There is a small iron block on the vehicle as a ruler, and the pointer swings to 0. When the needle bar reaches the lowest position, the lower end point of the needle bar just reaches the lower end face of the ruler, and it is measured with the semicircular plate that originally supported the ruler.
After work, insert the needle into the pinhole plate, lift the presser foot, and cover the nose with a hood to prevent dust from invading; When starting work, first check the main machine parts, how heavy they are trampled, whether there is any special sound, whether the needle is normal, etc. If abnormal phenomena are found, they should be repaired in time; The machine has been used for a long time and should be overhauled. If worn parts are found, replace them with new ones.