Rotary cutting tool and reversible cutting insert having variable-width minor relief surfaces therefor

Abstract

In a rotary cutting tool used for milling operations, a reversible cutting insert is removably secured in a cutting body. The cutting insert has two opposing end surfaces interconnected by a continuous peripheral surface, which includes three side surfaces alternating with three corner surfaces. The side and corner surfaces intersect with both end surfaces at side and corner edges, respectively, with each side edge having a major cutting edge, and each corner edge having a corner and minor cutting edge. Each minor cutting edge has a projected minor cutting length, in an end view, and each associated minor relief surface has a minor relief width between two lateral boundary points contained in a horizontal plane, varying with an offset distance between the horizontal plane and a median plane. Each projected minor cutting length is greater than the maximum minor relief width of its associated minor relief surface.