Abstract
In order to clarify the effect of the cutting velocity magnified up to a actual range and a simulated tool in the shape of square pyramid on the mechanism of chip formation in a single grit grinding was practiced. Cutting action was arrested by a quick-stop device. The behavior of material in front of tool face during cutting was observed minutely on the cross-section along the cutting direction of a groove. In addition, these present results were compared with previous ones used a single grit simulated conical tool. A stagnating region beneath the tool face was found, it served as a kind of tool, and was apt to form the chip. It was clear that the stagnating region formed by a simulated square pyramid tool was more extensive than that made by a simulated conical tool.
