Abstract: A tool insert blank including first and second major surfaces and a plurality of edge surfaces defining an outer perimeter of the blank. A first layer defines the first major surface and a first portion of the plurality of edge surfaces proximate the first major surface. A second layer harder than the first layer is disposed substantially co-extensive with the second major surface and a second portion of the plurality of edge surfaces proximate the second major surface. At least one of the edge surfaces includes a projecting portion defining a first engagement plane and a recessed portion spaced inwardly of the engagement plane whereby the grinding wheel is engageable with the projecting portion without engaging the recessed portion. The second layer can be formed out of various materials including polycrystalline diamond and cubic boron nitride materials. A method of forming a tool insert blank is also disclosed.

Abstract: A tool insert blank including first and second major surfaces and a plurality of edge surfaces defining an outer perimeter of the blank. A first layer defines the first major surface and a first portion of the plurality of edge surfaces proximate the first major surface. A second layer harder than the first layer is disposed substantially co-extensive with the second major surface and a second portion of the plurality of edge surfaces proximate the second major surface. At least one of the edge surfaces includes a projecting portion defining a first engagement plane and a recessed portion spaced inwardly of the engagement plane whereby the grinding wheel is engageable with the projecting portion without engaging the recessed portion. The second layer can be formed out of various materials including polycrystalline diamond and cubic boron nitride materials. A method of forming a tool insert blank is also disclosed.

Abstract: A multidirectional electrical discharge machine wire guide that is long-lasting and easily manufactured and, wherein the guide member thereof is not subject to dislodging. The guide member is made of a wear-resistant material, such as diamond or the like, and includes a wire hole for receiving a wire electrode therethrough and guiding the wire. A non-conductive member is provided and prevents electrical current flow between the wire electrode and the guide assembly at an area substantially near the guide member. The non-conductive member can surround and support the guide member on a wire guide body or, in the alternative, may be separate from the support member.

Abstract: A digital method of testing a wire drawing distance to determine the percent wire elongation provided thereby in which a predetermined test length of wire is pulled through the die and then around a rotatable capstan thereby rotating the same. A train of electrical pulses is generated in response to rotational movement of the capstan, there being 10.sup.n pulses generated in response to the rotational movement of the capstan caused by pulling a length of drawn wire therearound equal in length to the test length prior to drawing through the die where "n" is a positive integer greater than zero and less than five. The pulses generated during the pulling of the test length of the wire through the die are counted, and a visual indication of the pulse count with the most significant digit eliminated is provided.

Abstract: A metal casing is provided having flat, parallel front and back sides. A first cylindrical cavity having a bottom wall is formed in the front casing side. A cylindrical metal plug having top and bottom ends is secured by heat shrinking in the first casing cavity, the bottom end having a second, concentric cylindrical cavity formed therein and engaging the bottom wall of the cavity. A cylindrical metal blank having opposite ends and a concentric core formed of a synthetic hard, wear-resistant material, such as polycrystalline aggregate of synthetic or natural diamond or polycrystalline cubic boron nitride, is secured in the second cavity by heat shrinking with one end engaging the bottom thereof and the other end engaging the first casing cavity bottom wall.

Abstract: A wire drawing die includes a metal casing having flat, parallel front and back sides. A first cylindrical cavity having a bottom wall is formed in the front casing side. A cylindrical metal plug having top and bottom ends is secured in the first casing cavity, the bottom end having a second, concentric cylindrical cavity formed therein. A cylindrical metal blank having opposite ends and a concentric core formed of a synthetic hard, wear-resistant material, such as polycrystalline aggregate of synthetic diamond or polycrystalline cubic boron nitride, is closely fitted in the second cavity with one end engaging the bottom thereof and the other end engaging the first casing cavity bottom wall. The top end of the plug and the back side of the casing have concentric countersunk openings therein respectively extending therethrough to the core, and the core has a concentric die opening therethrough communicating between the countersunk openings.