Abstract: A cutting tool, preferably for milling, includes a holder and a cutting insert mounted thereon. The holder includes a seat upon which the insert is mounted, and an upstanding wall structure against which an edge face of the insert is pressed. The edge face has upper and lower portions separated by a step. The upper portion is frustoconical and is pressed against an upper wall of the wall structure to frictionally resist rotation of the insert about the insert's center axis. The lower portion of the edge face is polygonal and is adapted to engage a lower wall of the wall structure at a location spaced radially inwardly from a location where the upper portion and upper wall make contact. The lower portion rotates into engagement with the lower wall in response to cutting forces acting on the insert, to create an interference relationship between the lower portion and lower wall which prevents further rotation of the insert.

Abstract: A metal cutting drill includes a shank having cutting edges at a front end and helical flutes extending rearwardly from respective cutting edges for conductive cutting fluid away from the front end. The cross-sectional area of each flute, as seen in a plane oriented non-perpendicular to an axis of rotation of the drill, becomes progressively smaller in a rearward direction. A helix angle defined by each flute becomes progressively smaller in the rearward direction. An angle formed between the plane and another plane oriented perpendicular to the axis equals the helix angle at the location where the planes intersect each other and the axis.