Types of cutting fluid

 Cutting fluids are classified in seven main groups. They are:

1.Water

Water is only used in rare cases as coolant because of its corrosiveness.

2. Soluble oil

Soluble oils are emulsions composed of 80 percent on more of water, soap and mineral oil. This is milk like in appearance and most widely used cutting fluid in all machining applications.

3. Straight oils

Oils like animal oil, vegetable oils, mineral oils, kerosene etc. are used in light machining and hand cutting operations like drilling, tapping, dieing etc.

4. Mixed oils

This is the combination of straight mineral and straight fatty oil. 

5. Chemical additive oils

Straight oil or mixed oil mixed with sulfur or chlorine is known as chemical additive oils are also used as cutting fluid.

6. Chemical compounds

These compounds consisting mainly of a rest inhibitor, such as sodium nitrate, mixed with a high percentage of water and used on machined surfaces where formation of rest is to be avoided.

7. Solid Lubricants

Stick waxes and bar soaps are sometimes used as a convenient means of applying lubrication for different machining operations.