THROWAWAY TIP AND THROWAWAY TYPE BORING TOOL THEREWITH

摘要

PROBLEM TO BE SOLVED: To make improvements in the dischargeability of chips by efficiently subdividing them into pieces. SOLUTION: This throwaway tip is made up into being nearly parallelogrammatic plate form, and both first and second cutting edges 15 and 16 bent in a nearly doglegged type each toward the outside together are crossed each other via a nose part 17, and set up into each paired rotation symmetry. The first cutting edge 15 is made up by having a circular arcing cutting edge 15a at the side of the nose part 17 and a rectilinear cutting edge 15b crossed via a first bending part 15c. The second cutting edge 16 is made up by having two rectilinear cutting edges 16a and 16b crossed nearly at an obtuse angle via a second bending part 16c. An outer edge tip 10A directs the first cutting edge 15 of the throwaway tip to the tip side of a tool body, and an inner edge tip 10B directs the second cutting edge 16 respectively, while the nose part 17 of the outer edge tip 10A is attached after turning it toward the tip outer circumferential side of the tool body.