Improved drill collars and their manufacture include the assembly of a body member formed of an appropriate high strength material, and a liner within the body. The body member will provide the majority of the strength and weight required of the drill collar, while the liner will be constructed of a material offering improved resistance to corrosion and stress corrosion cracking. The liner may be formed of a metal alloy, and may be retained within the body member by deforming the liner radially ...

A drill, especially a masonry and rock drill, in which a fluted shank has a ransverse slot in the working end and a hard cutting plate seated in the slot and retained therein by a pin removably mounted in the shank. The cutting plate may be indexable in the slot to expose respective regions thereof for cutting operations. The cutting plate engages the bottom of the slot and is supported thereby. The engagement of the cutting plate by the bottom and side walls of the slot and by the pin holds the...

The invention contemplates a miniature drill which is hand-held at a quill or sleeve on the drill axis, in the manner of a pencil or pen. The tool includes mass eccentric to the drill axis for absorbing reaction torque occasioned by drill operation. In one employment, the fingers of the hand which holds the sleeve also steady the drill against the workpiece, and in another employment a work-supporting jig fastened to the sleeve converts the tool into a portable miniature drill press, assuring ac...

A drill bit for drilling into underground formations is disclosed, the drill bit having conduits for providing either lubricant or gaseous drilling fluid to the cutting cone bearings. In an alternate mode of operation, a mixture of lubricant and gaseous fluid is supplied to the bearings.

A drilling apparatus for the preparation of bone cavities includes a plurality of drills which are simultaneously driven in opposite direction with the cutting surfaces of each drill overlapping the cutting surfaces of at least one other drill to provide intersecting bone cavities. The drills may be driven by gearing located within the drill head or by gearing located in an attachment suitable for connection to a conventional drill head having a single output drive. The drills may be disposed al...

A drill tool is provided with: a drive source accommodated in a tool body 2; a bit drive shaft 3 which is rotation-driven by the drive source and provided projectingly from a front end of the drill body 2; and a diamond bit 4 attached to a front end of the bit drive shaft 3. Further, the drill tool is provided with a vibrating apparatus which generates vibrating force which acts in the axial direction of the bit drive shaft 3, a magnitude of which pulsates, and vibrating moment which acts in the...

A rock drill (1) for rotary hammers or the like is proposed in which a conveying helix (3) having main and secondary webs (6 to 9) is used. In this case, the convexing helix (3) is run up to the front region of the drill head (2) with the core cross section being increased or the flute depth being decreased.

An object of the present invention is to provide a drill bit capable of easily drilling a drill hole that has no rifling, and has high circularity, can be easily positioned, the drill bit comprising a cutting blade tip which is composed of a block body of cemented carbide, three cutting blade portions are formed circumferentially equidistantly around the cutting blade tip, a connection line between a cutting surface 5 and a flank surface 6, said cutting and flank surfaces being formed in each sa...

A drill for producing close tolerance holes in non-ferrous and non-metallic composite materials in which the essentially cylindrical size of the body of the drill is maintained all the way to the drilling point, the cylindrical shape as it approaches the drilling point is tapered by being flattened off on opposite sides to taper the body, and the drilling point has symmetrically formed and angularly related cutting edges in the opposite edges of the flattened and tapered body. The drill having t...

A stone or masonry drill having a shank with at least one spiral groove commencing at one end and a transverse slot in the one end in which a hard wear resistant blade forming a cutting element is fixed, as by soldering. The blade extends through the web portion of the shank and preferably has the opposite ends disposed at the forwardly facing side of the rib between adjacent convolutions of the groove. The diameter of the one end of the shank falls within the cylindrical envelope of the shank.