The bobbin of the external machine needs to pay attention to many matters, otherwise it is easy to present many problems.

1. When cutting the thread, the bobbin pin should be pressed against the bobbin, and check whether the bobbin pin can work.

2. Replace the bobbin with an aluminum bobbin, which can reduce the inertia of the bobbin movement due to its light weight.

3. Install the bobbin in reverse so that the direction of rotation of the bobbin is opposite to the direction of inertia of the bobbin.

4. The winding amount of the bobbin should not exceed 85% of the outer diameter of the bobbin.

5. Reduce the sewing speed when using, especially when the thread trimming stops.

6. Choose the rotary shuttle with anti-idling reed.

7. Or put a piece of flannel on the bottom of the ordinary rotary hook bobbin to increase the friction resistance of the bobbin.

8. The gap between the used bobbin and the bobbin case should be as small as possible.