Sewing Machine Tension Adjustment – All that I know!

I would rather not touch any dial on my sewing machine, if I could, as I am awkward with machines. Why make it worse!. The sewing machine tension adjustment is one such anathema I do under gunpoint. It is enough to raise the tension of any sane sewing mind. But there are somethings that are unavoidable at times

Sewing machine tension refers to the balance with which the thread is threaded through the machine – it may be tight or loose or balanced and balanced is what we aim for. You need a perfect lock stitch on your stitching line that would not be pulled out by just a tug but that will join the fabric layers beautifully without any wrinkles or distortion. Do you have that? If you have, then you are in a happy place. Go and read another sewing post.

When the tension is not balanced in your sewing machine you may have loose threads, looped stitches, puckered fabric, bunching of the seam – all sewing nightmares your sewing grandma warned you about.

All your sewing problems are not courtesy of tension. Other than tension it may be due to not properly threading the machine – see that it is done properly. Another problem may be a bad thread or not filling the bobbin properly or overfilling it. If these problems or any as mentioned in this post on 25 common sewing machine problems are ruled out, then only check the tension. Sometimes a little lint or stray thread can cause a lot of problem in the tension area – so a regular  maintenance of your sewing machine is a must before you make tension changes

Some new generation high quality prohibitively expensive sewing machines come with automatic tension adjustment – And you may not want to go against the manual and do experiments on those but even then, if you are having trouble with your sewing you may want to turn the tension knob.

Sewing Machine Tension

There are two types of tensions on a sewing machine – the upper or top tension and lower or bobbin case tension. The tension of the top thread is controlled by the tension dial. And that is usually the culprit for your sewing tension troubles.

Adjustments on these are not needed for regular sewing purposes, like you only sew with one type of thread or one type of fabric throughout – but that is not to be.  When you change from a cotton thread to a polyester thread sometimes the trouble starts; or use different type of thread for bobbin and top thread or when you start sewing that beautiful sheer after sewing long with cotton. Not always because you use thin fabrics with interfacing or interlining etc but they do cause problems occasionally which is when you have to play with the tension

There are two basic scenarios when you started thinking about sewing machine tensions.

Fist scenario is – you do not have a big problem but there is some balance issue with the stitches. The second scenario is you have big trouble – there are loops on the top, on the back and all hell breaks open and you want to hang up your sewing shears and go do cooking instead! By God! 

What happens when you move the tension dial?

When you adjust the tension dial it opens and closes to loosen or tighten the top thread passing through the discs, changing the tension of the stitch you make . As you go up the numbers (clockwise) the higher the tension; a lower number (anticlockwise) means lower tension

How do you know you have off tension?

Let me start with the perfect sewing scenario – you can say you have correct sewing machine tension when the top thread and the bobbin thread lock themselves to form a link that will lie in the middle of the fabric layers you are stitching. The seam stitching will be balanced, not too tight, nor too loose. The joined fabric will not be wrinkled, distorted or puckered due to the stitching at all.

Then there is improper tension.

Sewing stitch balance problem

If the link I talked about earlier is a little to the top ie bobbin thread shows up on top  or worse the fabric puckers at the seam. This is a result of the thread being pulled too much through the fabric layers.  This means the top thread is too tight and you have to lessen the tension a bit

If the link is a little or more to the bottom this means top tension is too loose. In this case, when the sewing is done you can easily pull the thread out of the fabric from the stitching line. Here, you will have to increase the top thread tension.

When you move the tension dial and reaches the optimum tension this is the result

Stitches are a mess

Just look at your stitching problem – if the understitching on the back of the fabric (ie the bobbin thread) shows a problem it is the top tension you need to adjust. If the topstitching shows a problem you will need to deal with the lower tension. But before thinking of adjusting the lower tension do all the adjustments with the top dial.

Some common sense things to do before changing sewing machine tension

Before you start a new project or you use a new type of thread, always Check the tension of your machine on a scrap piece of the cloth you are going to start sewing on,  The thickness of the thread and its weight can change the balance of the stitch.

When you are trying to experiment with the tension in your sewing machine, thread it with different colored threads (preferably contrasting colours, so that you can see the problem clearly ) on top and on the bobbin and use a scrap muslin fabric.

Before experimenting with the dial for adjusting the tension remember or better, write down the number that is currently on your machine- otherwise, you may end up in a madhouse if this experimenting with tension doesnot work for you.

First, see if the tension dial is working or not.  Keep the presser foot down and pull the thread. If the thread is tight this means that the tension dial is doing its job and you just need to make some adjustments

How to change the sewing machine tension

On your machine the tension adjustment is done on the numbered dial on the face of the machine – it is the tension regulator for you. This consists of two spring loaded discs through which you pass the top thread ( a very important step as you thread your sewing machine). When you move this dial clockwise or anticlockwise the pressure on the thread that passes through these discs increase or decreases.

Move the dial clockwise  – This will increase tension

Move the dial anticlockwise   – This will decrease tension

Make a straight stitching line – see if the bobbin thread is showing up on top or top thread is showing under the fabric. Make adjustments in the tension till cannot see this misalignment. A perfect balanced stitch can be achieved and maintained this way.

When sewing thin fabrics – you loosen the tension

When sewing thick fabrics – you tighten the tension

When sewing with heavy thread – you tighten the tension 

Lower /Bobbin tension adjustment

If the sewing is all wonky on the face (top) of the fabric and you have ruled out all the possible causes you will have no other way but to adjust this tension.

A machine with the detachable bobbin case

There is a small screw on the bobbin case that you can tighten or loosen.When sewing with metallic thread elastic thread etc the tension has to be loosened in this bobbin otherwise it wouln’t work.

Works the same way as the top tension – you tighten to increase tension and loosen to decrease tension. 

A Machine with the inbuilt bobbin case

In these machines, you just drop in the bobbin in the designated space which is the built-in bobbin case. There is a small case adjustment screw inside the area that you can see and adjust with the small screwdriver. This can be moved clockwise to tighten and anti-clockwise to loosen it

Sewing tension adjustment is not nerve-wracking as it sounds; keep on experimenting and your machine will be a winner in the tension game


Comments 2

  1. Thank you for this information. My bottom tension is really loose. I have a Singer Fashion Mate 257. It is an older model but a very strong machine with not that many hours of sewing done on it. I can’t seem to get the bottom tension set right. Any suggestions. Thanks!

  2. Thank you for the information. My fabric puckers when I sew and I will try some of your solutions. The suggestions given by the “experts” at the National Sewing Circle were not as good as your explanations–so my “Thank You” is heartfelt.

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