Importance

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Abstract

A drilling tool having at least one helical fluid flow channel at its interior, composed of a hard metal core having an exterior surface and a hard metal tubular casing having an interior surface, the casing enclosing the core with their surfaces in firm contact so that the core and casing form a composite body, each channel being formed as a groove in the surface of the core or casing. A method for manufacturing a sintered body having at least one internal channel, by providing a hard metal core having an exterior surface; providing a sinterable and heat shrinkable hard metal tubular casing having an interior surface which initially encloses a region larger in cross section than the core; forming in the surface of the core or casing at least one groove corresponding to the at least one channel; inserting the core into the casing after the step of forming a groove; and after the step of inserting, finish sintering at least the casing and shrinking the casing for bonding the core and casing together at the surfaces by diffusion. An extrusion molding tool for forming an extruded member having a helical surface groove from a blank forced through the tool, the tool including: a die; a mandrel disposed to be enclosed by the die; and a radially protruding web mounted on the surface of the die or mandrel and having a helical form in the direction in which the blank is forced through the tool.

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First Claim