The reel chain, the ear box shaft, the elevator chute, the returning machine, the universal joint, and the transmission chain of each part of the corn harvester should be used once. The oil is used for the chain, butter is used for other parts, and the table gear is used. The box, small transmission box, returning machine transmission box, returning machine chain cover once in a season, use gear oil on it. Pay attention to the amount of oil in the tank, not too much nor too little.