End mill with throw-away tip

An end mill comprising:

• an end mill body having an axis of rotation therethrough and having forward and rearward ends, said forward end having a forward end face and a circumferential surface, said forward end having at least one pocket formed therein and opening to both said circumferential surface and said forward end face, said pocket including a tip receiving recess having a bottom face facing in a direction of rotation of the body, said body having a core receiving recess formed at a center of said forward end face;
• a throw-away tip comprising a plate having upper and lower surfaces, said upper surface having a first cutting edge ridge, a second cutting edge ridge intersecting the first cutting edge ridge and a third cutting edge ridge intersecting the second cutting edge ridge, said tip being releasably mounted in said tip receiving recess with said lower surface held in contact with said bottom face of said tip receiving recess in such a manner that the first cutting edge ridge is located so as to protrude radially outwardly from the circumferential surface to serve an an outer peripheral cutting edge, that the second cutting edge ridge is located so as to protrude forwardly from the forward end face to serve as an end cutting edge, and that the third cutting edge ridge is located so as to protrude radially inwardly of the body into the core receiving recess to serve as an inner peripheral cutting edge, said end cutting edge being inclined toward said rearward end of the body as said end cutting edge approaches the axis of the body;
• and
• shift preventing means for preventing said throw-away tip from being shifted during a cutting operation of the end mill, said shift preventing means comprising an engaging recess formed in one of the bottom face of the tip receiving recess and the lower surfce of the throw-away tip and extending axially of the body and a projection complementary to said engaging recess of the shift preventing means and formed on the other of the bottom face of the tip receiving recess and the lower surface of the throw-away tip so as to be brought into engagement with said engaging recess of the shift preventing means.