The measurement of temperature distribution at the flank surface of a cutting tool is characterized by the extremely small extent of the surface over which the temperature field is explored. This paper describes a technique which makes use of a moving lead-sulfide, photoconductive, infrared radiation detector. The surface in question is quickly scanned by the detector’s view field. For the level of temperature encountered, data are reproducible and the method may be used to determine temperature distribution over sliding contacts in general. From the measured flank surface temperatures, tool-chip interface temperature distribution was deduced using geometrical, electric analog. The technique also has the general application in finding steady temperatures at locations which are not accessible for direct measurement. The computed tool-chip-interface temperature profile agrees well with known crater-wear patterns. Tool-face frictional force calculated from thermal considerations compares favorably with independent dynamometer measurement.