A cutting fluid should have specific characteristics to be effective at cutting metal. Here are some of the major properties to look out for:

• Good heat transfer performance: This will reduce the amount of heat given off during cutting and therefore reduce the chances of accidental fires. It also ensures the metals will not be ruined by excessive heat.
• Good lubrication performance: This is very important, reduction in friction reduces the amount of heat produced and therefore increases the tool life.
• Cutting fluid should flush chips away from the work surface.
• It should prevent rusting of the cutting tools and materials.
• It should not corrode the tools or the metals.
• The cost of the cutting fluid should be relative and proportional to the output.
• The cutting fluid should be environmentally friendly to dispose of without causing any pollution.
• People handling the cutting fluid should be able to use it comfortably without having to worry about its toxicity levels.

Always read the product labels before purchasing any cutting fluid to make sure you are buying the right product for your specific needs. If the work you are performing is light duty, less heat will be produced and the task is even easier to complete.

Cutting fluids undergo maintenance using a refractometer to check the concentration of the soluble emulsions, checking the pH levels and checking the amount of tramp oil, the hydraulic oil that leaks into the cutting fluid system. Over time the fluid will degrade due to bacterial growth and tramp oil; as this happens, discard the cutting fluid in a safe, environmentally friendly manner.