General Refractories Company

Charles Lamar Turner

The invention provides a hollow mill cutting tool capable of forming a cylindrical pin on one face of a plate member by removing material from the plate member. The cutting tool comprises a generally cylindrical member terminating in a tip portion having a toroidal cross-section and having its axis aligned with the cylindrical member. The inside diameter of the protruding end of the tip portion is selected to be the desired diameter of the cylindrical pin. The tip portion includes a plurality of forward helical surfaces each terminating at a forward end in a cutting edge extending across the thickness of the toroidal cross-section. Each helical surface extends rearwardly along a cylindrical path from the cutting edge at an angle of about 8.degree.-11.degree. with a plane transverse of the axis of the cylindrical member. A back helical surface, which is inclined at an angle of at least 55.degree. to a plane parallel to the axis, is connected to each of the foward helical surfaces. A generally longitudinally-extending surface is connected at one end to the forward end of one of the forward helical surfaces to form a cutting edge, and the other end of each longitudinally-extending surface is connected to the rear end of an adjacent back helical surface.

Extrusion die and cutting tool for machining such a die

Sintered ceramic articles having a high surface area-to-weight ratio and containing a plurality of ducts that extend through the article to permit fluid flow therethrough are prepared by forming an extrudable admixture of pulverized ceramic material. The admixture is forced through a forming zone in which initial shearing forces form the admixture into a plurality of discrete ribbons, and the discrete ribbons are flowed into the upstream ends of a plurality of spaced, longitudinally-extending members to form a web member containing a plurality of longitudinally-extending ducts as the ribbons flow together about the members. Monolithic ceramic structures formed by the above-described process and including hexagonally-packed circular ducts, that is, circular ducts surrounded by six other circular ducts with each surrounding duct spaced an approximately equal distance from the axis of the circular duct it surrounds, exhibit a desirably high ratio of transverse compressive strength to longitudinal compressive strength.

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Delran, NJ, United States of America

Charles Lamar Turner