This section only deals with tension adjustment not sewing machine problems. If you have a sewing fault see my Fault Finding section.
For many people tension adjustment is an enigma inside a riddle. The mere thought of altering the tension makes some people shudder and run for the gin. Others move toward the machine, in fear, circling a few times, muttering to themselves, before attempting to touch anything. I have known people throw sewing machines out of windows. I have seen women cry and men get mad over this one topic. Growing up in a factory full of sewing machines I soon came to learn many new words, that I passed on to eager classmates at school, all because of the humble sewing machine. I know someone—a man—who threw an industrial machine out of a third-floor window because of tension adjustment.
Well, the truth is that it is actually very easy to adjust your machine's tension so long as you follow simple procedures. Before we start I must mention one point, although it is mainly women—over 90%—that sew, many men also sew; designers, upholsters, tailors, sail makers and so on. This adjustment pages works just as well for both sexes.
TOP TENSION ADJUSTMENT
Let's get started
look at your machine.
As you sit at the machine most of them have a tension regulator directly facing the user. A numbered dial that may go from 1-9 or 1-4 or, on older machines, it may simply be a knob that turns. On some older machines the tension regulator is on the end of the machine.
All tension regulators work on the same principle. The upper thread passes between two spring-loaded discs. By turning the dial clockwise or anticlockwise you increase or decrease the pressure on the thread as it passes through. Do not be afraid to turn your tension dial. A skilled operator may alter the tension many times while sewing a garment that varies in thickness.
Go try turning your dial.
Now did that feel good? Once you get used to adjusting your tension you will be able to impress friends and influence people. Well, not quite, but you will have the satisfaction of being the most popular person in your quilting class!
In reality most of these machines use the same old dials with the numbers removed and AUTOMATIC written on them. I know, I sell them. There are a few complex computer machines that also boast automatic tension, but they still can have trouble. It is a great selling point but you do need to learn to adjust your tension. There are those few computer machines that really do have self-adjusting mechanisms, but we are not concerned with them.
As you turn the dial clockwise, you are increasing the tension. Anticlockwise, decreasing it. The lighter the pressure on the dial the lighter the upper tension is in the fabric. What we are looking for, in a perfect stitch, is one that is interlocked evenly in the middle of the fabric layer.
There are the usual classic faults in tension. Loose threads, looping, puckering, bunching and many more. What we want to do is eliminate them all by understanding the simple procedure of tension adjustment. I have listed on my linked Fault Finding Page all the other faults that effect your sewing machine and that are not covered by tension adjustment.
OK, so here goes. We know that a simple twist of the wrist can be the difference between a perfect stitch and one that drives you crazy.
Firstly we must make sure the tension unit is working. Whatever number your tension dial goes up to, place it at half that, so you are in the middle of the dial. If your dial is un-numbered, turn from lowest to highest tension and judge the halfway point, set the adjustment to that point.
Put a reel of thread on your machine and thread the monster. Finally pull the thread through the needle's eye with the foot raised.
Check that this is working. Pull the thread through with the foot up, then lower the foot and see what happens when you pull the thread with the foot down. It should become tight to pull.
If the thread is not tight enough to bend the needle—
Back to business. Now that we have made sure the tension unit is working we need to adjust it to get a lovely stitch in your work. What we must do at this point is find an average balance for the average material. So get some normal fabric, say a strip of clothing-weight cotton cloth. Fold it double as if you were going to sew a seam. Place it under the machine and start to sew. Now examine the stitch. Remember what we are looking for—a balanced, even, stitch on the top and bottom, with the lock right in the middle of both layers.
Back to business. What we need to do now is to alter the stitch according to what the problem is. The lower section of the page deals with lower tension adjustment. I must impress on you that you should carry out Upper Tension Adjustment first, as this is much easier and the most common cause of a poor stitch, 9 times out of 10 in fact.
If you have a perfect underneath stitch but a straight-line stitch on top and turning the tension dial has no effect, go to lower thread adjustment, further down the page.
What is the problem with your stitch? Is it all loopy underneath? This is the most common problem.
So, here we are at last, down to the nitty-gritty. It is so simple that it hurts. By adjusting the top tension clockwise the loops will slowly disappear. Run along about 6 inches of fabric and examine the underneath stitch. Alter the numbers one at a time, say from 4 to 5, check each time you do. Keep going until you find that the top and bottom match. Remember the hands? Now, the number that you have reached on your dial is the BALANCE POINT.
Once you have found this BALANCE POINT make sure you remember it. From this number you should be able to sew 90% of all fabrics. You may decrease the number for lighter work, say nets or satin, and increase it for curtains or denim. But always put the tension back to this point.
If the top and bottom tensions are balanced but both too tight the fabric will pucker. Loosen both top and bottom tensions a little at a time (lower thread adjustments) until a smooth stitch is created.
To finish off the top tension adjustment, one final point. It will not matter how many times you adjust your tension dial; master the dial and the world will be yours.
LOWER THREAD TENSION ADJUSTMENT
ONLY FOR THE BRAVE
For those of you who want to escape now! HOME
The classic symptoms of lower tension collapse are quite obvious. Look at your stitch and see if the lower thread has pulled through to the top of the fabric. The underneath will look fine, perhaps a little loose—however, the top thread will be able to be pulled out of the fabric. This is because the loop in the lower thread is laying on top of the fabric, not pulling the top thread into the fabric.
You will notice, with this symptom, that you have little or no effect by altering the top tension dial and often think that it is a top tension dial fault. That is wrong.
OK, so here goes, hold on tight, it is going to get nasty, have your painkillers ready.
Step one, setting the top tension. Assuming that your top tension is working can be a fatal flaw but is easily checked. Most sewing machines, even quite early ones, have automatic top tension release mechanisms. This means that, once the sewing foot is raised, the top thread tension is automatically released so that you can pull your work out of the machine without the thread breaking. To test this simply raise the sewing foot, set the needle to its higest position and see if the thread pulls out easier than if the foot was lowered ready for sewing.
To test if the thread is being held properly by the tension discs, when ready for sewing, you need to lower the foot then grasp the thread where it comes out of the eye of the needle and pull. The thread on all machines should be tight enough to bend the needle when pulled.
If it does not then you need to investigate why it is not tight. The most common reason is a restriction, between the tension discs themselves, caused by fluff, or corrosion or trapped threads. A loose top thread leads to a bunching of thread underneath the work (or looping, with minor tension failure).
Once you have done the test, put your numbered tension dial halfway. For instance if you have a dial that goes from one to four put it on two, one to nine put in between the four and five. Get the idea? On older machines with no tension-dial numbers turn the dial clockwise until the thread bends the needle when pulled through as I have just mentioned.
Then leave the top thread tension alone.
Now the lower tensions fall into basically two types for lockstitch machines. Ones with bobbin cases and ones without. We have to deal with each separately but both have common symptoms and cures so I will take the machines with bobbin cases first.
Now where was I? Oh yes, back to the all important bobbin-case thread adjustment.
Wind a full bobbin of new white thread, the same type that you normally sew with—it is not important if it is silk, cotton, polyester or a mix—just your usual thread. Place the bobbin into the bobbin case and suspend the bobbin by the thread, like a spider hanging from its web. If, when you hold the thread, the case simply drops to the floor you need to adjust the bobbin-case screw clockwise until it just holds its own weight.
Now, while the spider, oops, bobbin and case are suspended by the thread simply jerk your hand a little and see what the case does.
So, when you shake it a little the bobbin case drops a little. This is the MAGIC point, known in the trade as the balance point, for your type of thread. If the case does not move you need to adjust the bobbin-case screw anticlockwise until it drops a little when lightly jerked. Only turn the screw a small part of a turn each time, then dangle-check again. Once you have mastered this adjustment you will be in great demand at all sewing classes as you transform misbehaving sewing machines in an instant.
Note: Only one of the two screws on the bobbin case spring adjusts the tension the other attaches the tension spring to the case and is not adjustable it should always be tight. So, one is tight and the other moves clockwise-anticlockwise (this adjusts the tension of the spring and consequently your machine). It is usually the small left hand screw that is adjustable, it is often slightly larger than the other screw. Nearly always, it is the screw nearest the middle of the small metal tension spring.
Although this is the balance point some machines need to be adjusted slightly tighter or looser for the perfect stitch. When adjusting from this point make only very small movements of the screw, about one sixteenth of a turn at a time. After each adjustment run a trial stitch and examine. Once you are right with the lower tension you can go back to the top tension unit again and make final adjustments, say from a four to a five, or a four to a three, to get it just perfect.
Adjusting the newer type plastic cases that are set permanently into the machine, you know, the ones where you just drop in the bobbin and hook it around the spring plate, is much the same. You need to do this more by feel. You need to FEEL the thread resistance by pulling the thread. One of the ways to do this is to place a fine hand-sewing needle part-way into a cork—Pinch one of your husband's or better still open up a new bottle of wine with dinner!—so that about two inches (50 mm) of the needle is protruding from the cork. Then tie the thread from the machine case through the eye of the needle and, while holding the bottom of the cork, pull the thread. It should have a slight resistance and slightly, only slightly, bend the needle.
If it does not bend the needle you need to tighten the case-adjustment screw clockwise. If it bends too much you need to loosen it a little. Remember, tiny adjustments only. Well, hey presto! that is it.
If you can master lower thread adjustment you will have a control of your machine rather than it controlling you.
One final point—by now the painkillers for that pounding headache have started to work—if you mix your threads it is a lottery whether the tensions will work effectively. The worst culprits are the old wooden reels of cotton that can become hard, springy, weak and sticky. They can really mess up your sewing machine—big time. Try and stick to the same upper and lower threads. If in doubt about a thread bin it! Really, all the grey hairs and profanities it can cause are just not worth it.
I hope this has helped many of you that have a tension problem. Now you know why instruction books hardly ever mention lower thread adjustments.
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