Abstract: A method of determining feed and radial forces has the steps of subdividing work materials into seven groups which are different from one another by Brinell hardness, for each group separately determining a feed force and radial force based on a tangential force in accordance with individual formula which is different from formulas for other groups, and also separately for a turning process and for a boring process. Also, a calculator is proposed which utilizes the inventive method.

Abstract: A method of determining feed and radial forces has the steps of subdividing work materials into seven groups which are different from one another by Brinell hardness, for each group separately determining a feed force and radial force based on a tangential force in accordance with individual formula which is different from formulas for other groups, and also separately for a turning process and for a boring process. Also, a calculator is proposed which utilizes the inventive method.

Abstract: An indexable cutting insert for use with a cutting tool includes an insert body having a first surface and a side relief surface defining a cutting edge adjacent the intersection of the first surface and the side relief surface. A chip breaking structure is interposed between the first surface and the cutting edge. The chip breaking structure includes first and second series of wedges. Each series of wedges is disposed inwardly from the cutting edge and the wedge series are disposed in orthogonal or normal relation to one another. In a preferred arrangement, the narrow edges of the first and second series of wedges are aligned with one another.

Abstract: A tamping pad includes cutout along the length of the leading edge thereof to support at least one wear-resistant insert rigidly positioned therein. The wear-resistant insert comprises a body having a first side and a second opposed side, first and second opposed major surfaces and first and second opposed shoulders. The first side of the insert body defines a tamping blade leading edge which is arcuate in shape between the opposed shoulders. The arcuate leading edge of the insert body has a radius which defines the length of the arcuate edge to be of a ratio of about 1.3 relative to the width of the carbide insert. Preferably, the plurality of inserts extends end to end along the length of the leading edge of the blade to define the interrupted leading edge of the tamping pad as formed by the curvilinear leading edge of each of the plurality of inserts.

Abstract: A grader blade has a steel body with a bottom edge incorporating a pair of tiered, elongated carbide inserts in a forward portion thereof. The carbide inserts, being arranged in a tiered contacting relationship, are disposed in a stepped recess formed in and along the forward portion of the bottom edge of the blade body and brazed to the blade body and to each other so as to project forwardly and downwardly from the recess. A front one of the tiered inserts is composed of a cemented carbide composition having a high cobalt content, for instance 20 percent by weight, adapting it for enhanced impact wear resistance, whereas a rear one of the tiered inserts is composed of a cemented carbide composition having a low cobalt content, for instance 11.5 percent by weight, adapting it for enhanced downpressure wear resistance.

Abstract: A rotary percussion rock drill bit has a body and a symmetrical cross-like arrangement of crushing and cutting inserts secured on the body. The bit body has a rearward shank portion and a forward boring head portion with a front face. The cylindrical crushing inserts are secured in the forward head portion and have noncutting hemispherical rock crushing ends exposed at the front face of the head portion. The cutting inserts, which can be rectangular or cylindrical in shape, are secured in the forward head portion and have roof-shaped ends exposed at the front face of the head portion. A peak of each roof-shaped end defines a rock cutting edge. The crushing and cutting inserts are arranged on the head portion with their respective hemispherical and roof-shaped ends in a symmetrical cross-like pattern. The bit body also has a longitudinal central axis, and the crushing and cutting inserts are aligned along planes disposed in orthogonal relation to one another and intersecting at the central axis.

Abstract: A grader blade has a steel body with a bottom edge incorporating a substrate of air-hardened tool steel casting material assembling a preformed cemented carbide insert in tiered relationship with, and rearwardly of, a casted layer of carbide grit. The front casted carbide grit layer is formed in the casting operation and the rear preformed cemented carbide insert is arranged in the tiered contacting and attached relationship with the carbide grit layer as the latter is casted with the substrate of special steel casting that holds the insert and layer together. The steel body of the blade also includes a recess formed in and along the forward portion of the blade bottom edge into which the casted asembly is disposed and welded to the blade.

Abstract: Disclosed according to the present invention is a two-prong rotary drill bit, especially for use with roof drills. The two-prong bit has a supporting body having an axis of rotation. The two-prong bit has a pair of inserts, one insert on each of the prongs. Each of the inserts has a cutting portion facing in the direction of rotation and a mounting portion. When viewed in a direction parallel to the axis of rotation, each of the inserts will have a cross sectional configuration which is generally wedge-shaped. Also disclosed are wedge-shaped inserts especially for use with roof drill bits.