The Modified SAE EP Lubricants Testing Machine and the McKee EP Lubricants Testing Machine use two contacting cylindrical test cups which are rotated at different speeds under load to give combined rolling and rubbing action typical of gear teeth. With these machines methods were developed for evaluating the anti-wear and the load-carrying properties of turboprop lubricants. Data are presented for 31 oils tested on the above machines, and for 25 of these oils also tested for stability at high temperatures on the McKee Oil Stability Apparatus.Contributed to the American Society of Lubrication Engineers by the author. Manuscript received 1 October 1957.