1. We know that the outer contour of the needle handle (thick) and the needle (thin) are parallel. First place the needle on the needle plate of the machine head. The flat surface of the needle handle is close to the plane of the push plate. Hold the needle handle with the thumb to make the needle tip float, and check whether the distance between the needle and the plane of the push plate is the same. If the distance is the same, the needle is vertical, such as squatting or bending, indicating that the needle is faulty and cannot be used.

2. Check the needle can also use another method: the head or the stylus holder is no problem. Turn the needle off so that the needle is exposed by the pin handle. Use a medium screwdriver to loosen the small connecting screw and turn the needle bar to see if the needle is curved when it is rotated. If there is a curved shape, the needle or needle bar is out of specification. On a sewing machine that is not required to be high, such as the needle tip on the needle bar is directly aligned with the needle plate hole, and the needle is freely inserted during sewing, and the needle is normally normal.