thread’s material, as well as its thickness, influences stitch balance and quality—thick top thread like that of a 30-wt. Polyester thread needs a more loosened tension dial. Doing so allows the machine to accomplish a seamlessly even stitch on thick materials. 

Here’s another catch, folks! The idea of combining different types of fiber in sewing is never a bad idea. There is nothing wrong with it though. Let say, for instance, a cotton thread above a polyester thread in a bobbin is doable. The thickness is approximately at 50 wt. thread in a bobbin and 40 wt. thread above it. 

There are circumstances that you need to loosen the tension numbers to be able to hit the appropriate (or should I say, balanced) stitches. Metallic threads, for instance, is indeed a stunning thread that is used as a decorative. Unfortunately, such threads are not as powerful as polyester quilting threads. The latter type of thread has 40 wt.. For this reason, using it might require you to turn the tension number down to 1.0. This tension level means very loose. Remember that mixing various types of threads can still accomplish seamless and balanced stitches as long as you know, the proper technique of tension adjustments.

Wrapping Up

I hope that this article about sewing machine tension numbers has helped you, in one way or another. I have tried my very best to explain it in the simplest and easiest way possible. I believe that by now, you already know what to do with those numbers on your sewing machine’s tension dial. If not, then there is no need to worry because practice makes perfect. Just keep on practicing until you get a hang of it!

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