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.
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.
You should see a small screw on the flat/closed side of the bobbin case. Turning the screw a tiny bit counterclockwise will loosen the bobbin tension; turning it clockwise will tighten the 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 knotting underneath?
If your sewing machine thread is not properly threaded, the bobbin thread won’t be pulled up into the fabric the way it needs to be. Occasionally the upper thread can catch on a moving part or get stuck, which impedes the easy flow of thread through the needle, creating a tangle.
Why does my thread keep coming out of needle?
The upper thread was not threaded correctly. The spool is not installed correctly, the spool cap is too big for the spool being used, or the thread has come out of the needle bar thread guide. Rethread ensuring that the spool is installed correctly and using a spool cap that matches your spool size.