Patent attributes
An insert portion (3) of a reamer (1) is fixed, using screws (8), to a leading end portion of a body (2A). The insert portion (3) is configured by overlaying an insert (4) for finish machining and an insert (5) for rough machining, and forms a right hand cut right hand helix. On respective mating faces of the inserts (4, 5), convex portions and concave portions of the mating face of the insert (4) overlap with concave portions and convex portions of the mating face of the insert (5). The reamer (1) can enlarge a hole formed in a workpiece or change a shape of the hole. The inserts (4, 5) simultaneously cut an inner peripheral face of the hole, and can thus perform rough machining and finish machining in one pass. By overlapping the convex portions and the concave portions of each of the mating faces of the inserts (4, 5), they partially overlap in their respective thickness directions. A protrusion length of the insert portion (3) can thus be shortened.
