Patent ID: 10384276

Abstract:
An insert portion (3) of a thread mill (1A) is fixed to a leading end portion of a body (2A) using screws (8). The insert portion (3) is configured by overlaying an insert (4) for finish machining and an insert (5) for rough machining. On respective mating faces of the inserts (4, 5), convex portions and concave portions of the mating face of the insert (4) are overlaid with concave portions and convex portions of the mating face of the insert (5). The thread mill (1A) can cut a female screw in a hole formed in a workpiece by performing right-hand cut down-cut milling, for example. The inserts (4, 5) simultaneously cut an inner peripheral surface of the hole, and the rough machining and the finish machining can thus be performed in a single pass. By the convex portions and the concave portions of the respective mating faces of the inserts (4, 5) being overlaid with each other, the inserts (4, 5) partially overlap in their respective thickness directions. As a result, a protrusion length of the insert portion (3) can be shortened.