Heavy duty insert

A cutting insert comprising a unitary body of a hard wear resistant material having a bottom, upstanding side walls, end walls, and rounded corners in a generally rectangular configuration, cutting edges adjacent to and extending around the periphery of said side walls and rounded corners, a mesa spaced inwardly of said cutting edges and said walls, and a chip breaker groove extending generally longitudinally of each side wall between each of said cutting edges and said mesa, each said cutting edge having a land immediately adjacent its associated groove which land extends generally transversely to the side wall associated with such groove, a face between and inclined to both said land and associated side wall, and a generally arcuate surface interconnecting said face and associated side wall, each said groove having a substantially uniform cross-section essentially throughout the portion of the groove extending longitudinally of its associated side wall with a first portion immediately adjacent the land of its associated cutting edge which first portion extends generally inwardly and downwardly below the plane of such land and a second portion inwardly of said first portion which second portion extends generally inwardly and upwardly from the bottom of such groove, and said mesa having a wall adjacent said second portion of each groove which wall is inclined inwardly with respect to its associated groove and extends upwardly to at least the plane of the land of the cutting edge association with such groove.