Abstract: An indexable insert for cutting internal and external grooves in a workpiece is adapted for mounting and securing upon a tool holder having a pocket therein; whose bottom edges define an obtuse angle. The insert comprises an elongated body of rectangular cross section having a flat top surface along one edge of the body and a pair of angular bottom surfaces extending from a central point of the body and inclined toward and extending to said top surface at a corresponding included obtuse angle. These inclined surfaces define a pair of separately usable transverse cutting edges at the opposite ends of said body which is adapted for snug registry within said pocket. Said pocket also defines within the tool holder a back up plate against which the insert bears. The insert, one or more, is held down within said pocket by a clamp which bears across the top edges of said inserts. A cam lock device is also mounted upon said holder to apply lateral pressure to the insert holding it snugly against the back up wall.

Abstract: A rectangular shaped cutting tool having an upwardly, forwardly and sidewise opening V-shaped recess formed in one side face, with the edges of the V being uniformly sloped to form an acute angle with the inner wall of the recess, and a replaceable triangular shaped cutting insert formed of a hard, brittle metal, having its edges bevelled to correspond to the slope of said edges, vertically positioned in the recess and jammed downwardly and against the recess inner wall by both an upper releasable clamp and by cutting forces upon the exposed cutting corner of the insert. The uniform slope of the recess edges and its three openings permit the interchangeable use of inserts which are inaccurate or slightly variable in thickness and edge length. The improvement wherein the insert edges are bevelled from its opposite faces to define a cental raised ridge along its edges, rather than from one side, to allow the insert to be used in either left or right hand insert holders interchaneably.