This amazing image shows just how the top and bottom threads work together to create the perfect stitch. See how the yellow and green threads meet right in the middle of the fabric. This is what perfectly balanced tension looks like on a lock stitch sewing machine.
Most tension problems can be fixed by adjusting the top tension dial on your sewing machine. But sometimes you will need to adjust the bobbin tension to balance your tension. Adjusting your bobbin tension is easier than you think. We'll show you why and how.
I love thread!! All kinds; cotton, silk, gorgeous light reflecting tri-lobal polyester, metallics, even glow in the dark. As a quilter, sometimes I like thread to blend in so I might use a thin very fine thread. Sometimes I may want thread to stand out so I use a thicker thread for a bolder line. But I also use thread for piecing and binding, appliqué and embellishing. This is why we need to adjust thread tension.
If I want to use a variety of threads in lots of different ways I will need to make tension adjustments. I'll always try the top tension dial first, If that doesn't solve the problem then I move on to the bobbin.
Sometimes the bobbin tension has been set too tight at the factory. This is a common problem and is easy to fix. Take your bobbin case out of the machine. Hold the tail of the thread like in the diagram on the left, once again compliments of sew it simple. Hold the tail of thread firmly and give it a short sharp shake. It should drop a couple of inches and then stop.
If it doesn't drop then the bobbin tension is too tight. Get a small screw driver. Look at the screw. Think of the line in the screw like the minute hand on a clock. You are only going to turn the screw in very small 15 minute increments. Remember righty-tighty and lefty-loosey. Turn the screw a quarter turn to the left and give it another shake. If it still does not drop, repeat the process. If it drops too far or too fast then tighten it up a bit righty-tighty. Be sure to keep track of how many quarter turns you make so that you can get back to where you started.
For free-motion machine quilting I am finding that a looser bobbin tension works best for me. If my bobbin tension is loose enough then I am able to maintain a good thread balance by simply adjusting the top tension dial as I work with a variety of different threads.