Many see the fluids as an unnecessary evil to the grinding process, failing to realize that selecting the right grinding fluid can lead to significant improvements in cycle time, surface quality, finishes, secondary operations, such as tool coatings. Oelheld has put together a short article on grinding oil considerations.
The oil-off (also known as loss-of-lubrication or oil-out) performance evaluation of gears is of significant interest to the Department of Defense and various rotorcraft manufacturers, so that the aircraft can safely land in an accidental loss-of-lubricant situation. However, unlike typical gear failure modes such as pitting or bending fatigue where early detection is possible, gear failure in an oil-off situation is very rapid and likely catastrophic. Failures rapidly result in the loss of torque transmission and the inability to control the aircraft.