Abstract: The subject invention is directed to metal working operations and, more particularly, to machining heat resistant super alloys (HRSAs) such as titanium alloys with polycrystalline diamond cutting inserts sintered on a carbide substrate. Using at least one cutting insert mounted upon a rotary toolholder and wherein the at least one cutting insert has a substrate with a top layer of PCD secured thereto over no less than 1/3 of a substrate top surface, a method of machining heat resistant super alloys (HRSAs) is made up of the steps of rotating the rotary toolholder such that an insert surface speed rate is above 50 meters per minute and adjusting a tool feed rate (advance per tooth per revolution) and/or radial engagement of the toolholder such that the machining operation produces chips having a thickness of approximately 0.050-0.200 millimeters.