I cant stand it anymore. These tensions are all screwed up.



Perhaps the most common complaint sewing machine users make, is about their tensions. In a sense you might say poor sewing machine tensions cause extreme user tensions. The sewer may sew along thinking all is fine, only to cry out in anguish when the turn the fabric over to see gobs of unsightly tangled threads. Or the thread may pucker up in little balls on top of the fabric.

The problems with sewing machine tensions may result from many different things. Threading is often a problem. You may have threaded your sewing machine a thousand times, but if the thread rides along the ridge of the tension discs, you get problems. Dirt, grit, gunk, and lint can cause the system to mess up. Rough spots, irregular surfaces, burrs, and rust can ruin tensions. Loosely wound bobbins, bad thread, dull needles, and of course mechanical failures can produce tension problems.

When the tensions are properly set, the top and bottom threads link inside the fabric. The stitching should flow evenly, tightly, consistently over the length and breadth of the seam. There should be no puckers, bubbles, or gobs of thread bunching up underneath or showing on top. There should be no excess thread top or bottom.

To achieve these perfect stitches the upper and lower threading must be just right. The drag or resistance of the upper tension system and the bobbin tension system must balance each other precisely.

If you think of the top and bottom thread systems like two tug of war teams, it may help us understand what is actually happening. Each team pulls on their rope. If one team pulls harder than the other, it gets more rope on its side. If the other team pulls harder, it gets the extra rope. In this case, we are talking about thread instead of rope, but the analogy still applies. Therefore, if you see extra thread on top of the fabric, what do you know? Yes, the upper thread system is pulling harder than the lower one. Or the lower one is pulling less than the upper one. In the same way, if you see excess thread on the bottom what do you know?

When you see tension problems, do not panic. All you have to do is modify the resistance on the top and bottom until they equalize.

Begin your corrective efforts by rethreading the upper thread. Be intentional and careful to insure everything is just right. Remember to lift the presser foot while threading. Watch out for anything that might snag the thread. Check to make sure not lint or gunk has messed gotten stuck between the tension discs. Watch out for rough spots. Once you reach the needle, gently draw on the thread two or three inches. You should feel very little resistance. The thread should flow smoothly. Now drop the presser foot, and test again. Is there more resistance? Good.

Take your bobbin out. Is the thread wound evenly? It should be. Place it back in its carrier. Check the tension spring for any debris or lint that may have collected under it and clean it out. Slide the thread under the tension spring. Test it to make sure there is moderate resistance on the thread. This usually does not require adjustment unless you change the size of thread significantly. Some suggest that a professional sewing machine repair person make these adjustments when needed.

Then turn the top tension knob to regulate the upper tension until it matches the lower tension. Experiment until you are satisfied. This is not an exact science. It is more of an art. If the knob is turned so it wont go any further and it is still now balanced, have a technician check it out. The tension assembly itself may require disassembly and repair.

Testing is good. Using scap material sew a seam using a straight stitch and then a moderate zig zag stitch. Check the quality of the stitch? Are the tension balanced? Do you see any problems? If so continue to experiment until you are satisfied. Remember, if you test on scrap, before sewing on your fine finish fabric, you will save loads of frustration and sew with greater confidence.

When you sew a zig zag stitch, you may see minor flaws on one side of the zig zag and not the other. This is sometimes due to the a design flaw in the sewing machine itself. If after making several attempts to adjust for this irregularity you still see slight problems. Reduce the length and/or width of the stitch. Adjust it so that any irregularities you may still see are consistently underneath the fabric instead of on the facing side. This way no one will ever see the flaw.

When you understand how your sewing machine tensions work, you can adjust them with confidence. In those rare instances where your best efforts fail, you can always rely on your local sewing machine repair technician.