The workpiece material can adhere to the cutting tool. This typically occurs when a work-hardening material is cut at low speeds. The adhered material is called a built up edge, or BUE. If the BUE becomes thick, the workpiece can be cut by the BUE and not the cutting tool. This may adversely affect surface finish or tolerance of the machined part. This movie shows a BUE form, cut the workpiece material, and then come off the tool without a trace. A machinist looking at the cutting tool after a cut might never know that a BUE had interfered with the cutting process. Steel workpiece, 200 m/min surface speed. Elapsed time is shown in milliseconds (ms). The visible light movie on the left is 5 000 frames per second with a field of view of about 23 mm wide. The visible light movie on the right is 5 000 frames per second for some portions of the movie and 180 000 frames per second for other portions. The field of view is about 0.7 mm wide.