On older machines there are only two tension discs, controlled by a screw or knob. On newer models there are three discs controlled by a dial or keypad on the front of the machine. Unless you have a newer machine that makes automatic upper-tension adjustments, using a thicker thread without resetting the dial will increase the pressure and cause the upper thread flow to decrease.
Both the spring and screw are easy to locate when the machine has a separate bobbin case. When the machine has a drop-in bobbin with a built-in bobbin case, locating the tension screw can be more challenging but a little bit of searching will prove it’s there. In either case, to increase the resistance, use a small screwdriver to turn the screw clockwise (to a higher number) or counterclockwise (to a lower number). Turn the screw in small increments and never more than a quarter-turn between tests.
Most domestic sewing machines are of the “lockstitch” variety. That means an upper thread and a lower thread “lock” together. When they don’t “lock” together properly, you could have an issue with the tension.
Remember you want your stitches to look even on both sides of your fabric. If the thread is so tight it’s causing the fabric to bunch around it or if the stitching is loose and falling apart, you might have an issue with the tension. If your stitches look perfect and your sewing machine is sewing wonderfully, don’t touch your tension knobs!
An easy way to think of the thread balance is tug of war. You have your top thread and your bobbin thread pulling on each side. If they’re both pulling equally, the seam will be even and consistent. If one side is pulling too much, the thread from the other side will be visible. If the bobbin thread shows on the top side of the seam and the top thread is straight, the upper tension is too tight. If top thread shows on the underside of the seam and the lower thread is straight, the upper tension is too loose.
Incorrectly threaded machine: Is all of the thread running through the thread guides? Is thread unwinding freely from the spool or is it catching? Is the bobbin inserted correctly? Dirty machine: Thread ends can get lodged between tension discs, around the bobbin case, and under the throat pale. This can cause an increase in resistance and restrict the thread flow. Check all of these areas to ensure they’re clear. Damaged machine parts: Bent needles and bobbins and rough or damaged surfaces on the needle eyes, thread guides, tension discs, take-up lever, throat plate, presser foot, bobbin case, or in the bobbin area can all cause problems. Give your machine a general inspection and remember that even the tiniest damage can distort tension.
Polyester thread is a a true all-purpose thread, and it’s a good choice for most sewing projects. Wool thread, on the other hand, is very thick and if you were to use it, you’d have to adjust your tension. [4] X Research source Common heavy duty fabrics include canvas and burlap while cotton and polyester are common fabrics with a standard weight. If you’re switching between heavy fabrics and something of a lighter weight, you’d have to adjust your tension to keep the stitches even. [5] X Research source Needles come in various sizes for different purposes. There are thicker needles designed for denim that won’t break when they’re being used and thin needles that won’t damage thin, delicate fabrics. When buying needles, you can consult someone in the store to help you find the best option for your fabric. [6] X Research source
If you are unable to get it completely even, proceed to adjusting the bobbin tension.
If you are unable to get it completely even, proceed to adjusting the bobbin tension.
With a bottom loading bobbin, an easy way to test the tension is to take the thread hanging from your bobbin case in your hand. If it doesn’t unwind at all, your tension is too tight and needs to be loosened. If the thread unwinds with no effort, your tension is too loose and you’ll need to tighten it. You want to hold the thread and have it drop just a few inches. When that happens, your tension is perfect. [9] X Research source Use a tiny screwdriver and turn the screw on the side of the bobbin case by ¼ turn. Turn it right to increase the tension and left to decrease it. Test the tension again. Repeat until the thread only drops a few inches. Similarly, with a top loading bobbin, you use a screwdriver and turn the screw by ¼ turn, testing your tension between each adjustment with a test seam on scrap fabric. The good old righty tighty lefty loosey applies in this situation as well.
