A custom, high-bandwidth (40 Megapixels/sec) microthermometry system, the only one of its kind, was designed, manufactured and utilized to acquire dynamic thermal images of steady state chip formation by focusing on the tool-chip interface on a microscopic level. The microscope apparatus was used to acquire dynamic thermal images of the tool-chip interface during orthogonal machining operations performed on a high-speed machining center, which was operated as a high-speed lathe.;The system was calibrated using another one-of-a-kind technique that eliminated the need for emissivity measurements. The resulting calibration curves allowed the thermal images to be converted to temperature profiles, which are the first of their kind, with the highest resolution achieved (5-10 micrometers) in research thus far. These measurements were performed on AISI 1045 and AISI 4140 steels for wide ranges of cutting parameters, and their results were compared with finite element analysis.;The comparison results, despite conservative uncertainty estimates, from 30 degrees Celsius to 76 degrees Celsius, demonstrated that simulations over-predict maximum temperatures along the rake face of the cutting tools and under-predict the distance from the tool tip that those maximums occur. This indicates that while simulation software is a reliable means of predicting temperature trends with respect to cutting parameters, it is not necessarily a reliable tool for predicting the actual temperatures present during machining processes.