: ( 1) The oil water ratio of soluble oil cutting fluid has to be checked from time to time and when water evaporates, the amount of water decreases. In such cases, the ratio of coolant with water is to be maintained. (2) Cutting fluid can be infected by bacteria and rot and spread bad odor. In this case, the cutting fluid needs to be changed from time to time. (3) Body parts cannot be kept in contact with cutting fluid for long. If it gets on the hands, it should be washed immediately or there is a risk of skin infection. (4) The speed of cutting fluid should be determined depending on the diameter of the job and the job-material. (5) Cutting fluids used for ferrous metals should not be used in nonferrous metal machining.