An end milling tool having a positive axial rake angle in side elevation to facilitate removal of chips from the surface of a workpiece and a curved cutting edge having a neutral (zero) to positive rake angle in bottom plan view as it progressively cuts to enhance chip removal while precluding welding at the work area and enabling the use of a low cutting force. The tool cutting area is formed by a rhomboid-shaped indexable cutting insert at one end having an angular axial rake with a unique curved surface in side elevation provided with a lead corner and a strong included angle in an end elevational view. Other inserts are mounted on the tool above the rhomboid insert to form the remainder of the cutting area and are circular in side elevational view. Each of the rhomboid and circular inserts are mounted in an insert seat having at least one pair of flat side surfaces in abutting relationship with compatible surfaces in the pocket to obtain maximum rigidity in seating and prevent rotation of the insert. The inserts are mounted in adjacent helical rows adjacent to and each having a curved cutting edge portion extending into a helical flute or slot.
