Patent ID: 8092126

Claim:
An indexable drill comprising: an approximately cylindrical rod-like drill body which rotates around an axis; and a cutting insert which has cutting edges at a tip and which is removably attached to a distal side of said drill body; wherein said drill body comprises: a recessed part at the tip which is recessed toward a proximal end side; the recessed part forms a bottom face which faces said distal side and which is orthogonal to the axis of said drill body; a pair of clamp faces that clamp and hold a portion of said cutting insert which inserts into said recessed part; a pair of torque transmission faces which are crossed by and adjacent to each of the clamp faces and which transmit the rotary force of said drill body to said cutting insert; a slit which extends toward the proximal end side in said axial direction so as to bifurcate the tip of said drill body from said bottom face; and an insertion hole that is formed at the distal side of said drill body, said insertion hole extending across said slit and having an inner surface that comprises a first female screw part and a second female screw part, wherein a female screw of said first female screw part and a female screw of said second female screw part are formed in mutually inverse directions; wherein said cutting insert comprises: a pair of clamp receiving faces which are respectively pressed by said pair of clamp faces of said drill body; a pair of torque receiving faces which are crossed by and adjacent to the clamp receiving faces and to which is transmitted the rotary force of said drill body from each of said paired torque transmission faces; and crosshatch angles of said clamp receiving faces and said torque receiving faces which are adjacent in said cutting insert are formed smaller within a range of 2° or less than the crosshatch angles of said clamp faces and said torque transmission faces which are adjacent in said drill body.