A highly creative sewing artist is hard at work, when suddenly, everything changes. The scene fills with frustration, heartache, and panic.

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.

There are many possible causes of bad sewing machine tension. One of the common causes of improper tension comes from faulty threading of the upper thread or bobbin assembly. Missing a thread guide, threads floating on top of the upper tension discs, or threads missing the bobbin tension can cause havoc with the stitch quality. Rough spots, worn surfaces, lint and debris, burrs on the hook, bad needles, and bad thread can also cause faulty tension.

Properly set tensions should produce stitches with the upper and lower thread locked together in the center of the fabric. When you look at the seam from the top side, you should see a smooth even flow of thread with tiny holes into the fabric. When you turn the fabric over, you should see exactly the same quality stitching as you saw from the top side. The stitches should be snug and show no extra threads on top or bottom.

Tension is simply the resistance created by the sewing machine to guide and manipulate the thread making it do what it is intended. When this resistance is adjusted correctly, the upper thread and lower thread mechanism balance each other. The result is a quality stitch without excess threads where they should not be.

Imagine the fabric is a stream of water. The threads are like ropes across the stream. One tug of war team pulls up and another pulls down. Each team pulls across the stream. If the lower team or bobbin team pulls harder than the upper tension team, excess thread will collect under the fabric out of sight until you lift the fabric to see ugly bunches of thread. It may even look fine on top while the threads jam up underneath. If the upper team pulls harder than the lower team, excess threads pop up on top of the fabric. Usually, you will see bubbles, balls, or bunches of thread almost as soon as they stitch.

Remember, your goal is to provide the same or equal tension from the upper and lower threads.

The first thing you should do when you see messed up tensions, is to rethread the upper thread. Are you using a spool cap? Check for any rough spots that might snag the thread. Check for any debris or lint in the tension discs. Before threading the tension mechanism, lift the presser foot. Make sure everything is right. When you reach the needle, tug on the thread. It should draw smoothly with very little resistance. Put the presser foot down and pull again. Now there should be significant resistance.

The bobbin tension is usually more dependable than the upper tension. However, lint and debris can collect under the tension spring. Also if you change the size of bobbin thread, you will need to adjust the lower tension. To make this adjustment look for a tiny slotted screw pressing down on the bobbin tension spring. Turn right to tighten or left to loosen. You may prefer to have a professional make this adjustment if it is necessary.

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.

You may notice irregularities on one side of a zig zag stitch and not on the other. Test and adjust until it looks the best you can make it. Some machines have design issues that make a perfect zig zag stitch almost impossible. If you want a perfect stitch and you have one of these older machine, consider getting a better machine.

Now that you understand how your sewing machine tensions works, you can use your sewing machine with renewed confidence. Make the adjustments you need when you need them. Always remember, a trip to the sewing machine shop can relieve stress when all else fails.