Abstract: A rotatable cutting tool for use in impinging earth strata includes a cutting tool body having a central longitudinal axis, the cutting tool body including a head portion, a shank portion axially rearward of the head portion and a hard cutting tip affixed to the head portion of the cutting tool body. The head portion includes a first head section adjacent to an axial forward end of the head portion, wherein the first head section includes a plurality of first side faces such that adjacent first side faces meet to form a corresponding plurality of first common edges. The head portion further includes a second head section adjacent to an axial rearward end of the head portion, the second head section having a plurality of second side faces wherein adjacent second side faces meet to form a corresponding plurality of second common edges.

Abstract: A rotatable cutting tool that is useful for impingement upon a substrate and is adapted to be rotatably retained within the bore of a holder. The rotatable cutting tool includes an elongate cutting tool body, which has an axial forward end and an axial rearward end, as well as a socket at the axial forward end thereof. The rotatable cutting tool also includes a hard cutting member that is affixed to the cutting tool body within the socket. The hard cutting member has an axial forward end and an axial rearward end. The hard cutting member has a superhard axial forward portion at the axial forward end thereof wherein the superhard axial forward portion has a maximum transverse dimension. The hard cutting member further has a hard axial rearward portion contiguous with and axial rearward of the superhard axial forward portion. The hard axial rearward portion has a maximum transverse dimension.

Abstract: A rotatable cutting tool that is for impingement upon a substrate and adapted to be rotatably retained within the bore of a holder. The rotatable cutting tool includes an elongate cutting tool body, which has an axial forward end and an axial rearward end with a socket at the axial forward end thereof. The rotatable cutting tool further has a hard cutting member, which is affixed to the cutting tool body within the socket. The hard cutting member has an axial forward end and an axial rearward end. The hard cutting member has an axial forward functional portion which has a starting transverse functional dimension, and further has a base portion which has a maximum transverse base dimension. There is a ratio of the starting transverse functional dimension to the maximum transverse base dimension ranging between equal to 0.42 and less than 0.48.

Abstract: A rotatable cutting tool that is useful for impingement upon a substrate and is adapted to be rotatably retained within the bore of a holder. The rotatable cutting tool includes an elongate cutting tool body, which has an axial forward end and an axial rearward end, as well as a socket at the axial forward end thereof. The rotatable cutting tool also includes a hard cutting member that is affixed to the cutting tool body within the socket. The hard cutting member has an axial forward end and an axial rearward end. The hard cutting member has a superhard axial forward portion at the axial forward end thereof wherein the superhard axial forward portion has a maximum transverse dimension. The hard cutting member further has a hard axial rearward portion contiguous with and axial rearward of the superhard axial forward portion. The hard axial rearward portion has a maximum transverse dimension.

Abstract: A rotatable cutting tool carried in a bore of a holder wherein the holder has a forward surface surrounding a forward end of the bore. The rotatable cutting tool includes an elongate cutting tool body that has a central longitudinal axis, an axial forward end and an axial rearward end. The cutting tool body contains a socket in the axial forward end thereof whereby the socket receives a hard insert therein. The cutting tool body has an enlarged diameter collar mediate of the axial forward end and the axial rearward end. The mediate collar presents an axial forward facing surface and an axial rearward facing surface. The cutting tool body has an axial forward hardness region beginning at and extending a first pre-selected distance in an axial rearward direction from the axial forward end to encompass the axial forward facing surface of the collar. The axial forward hardness region has a hardness equal to or greater than a first hardness, as well as a first average hardness.

Abstract: A rotatable cutting tool includes a cutting tool body that has an axial forward end and an axial rearward end. The cutting tool body further has an axial length. There is a hard tip, which has a distal end, affixed to the cutting tool body at the axial forward end thereof. The cutting tool body has a clearance portion axial rearward of the distal end of the hard tip wherein the clearance portion has a transverse dimension. The clearance portion includes an axial forward transverse dimension and a minimum transverse dimension that is axial rearward of the axial forward transverse dimension. The axial forward dimension is greater than the minimum transverse dimension. The clearance portion has an axial length equal to between about ten percent and about thirty-five percent of the axial length of the cutting tool body.

Abstract: A cutting tool assembly including a cutting bit having a head and a cylindrical shank portion of substantially constant diameter depending from the head as well as a bit holder including a cylindrical bore for receiving the cylindrical shank portion of the cutting bit. The shank portion includes an annular recessed groove. The cutting tool assembly further includes a retainer sleeve disposed between the shank portion of the cutting bit and the bore of the bit holder and which closely conforms about the shank portion while allowing the shank portion to rotate within the bore. The retainer sleeve includes at least one inwardly folded over stop tab that cooperates with the recessed groove to axially position the shank within the retainer. The retainer includes stop tabs that are bent around beyond the shear cut lines of the tab opening so that the hub portions of the shank do not transmit a force against these weakened shear cut areas of the retainer.

Abstract: A cutting tool body includes a net-shaped steel body that has an axial forward end and an axial rearward end. The net-shaped steel body contains at the axial forward end thereof a cold-headed socket. The net-shaped steel body further contains a cold-headed puller groove axial rearward of the cold-headed socket.

Abstract: A rotatable cutting tool carried in a bore of a holder wherein the holder has a forward surface surrounding a forward end of the bore. The rotatable cutting tool includes an elongate cutting tool body that has a central longitudinal axis, an axial forward end and an axial rearward end. The cutting tool body contains a socket in the axial forward end thereof whereby the socket receives a hard insert therein. The cutting tool body has an enlarged diameter collar mediate of the axial forward end and the axial rearward end. The mediate collar presents an axial forward facing surface and an axial rearward facing surface. The cutting tool body has an axial forward hardness region beginning at and extending a first pre-selected distance in an axial rearward direction from the axial forward end to encompass the axial forward facing surface of the collar. The axial forward hardness region has a hardness equal to or greater than a first hardness, as well as a first average hardness.

Abstract: An assembly that includes a rotatable cutting tool and a tool holder. The rotatable cutting tool has an integral enlarged dimension portion mediate which has a periphery and a rearwardly facing surface which defines a generally planar shoulder. The tool holder includes a bore and has an integral mating surface which surrounds the forward end of the bore. The mating surface has a peripheral edge. The rotatable cutting tool is rotatably retained in the bore of the tool holder body so that the shoulder of the elongate cutting tool body contacts the mating surface of the tool holder body and the periphery of the enlarged dimension portion of the elongate cutting tool body extends radially outwardly past the peripheral edge of the mating surface.

Abstract: A cutting tool assembly including a cutting bit having a head and a cylindrical shank portion of substantially constant diameter depending from the head as well as a bit holder including a cylindrical bore for receiving the cylindrical shank portion of the cutting bit. The shank portion includes an annular recessed groove. The cutting tool assembly further includes a retainer sleeve disposed between the shank portion of the cutting bit and the bore of the bit holder and which closely conforms about the shank portion while allowing the shank portion to rotate within the bore. The retainer sleeve includes at least one inwardly folded over stop tab that cooperates with the recessed groove to axially position the shank within the retainer. The retainer includes stop tabs that are bent around beyond the shear cut lines of the tab opening so that the hub portions of the shank do not transmit a force against these weakened shear cut areas of the retainer.

Abstract: A rotatable cutting tool for impinging the earth strata wherein the cutting tool has a tool body with an axial forward end and an axial rearward end. A hard insert is at the axial forward end and a retainer is carried by a shank portion near the axial rearward end. The hard insert has an axial forward generally conical tip section that presents a tip surface and has a starting included angle of between greater than about 110 degrees and less than about 140 degrees, a transition section (wherein at least a portion of the transition section presenting a convex shape) that is contiguous with and axially rearward of the tip section, a radially outwardly expanding first mediate section that is axially rearward of the convex section, and a base section that is axially rearward of the mediate section.

Abstract: A bit holder block is provided composed of a foot portion for being received in a seat of a rotary member and a bit holder portion for releasably holding a cutter bit with respect to a bit bore therein. The bit bore has a forward opening at a bit abutment face of the bit holder block. The cutter bit is provided with an annular abutment surface for abutting the bit abutment face. A bit retainer port is provided in the bit holder block located at, and communicates with, a rear opening of the bit bore for therein securing a retainer clip to an annular groove in the cutter bit. A rear segment of the bit holder block provides a strong reinforcing structure for the area around the rear opening of the bit bore which counters a fulcrum force generated at the rear opening of the bit bore, the fulcrum force arising during operation due to a resultant force acting on the cutter bit being directed below the axis of the cutter bit, rather than above it, as was previously believed in the art.

Abstract: A cutting tool assembly including a cutting bit having a head and a cylindrical shank portion of substantially constant diameter depending from the head as well as a bit holder including a cylindrical bore for receiving the cylindrical shank portion of the cutting bit. The shank portion includes an annular recessed groove, the cylindrical bore includes a notch corresponding to and disposed opposite the annular recessed groove. The cutting tool assembly further includes a retainer sleeve disposed between the shank portion of the cutting bit and the bore of the bit holder and which closely conforms about the shank portion while allowing the shank portion to rotate within the bore.

Abstract: A bit holder for a cutting tool utilizes a non-rotatable sleeve which is slit its entire length axially and is force-fitted into the bore of the bit holder. The sleeve is removable in the field and provides protection for the bit holder. In an alternate embodiment the sleeve is provided with additional retaining means in the form of a circumferential flange which extends beyond the bit holder and contacts the rearmost portion thereof.

Abstract: A deformed sleeve for mounting a cutting tool in a bit holder has one end shaped as an ellipse. The deformation is done by the application of pressure before heat treating. No further machining is necessary after the heat treatment. The deformed sleeve is force-fitted into a bore in a bit holder and is retained therein in a non-rotating manner by friction.

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 rotatable cutting tool of the type having a bored tool holder, a cutting bit comprising a shank depending from a head portion with first forward and second rearward retaining portions spaced by a recessed intermediate section includes a cylindrical split sleeve member which extends from said forward retaining portion to said rearward portion to both abut and protect the exposed peripheries of the retaining portions from wear while permitting free rotation of the tool bit within the tool holder.

Abstract: A mine tool roof bit insert having a leading face inclined at a constant angle of 0.degree.-3.degree. with respect to the axis of rotation, and a frontal face with a variable relief angle decreasing with increasing radial distance from the axis from 25.degree.-55.degree. at the axis to 15.degree.-25.degree. at its radially distal edge, the rate of decrease being at least 10.degree./in. A method of drilling a hole in a mine roof involves positioning a mine tool including the variable rake bit, insert, or the like, and rotating the bit, insert or the like at about 250-600 rpm and about 1000-8000 lb thrust for a time sufficient to drill the hole in the mine roof.