Plunge milling cutter

A high-density plunge milling cutter for milling camshafts, comprising:

• a thick-walled cup-shaped body attachable to a drive spindle in driving engagement;
• said cup-shaped body having a rim provided with a multiplicity of inclined seats each having therein a block shaped indexable cutting insert with its active cutting edge disposed to sweep a conical cutting path about an apex in front of the cutter and with said cutting edge disposed forwardly of a parallel radius of the cutter so as to move diagonally in a cut tangent to said conical cutting path;
• each said insert seat comprising a principal seating surface which is pitched away from said cutting path both in the radially outward direction and in the circumferential direction opposite to the cutting direction, and an edge-seating surface perpendicular to said principal seating surface;
• said block shaped insert comprising a hard cutting material of generally parallelepiped form having two parallel major plane surfaces serving respectively and interchangeably as a major seating face emplaced upon said principal seating surface and as a clearance face for the insert;
• said insert also having opposed, plane parallel minor edge surfaces perpendicular to said major surfaces and serving respectively and interchangeably as a cutting face and an edge-seating surface of the insert emplaced against said edge-seating surface of said insert seat;
• each insert also having therein a hole passing between said major surfaces and countersunk from each and a countersunk-head retainer passed through said hole and into said cutter to secure said insert in engagement with both said seating surfaces of said insert seat;
• the clearance face of each insert receding from said conical cutting path to the bottom of the cutting face of the succeeding insert to form with said cutting path and said cutting face a triangular chip space for said succeeding insert;
• said minor edge surfaces of each insert each having therein a pair of grooves each extending the full width of said minor edge surfaces parallel to said major surfaces adjacent thereto with a plane mid-portion of said edge surface between said pair of grooves;
• said major plane surfaces of each insert having thereon adjacent to each of said minor edge surfaces a narrow land extending the full width of said minor edge surface, each said land making an acute exterior angle with said major plane surface and intersecting the adjacent groove of the adjacent minor edge surface at an acute angle to form therewith straight and parallel cutting edges along at least two opposite sides of each of said major plane surfaces, said disposition of said cutting edge relative to a parallel radius, and the rake of said groove at the cutting edge, resulting in positive effective shear in said cut.