Lubricant or coolant is not always required when cutting a material. However, in some cases it can be beneficial to obtain maximum tool life and optimum cut quality, provided that the correct type of cutting fluid is used.

Coolant or Lubricant?

Coolant is the term applied to soluble oils where dilution in water takes the heat away from the cutter and workpiece. Coolants should be diluted to the manufacturer's instructions and applied as a continual spray mist.

Lubricant is the term applied to the use of neat soluble oils. These are not efficient in removing heat. Soluble oil or paraffin lubricants may be spread or brushed over the surface of the material being cut. PTFE is normally available as an aerosol spray and may likewise be sprayed over the surface of the material or directed periodically at the cutter.

Coolant or lubricant is most often required for cutting metals, eg:

Copper, Brass, Bronze: Soluble oil (depending on hardness)
Aluminium: Soluble oil or Paraffin
Steels and stainless steels: Coolant