The authors report results of a series of tests made to determine the lubricating effects of a wide variety of cutting fluids on the forces involved in drilling. The investigation was conducted in the metal processing laboratories of the University of Michigan. Torque and thrust, from which the coefficient of friction was obtained, were measured on a special lubrication dynamometer and recorded graphically. Brief specifications are given for the cutting fluids used. The technique for carrying out lubrication tests and the results obtained are discussed, as well as those for the drilling tests. A comprehensive series of graphs showing test results accompanies the paper, and clearly defined conclusions are drawn from the investigation.