In this video, we walk through running a FOX test to fine-tune embroidery machine tensions. Unlike H, I, or O tests, which are used for general tension checking, the FOX test provides a more refined look. We use the word "FOX" because the F sews both horizontally and vertically, covering movement in both the X and Y directions. After sewing, we stop the machine, remove the hoop, and examine the back of the embroidery to check the tension balance.
In our example, the black thread looked too light, indicating a tension problem. We identified the issue with needle number seven and tightened the tension accordingly. Since each tensioner contributes roughly one-third to the total thread tension, we made small, careful adjustments. To verify the correction, we hooped fresh backing material and reran the FOX test, sewing only with the black thread multiple times if needed.
After the first adjustment, we noticed that we had overcompensated, resulting in too much bobbin thread showing. We loosened the tension slightly and ran the test again. With each round of adjustments, the results improved, showing more top thread and less bobbin. Although it took a few tries, we moved steadily toward the goal of achieving approximately one-third top thread, one-third bobbin, and one-third top thread across the satin stitches.
This process highlights that adjusting tension is not a perfect science—it often takes a few iterations of sewing, inspecting, and tweaking to get it right. The key is aiming for balance rather than perfection, and being patient while making small corrections until the results are within reason.