Disc Tensioner

A complete disc tensioner unit suitable for longarm quilting machines.

The tension assembly is necessary to add resistance to the top thread. This resistance is what ensures the stitches lock in place. Without a tension assembly, the top and bottom thread will not interlock correctly – which makes for a very weak, unattractive seam.

In most sewing machines, this resistance is controlled by a spring and two or three plates – called the tension plates. The thread goes in between these plates, and the spring pushes the plates together. As you tighten the tension, the spring presses harder against the plates, which makes it harder for the thread to pass through – creating the resistance we need.

The biggest thing the tension affects is the appearance of your seams. Even with a low tension, there is still resistance on your top thread – which means the top and bottom thread will properly interlock with each other. However, where they interlock will change with your tension setting.

More resistance = a stronger pull.

When your sewing machine locks the top and bottom thread together, the two threads both pull away from each other. If the resistance on either side is uneven, you will not have a very attractive stitch. The easiest way to check your tensions is with two different colored threads.

Strong Top Thread Resistance

If the resistance of the top thread is stronger than the resistance of the bottom, you will see the bottom thread pulled to the top of the fabric. The top thread will not be visible at all from the bottom side of the fabric.

Strong Bottom Thread Resistance

If the resistance of the bottom thread is stronger than the resistance of the top, you will see the top thread pulled to the bottom side of the fabric. The bottom thread will not be visible at all from the top side of the fabric.

Equal Thread Resistance

If you have an equal amount of resistance on the top and bottom thread, you will barely be able to see the top thread on the bottom side of the fabric, and the bottom thread on the top side of the fabric.

In our longarm machines we need to set our Bobbin Tension first as in my video here

Then we can adjust our top tension until the tension is balanced with the stitches forming in the middle of the quilt sandwich.