Abstract: A tool bit for use in at least one of a drilling and cutting operation is formed of an axially extending carrier member (1) and a cutting member (2). The cutting member (2) has an expansion joint (2a) extending parallel to the axis of the carrier member (1). The expansion joint (2a) is formed by reducing the thickness of the cutting member (2) so that material webs (2b) remain. In the fabrication and formation of the tool bit, the cutting member (2) is a single unit. In the use of the tool bit, due to the expansion joint the cutting member forms individual operating units (2a) affording reduced material expense of the cutting member (2), because of reduced stresses.

Abstract: A masonry drill and method of manufacture is disclosed. The drill has an elongated axial body with at least one discharge groove and a transverse slot located at one end with a hardened drill bit insert brazed within the slot. The hardened insert has projections extending outward from flat planar surfaces which hold the insert in proper orientation within the axial drill body so that it may be brazed into place subsequent to insertion into the drill body.

Abstract: A fixed cutter drill bit includes sets of cutter elements mounted on the bit face. Each set includes at least two cutters mounted on different blades at generally the same radial position with reset to the bit axis but having differing degrees of backrake. The cutter elements of a set may be mounted having their cutting faces out-of-profile, such that certain elements in the set are exposed to the formation material to a greater extent than other cutter elements in the same set. The cutter elements in a set may have cutting faces and profiles that are identical, or they may vary in size or shape or both. The bit exhibits increased stability and provides substantial improvement in ROP without requiting excessive WOB.

Abstract: A cutting structure for use in a rotary drag bit for downhole drilling is disclosed which relieves stress concentrations focused in the cutting structure along a line adjacent the surface where a cutting element abuts the carrier element or stud. A semicircular polycrystalline diamond compact (PDC) cutting element segment and a cooperating blank segment are diametrically bonded together and, in turn, bonded to a surface on the carrier element. The PDC segment has a chamfer formed along one inner edge, and the blank segment similarly has a chamfer formed along one inner edge. The two segments are joined together along their chamfered edges so that the chamfers are aligned to form a channel through the cutting structure when the segments are bonded to the carrier element. A groove may also be formed in the carrier element along the line where the polycrystalline diamond cutting element, the blank segment and the carrier element are joined, either in addition to or in lieu of the chamfers.

Abstract: The forward surface of a bit mount against which the shoulder of a cutting bit can rotatably bear has carbide inserts brazed therein to reduce wear of the forward surface. In the manufacture thereof, there are insert holes in the forward surface into which the carbide inserts are inserted. There are smaller holes next to the insert holes, and overlapping therewith, into which braze slugs are inserted. There is an interference fit between the carbide inserts and the braze slugs, which aids in retaining the carbide inserts in the insert holes during the brazing operation.

Abstract: A fixed cutter drill bit includes a plurality of angularly spaced radial wings each with a row of cutting elements mounted thereon and protruding from the bit for drilling through formation material. On a first of the wings, a first row of the cutting elements has alternately larger and smaller area cutting faces at spaced selected radial positions relative to the center of the bit. Similarly, a second row of cutting elements is mounted on a second of the wings at substantially the same radial positions but with the radial positions of the larger and smaller cutting faces reversed over those on the first wing. A third wing includes a third row of cutting elements with cutting faces of intermediate area located at each of the selected radial positions. The combination of different sizes of cutting elements at each radial position defines a set having a profile with the intermediate and smaller cutting elements located entirely within the larger cutting element.

Abstract: A modular drill bit mounts legs within recesses in a body which are parallel to the central axis of the body using threaded studs with tapered outer portions, in conjunction with an attached pin having recesses therein receiving the upper ends of the legs. The lower ends of the legs terminate in spindles of open face configuration rotatably receiving cones thereon for rotation via a arrangement of bushings, roller bearings and thrust bearings, and a plurality of seals which slide and therefore rotate relative to both the leg spindle and the cone with the help of pressure compensating apparatus. Each cone is provided with cutting teeth which are inclined in the direction of cone rotation and which cover the cone surface in a manner which provides scraping of substantially the entire bottom surface of the hole being drilled and in a manner providing efficient scraping and crushing action.

Abstract: Precipitation hardenable solders are used for securing hard metal or hard material parts to the support member of a tool for drilling, chipping or cutting rock or hard construction materials. The support member is formed of steel. The hard metal or hard material parts are secured to the support member by soldering using a precipitation hardenable solder. The parts secured to the support member are subjected after a solution treatment to the tempering and precipitation hardening temperature.

Abstract: A cemented carbide tip for a cutter bit is provided. The tip is rotationally symmetric about its longitudinal axis and has a socket in its rear end for brazine to a steel protrusion on a steel tool shank. A surface of the socket has bumps thereon to maintain a substantially uniform braze joint thickness.