(Guessing here) Ordinary oils are designed to lubricate in a way that prevents or minimizes metal on metal contact/wear. Cutting oil is designed to lubricate in a way that enhances metal on metal contact/wear.
Use an ordinary lubricant on a tap, or at a drill press. Then use cutting fluid. You will see the difference in how it works.
thats what i expected was being claimed.
cutting oil or fluid is designed to minimize friction, and heat, same as "ordinary" oils. it cools the work, and the cutting head or drill, and lubricated the two surfaces to prevent tip welding and dulling. Cutting oil or fluid does not in any way cause any sort of cutting action, or enhance metal to metal wear. it is a lubricant, designed to minimize wear and heat, allowing the cutting edge/ surface to what its supposed to do. it also helps flush away chip material, allowing the cutting edge to work cleanly.
cutting fluids are just thin mineral oils or blends of mostly water and light oil. water is a great cutting fluid, but promotes rust. no abrasives whatsoever in them, as it would ruin cutting edges quickly. using WD40 or light weight non detergent motor oil, or 3in1 type oils are normal cutting fluids that are used often.
if you want something with a "cutting action" i would suggest a fine grit lapping compound. and then flush it our fully with brake cleaner after they loosen up some.
