DIY Mill/Lathe Cutting Fluid For Steel

Sick and tired of the high cost of cutting fluids? Are you a do it yourself kind of person? For the cost of some cheap motor oil, dish washing fluid and a little time, you can make huge amounts of lathe or mill cutting fluids for pennies. For about $3-$5, you can make about 4 gallons of steel cutting fluid! Professional cutting fluid can easily run $200 or more for the same volume. Why not buy yourself some new tools for the shop instead!?


  • 1 qt. of motor oil
  • 3 cups of dish washing liquid
  • 4 gallons of water


  • Purchase the necessary products. Motor oil can be found at your local gas station and dish washing liquid at convenience stores and supermarkets.
  • Add the liquid soap to the water. Mix the soap into the water so that it is dissolved. The soap is the catalyst that will enable the oil and the water to mix; otherwise the different densities will make the oil float on top of the water.
  • Pour in the motor oil. Make sure that the water and the oil are mixed properly together with no separation. The water will act as a coolant in the cutting oil, while the oil acts as the lubricant, as the water is evaporated off by the heat generated in the cutting process.


  • If a sticky residue is left on the cutting tool following use, then the cutting oil mix contains too much soap.
  • A great deal of heat is generated in the cutting process, so a fire extinguisher should be kept handy as a precaution against the oil catching fire in the cutting process. When using this cutting oil, cutting machines should be set to a slower speed.