Diamond parts, diamond parts, and diamond material

摘要

A tool with a through hole comprising a substrate and a diamond part held in the substrate, wherein the diamond part is set to L1 when the length along the center line of the through hole is L1, and the maximum value of the diameter of the equal area circle of the area surrounded by the outer edge of the cross section with the center line as the normal is L1 / M1 which is the ratio of L1 and M1 is 0.8 or more.