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. By tightening the top tension, the loops will stop, but the added tension may cause breakage, especially with sensitive threads.
How do you fix a thread loop under fabric?
Looped stitches are usually caused by improper tension. If the loop is on the upper side, it may be corrected by loosening the top tension or by tightening the lower tension. If the loop is on the under side, it is usually best corrected by adjusting the upper tension.
What causes the bobbin thread to bunch up?
Bobbin Thread Tangling
The bobbin keeps pulling and jamming collecting a lot of thread beneath your fabric. There are several culprits for this ranging from a dull needle, improper threading or tension. The tension in both your upper and bobbin threads need to be even. The bobbin could also be placed incorrectly.
Why is my bottom stitch not straight?
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.