Abstract
As a consequence of consideration of the situation where the side-flow of metai appears in three-dimensional cutting such as lathe operation, the authors have been led to conclude that the side-flow revealed at the machined surface makes the practical longitudinal roughness on machined surface always larger than its theoretical value depending on the tool geometry and the feed even when the influences of built-up edge and vibration are neglected, and that, on the other hand, the side-flow revealed at the workpiece surface must be a cause of tne groove wear on flank of cutting tool.
Moreover, it was known that the practical roughness of machined surface becomes better by using the cutting tool with smaller end-cutting-edge angle, and that Kolesov type tool with a cutting edge parallel to the centre-line of workpiece is fairly effective to raroduce good machined surface over the wide range of feed.