Usually, the fluid used to cool cutting tools is water.

Cutting oils

Emulsifiable oils

Chemical cutting fluids

because the material may be safe lubricate and may not require cutting fluid .

Roughing fluid is a type of cutting fluid used in metalworking to cool and lubricate the cutting tool during roughing operations such as milling or drilling. It helps to dissipate heat and reduce friction, prolonging the tool life and improving the surface finish of the machined part.

Cutting fluid should be avoided on certain materials. If not that can lead to mess that can and will be unfixable.