Cutting Fluid

Cutting fluid is a type of coolant and lubricant designed specifically for metalworking processes, such as machining and stamping. It is essential for high-speed machining to prevent tool failure and improve surface finish.

Description of what it is like

It can be a neat oil (clear or dark), a soluble oil emulsion (milky white), or a synthetic fluid (clear or colored). It feels slippery and has a distinct chemical or oily smell.

Origin and where to find it

• Synthetic: Created by mixing specific oils and chemicals.
• Natural base: Can be made from animal fats (lard) or vegetable oils, often mixed with water and soap.

Minimum processing required

• Neat Oil: Use Lard Oil or Vegetable Oil directly for slow, heavy cuts (like threading).
• Soluble Oil (Emulsion): Mix oil with an emulsifier (like Soap) and then whisk into water. This provides the cooling of water with the lubrication of oil.

Tools needed to work on it

• Containers: For mixing.
• Pump/Squirt Bottle: To apply it to the cutting zone.

Common forms of use

• Flood Coolant: Pumped continuously over the tool and workpiece.
• Mist Coolant: Sprayed as a fine mist (uses less fluid but bad for lungs).
• Hand Applied: Brushed or squirted on for manual machines.

Possible substitutes

• Water: Great cooling, zero lubrication, causes rust immediately. (Add Soda Ash to reduce rust).
• Kerosene/Diesel: Good for aluminum and finishing steel (flammable!).
• Dry Machining: Possible with carbide tools, but generates immense heat.

Limitations and common failures

• Bacteria: Soluble oils can grow bacteria and smell like rotten eggs. Require aeration or biocides.
• Evaporation: Water evaporates, changing the concentration.
• Rust: If the mix is too lean (too much water), the machine will rust.

Risks and safety

• Dermatitis: Prolonged skin contact causes rashes.
• Inhalation: Breathing mist is bad for lungs.
• Fire: Neat oils can catch fire if the machining gets too hot.

Related materials

• Vegetable Oil: Base for bio-fluids.
• Animal Fat: Lard is an excellent tapping fluid.
• Water: The main component of coolants.
• Soap: Emulsifier.