Annular hole cutter

A method of manufacturing a tipped annular hole cutter comprising the steps of

• (a) forming a cutter body to have a cylindrical wall with outer and inner surfaces and a free end surfaces;
• (b) making tip-receiving slots with a preselected orientation in said free end surface of said wall, each said slot being associated with a respective one of said flutes, said cutter body having an intended direction of rotation about an axis of rotation;
• (c) forming tips of relatively hard material, each tip including a leading face, a trailing face, an inner face, an outer face, a tip surface and a bottom face, said inner face having a preselected inclination, each tip further including lands on at least one of said leading and trailing faces, one of said lands being an outer land which adjoins said outer face and another of said lands being an inner land which adjoins said inner face;
• (d) choosing the preselected inclination of said tip inner face in relation to the preselected orientation of said slots so that the tip inner face defines a radially inner clearance face without grinding said tip inner face subsequently to the hereinafter recited heating step (f) of securing said tips to said wall;
• (e) inserting said tips in said slots so that said leading faces of said tips face in said intended direction of rotation and so that said outer land engages said outer wall surface and said inner land engages said inner wall surface, whereby said tips are accurately radially located in said cylindrical wall;
• (f) circumferentially uniformily heating said cylindrical wall, at least in the vicinity of said tips, to secure all said tips to said wall simultaneously by a metal fusion operation;
• and
• (g) thereafter grinding at least said top surfaces of said tips to form end clearance faces which, together with said leading faces of said tips, define cutting edges.