About skipping stitches
1. The backlash and height position of the needle and the rotary hook are wrong and the direction is wrong (check the standard on the manual of the repairer to correct it.)
2. The needle is bent (replace the needle)
3. The thickness of the needle and sewing material are not commensurate (choose the appropriate needle [9-14 for thin fabrics, the smaller model 14-18 for thick fabrics])
4. The bottom thread tension and presser foot pressure are too weak (increase the bottom thread tension and presser foot pressure)
5. The needle is short and the model is wrong (choose the appropriate needle)
About disconnection
1. If the line is not adjusted properly, the line will break (the best way to adjust the line is to adjust the bottom thread first. The bottom thread should be adjusted after the thread core is placed in the bobbin case. It is advisable to hold the thread in one hand and slowly drop the bobbin case down. Adjust the noodle thread according to the bottom line)
2. If the gap between the shuttle bed and the needle tip is too large, the thread will break (the distance between the hook and the needle groove should be 0.1mm when the shuttle bed is adjusted, and the needle is easy to break if it is less than 0.1mm.)
3. If the presser foot is not adjusted properly, the thread will break (when the presser foot is adjusted, there is friction between the presser foot and the needle. When adjusting the presser foot, use your hand to shake the presser foot to see if it will touch the needle)
4. If the fabric is too thin, the thread will break. (The presser foot comes out of the fabric and the thread breaks during sewing)
5. If the fabric is too thick, it will break (tighten the screw on the top of the presser foot to make it a certain amount of pressure)
6. If the needle bar and the shuttle bed are not synchronized, the thread will break (when adjusting the needle bar, use the shuttle cover on the needle plate, and the needle bar has just been adjusted to the height of a shuttle cover, and then the shuttle bed)
7. The needle hole of the bur is too sharp and the thread will break (recommended to use a round needle)
