[Glenn]

So, let me put this in writing.

If you drill a hole and use motor oil as a lubricant to CUT the metal, this is the same oil you put into your car engine to lubricate and NOT TO CUT on the metal to metal surfaces, bearings etc.

If you drill a hole and for whatever reason (too much speed, dull drill bit, etc) the metal gets hot, the motor oil can act as a quench, hardening the metal you want to cut. The same oil you dip the hot metal into to quench it so it will become REAL HARD.

No wonder the industrial cutting and drilling operations FLOOD the cutting surface with the PROPER coolant for the job, keeping the metal both cool and the cutting tool and the cut well lubricated.