1. The upper thread is floating
Analysis: The tensioner pressure is too small.
Treatment method: tighten the wire and increase the tension of the cotton thread.
2. The bottom line is floating
Analysis: The shuttle spring is too loose.
Treatment: Tighten the bobbin screw to increase the tension of the bottom thread.
3. The length of the stitch is short and long.
Analysis: The presser foot pressure is too small.
Solution: Tighten the pressure screw.
4. Each needle under the sewing material has a thread sleeve, which is in the form of a towel line.
Analysis: The feeding and picking actions do not match.
Treatment method: Adjust the feeding cam screw to make the feeding and the thread take-up action match.