Which type of cutting fluid is typically composed of mineral or vegetable oil?

Straight oil is typically composed of mineral or vegetable oil and is designed to provide effective lubrication and cooling in various metal cutting applications. This type of cutting fluid is used in situations where high lubricating properties are needed, such as in heavy machining operations or when cutting hard metals.

Straight oil does not contain water or emulsifying agents, making it particularly effective for reducing friction and wear on cutting tools, which extends their lifespan and enhances surface finish on machined parts. The absence of water means that straight oils can also be more resistant to microbial growth, which is sometimes an issue with water-containing fluids.

In contrast, other types of cutting fluids involve mixtures or emulsions with water or other additives. Emulsion oil, for example, combines oil with water to create a milky fluid that offers cooling and lubrication. Water-soluble oil contains a proportion of water and is often diluted for use, whereas cutting compounds may include various additives for specific functions but don't have a primary composition of pure oil.