Coated hard metal tool

Claim 1

A cutting tool having a rake face and flank face which intersect to form a cutting edge, said cutting tool comprising a substrate consisting of a sintered hard alloy containing at least one carbide of Group IVa, Va and VIa elements of the Periodic Table and a metal binder selected from the iron group metals and a coating film provided thereon, made of a material with a higher hardness than the substrate, which is at least one material selected from the group consisting of carbides, nitrides, carboxides, carbonitrides and oxides of Group IVa, Va and VIa elements of the Periodic Table and aluminum, and solid solutions thereof, said coating film near the cutting edge having such a thickness that the thickness continuously increases in directions away from the cutting edge along both the rake face and the flank face from a minimum value, including zero, at the cutting edge, such that the thickness of the coating at the rake face reaches a maximum thickness at a first distance from the cutting edge and the thickness at the flank face reaches a maximum thickness at a second distance from the cutting edge, the first distance being greater than the second distance.