A subterranean support-bolt drill bit has a bit body rotatable about a central axis, the bit body having a forward end and a rearward end axially spaced away from the forward end. The support-bolt drill bit includes at least one bit cutting element coupled to the bit body, the at least one bit cutting element including a cutting edge. The support-bolt drill bit also includes a central pilot projecting from the bit body beyond the at least one bit cutting element in an axially forward direction, the central pilot including a pilot cutting edge.

The invention relates to a carbide insert (2) for a rock drill (1), which is configured as a non-percussively operating twist drill with a cylindrical drill body (11) and a working end (13) having the carbide insert (2), the carbide insert (2) having two cutting lips (22) which are radially opposite one another relative to an axis of drill rotation (d) and are arranged at an angle to one another to form a centering tip (21) and with each of which a peripheral conveyor spiral (14) may be associated. To be able to introduce a drilled hole more quickly, easily and simply and with less risk of damage into a workpiece of rock, rock-like material, hard plastics, glass or the like, it is proposed that the cutting lips (22) be configured asymmetrically to one another, wherein at least one of the cutting lips (22) defines over its radial profile, in a central region spaced from its radial ends, a tip (23) projecting in the drilling direction (b).

A roof-bolt drill bit includes a bit body that is rotatable about a central axis, a coupling pocket defined in the bit body, and at least one cutting element mounted to the bit body. The at least one cutting element includes a cutting face, a cutting edge adjacent the cutting face, a back surface opposite the cutting face, and a side surface extending between the cutting edge and the back surface. The roof-bolt drill bit additionally includes a coupling attachment coupled to the bit body, the coupling attachment being positioned adjacent to a portion of the side surface of the cutting element that abuts a side surface of the coupling pocket.

A roof-bolt drill bit includes a bit body that is rotatable about a central axis, a coupling pocket defined in the bit body, and at least one cutting element mounted to the bit body. The at least one cutting element includes a cutting face, a cutting edge adjacent the cutting face, a back surface opposite the cutting face, and a side surface extending between the cutting edge and the back surface. The roof-bolt drill bit additionally includes a coupling attachment coupled to the bit body, the coupling attachment being positioned adjacent to a portion of the side surface of the cutting element that abuts a side surface of the coupling pocket.

A drill bit includes a tool body having a main body in the form of a cylinder. A chip removing structure is provided on the main body. The tool body has a distal end provided with a clamping slot and a cutter inlaid in the clamping slot. The cutter has at least two blade portions arranged circumferentially on the distal end of the tool body and extending radially relative to the tool body. Each of the blade portions has a front side along the drill bit's rotating direction and a back side against the rotating direction. The clamping slot covers the back side of one blade portion by an area larger than that used to cover the front side of the same blade portion.

A drill bit includes a tool body having a main body in the form of a cylinder. A chip removing structure is provided on the main body. The tool body has a distal end provided with a clamping slot and a cutter inlaid in the clamping slot. The cutter has at least two blade portions arranged circumferentially on the distal end of the tool body and extending radially relative to the tool body. Each of the blade portions has a front side along the drill bit's rotating direction and a back side against the rotating direction. The clamping slot covers the back side of one blade portion by an area larger than that used to cover the front side of the same blade portion.

The invention concerns a cutting tip (6) comprising: a core (10) that extends axially; and at least a first branch (12) and a second branch (14) that extend radially from the core (10), each comprising: a proximal portion (12a, 14a) connected to the core (10), a distal portion (12b, 14b), and a central portion (12c, 14c) connecting the proximal portion (12a, 14a) and the distal portion (12b, 14b); and a cutting edge (12d, 14d) extending at least along the distal portion (12b, 14b) and the central portion (12c, 14c); in which: the distal portion (12b) of the first branch (12) is arranged radially forward relative to the central portion (12c) of the first branch (12); and the central portion (14c) of the second branch (14) is arranged radially forward relative to the distal portion (14b) of the second branch (14).

The invention concerns a cutting tip (6) comprising: a core (10) that extends axially; and at least a first branch (12) and a second branch (14) that extend radially from the core (10), each comprising: a proximal portion (12a, 14a) connected to the core (10), a distal portion (12b, 14b), and a central portion (12c, 14c) connecting the proximal portion (12a, 14a) and the distal portion (12b, 14b); and a cutting edge (12d, 14d) extending at least along the distal portion (12b, 14b) and the central portion (12c, 14c); in which: the distal portion (12b) of the first branch (12) is arranged radially forward relative to the central portion (12c) of the first branch (12); and the central portion (14c) of the second branch (14) is arranged radially forward relative to the distal portion (14b) of the second branch (14).

A cutter element for rock removal comprises a free standing PCD body (801, 1801) comprising one or more physical volumes (1702, 1703), the PCD material being invariant in terms of the diamond and metal network compositional ratio and metal elemental composition such that each physical volume does not differ to any other physical volume with respect to diamond and metal network compositional ratio and metal elemental composition. The PCD body has a functional working volume (803) forming in use the region which comes into contact with the rock. A functional support volume (804) extant in use and having a proximal free surface extends from the functional working volume. The PCD body has an aspect ratio such that the ratio of the length (ae) of the longest edge of the circumscribing rectangular parallelepiped of the overall PCD body to the largest width (ad) of the smallest rectangular face from which the functional working volume extends of the circumscribing rectangular parallelepiped, is greater than or equal to 1.0.

A cutter element for rock removal comprises a free standing PCD body (801, 1801) comprising one or more physical volumes (1702, 1703), the PCD material being invariant in terms of the diamond and metal network compositional ratio and metal elemental composition such that each physical volume does not differ to any other physical volume with respect to diamond and metal network compositional ratio and metal elemental composition. The PCD body has a functional working volume (803) forming in use the region which comes into contact with the rock. A functional support volume (804) extant in use and having a proximal free surface extends from the functional working volume. The PCD body has an aspect ratio such that the ratio of the length (ae) of the longest edge of the circumscribing rectangular parallelepiped of the overall PCD body to the largest width (ad) of the smallest rectangular face from which the functional working volume extends of the circumscribing rectangular parallelepiped, is greater than or equal to 1.0.