A: Looping on the underside, or back of the fabric, means the top tension is too loose compared to the bobbin tension, so the bobbin thread is pulling too much top thread underneath. … In this case, it might be necessary to loosen both the bobbin tension AND the top tension.
Stitches are loose on the top and/or bottom
- The upper threading could be threaded incorrectly. …
- Check the bobbin. …
- Change the needle.
- Check the combination of the needle and thread size as well as the fabric you are trying to sew on. …
- Using a scrap piece of material sew out your stitch and adjust the thread tension.
If your thread is pulled tight on the underside and not forming an even stitch then (counter-intuitively) it’s usually the top thread tension that’s wrong. Sometimes very lightweight fabrics such as sheers can get dragged down into the machine so it’s a good idea to use a straight stitch plate.
Why does my sewing machine keep jamming underneath?
However certain you are that the problem with the machine is most likely due to a huge tangled mess of thread in the bobbin underneath the fabric, the most common reason for the jamming is usually the lack of sufficient tension in the upper thread.
What should the tension be on a Brother sewing machine?
The normal tension setting is 4.0. The upper thread and the bobbin thread should cross near the center of the fabric. Only the upper thread should be visible from the right side of the fabric, and the bobbin thread should be visible from the wrong side of the fabric.