1. The threading sequence is incorrect. Solution: Rethread in the correct sequence. Sewing machine accessories wholesale.
2. The upper thread is too tight. Solution: Slowly loosen the thread clamp nut and adjust the tension of the bottom thread accordingly.
3. Improper needle selection. Solution: Replace the needle corresponding to the thread and sewing material.
4. The needle is bent. Solution: Replace the needle.
5. The needle hits the presser foot. Solution: Adjust the position of the presser foot. Sewing machine accessories wholesale.
6. The shuttle does not rotate smoothly or is not installed in the right position. Solution: Adjust the shuttle position to the correct position and tighten it.
7. The shuttle hook is damaged. Solution: Polish the shuttle hook or replace the shuttle.
8. The needle eye is rough, or the needle groove of the needle plate is damaged. Solution: Polish the needle eye hole or needle groove. If the needle groove is severely damaged, it should be replaced with a new one.
9. The upper thread is moldy or too brittle. Solution: Replace the thread. Sewing machine accessories wholesale.
10. The hook is hooked too fast or too slow. Solution: adjust the hook time.
