Abstract: A tool element for cutting a workpiece includes a body including a shank for connecting the tool element to a power tool, a first cutting portion formed as part of the body and defining a first removing pattern, and a cutting element removably coupled to the body and including a second cutting portion defining a second removing pattern, the second removing pattern being a substantial continuation of the first removing pattern.

Abstract: An auger bit includes a shaft having a central axis, a cutting insert mounted to said shaft, and a feed screw that is separate from the cutting insert and which is mounted to the shaft. The cutting insert and the feed screw are engaged with each other. A single locking member, such as a set screw, secures the feed screw member to the shaft, and thereby secures the cutting insert to the shaft. If the feed screw or the cutting insert become worn, feed screw or the cutting insert can be replaced.

Abstract: A metal cutting tool has a cutting head releasably mounted on a front end of a tool shank, in a self-clamping manner. The tool shank's forward end is provided with a pair of shank coupling portions, each having a forwardly facing shank support surface. A pocket recess is defined between the shank's coupling portions. Within the pocket recess are a plurality of shank fixation surfaces which are parallel to a longitudinal axis of the tool shank. The cutting head has a cap portion and a fixation portion extending in rearward direction therefrom. The cap portion includes a pair of head segments, each having a rearwardly facing head base surface. The cutting head's fixation portion has a plurality of head fixation surfaces which are parallel to a longitudinal axis of the cutting head.

Abstract: Tool holder assembly (TH) for multifunctional machining, such as drilling, boring, facing, and turning, eliminate interference between facing and turning, and secure an adequate chip groove space (10) for discharging chips therethrough without deterioration of a rigidity of the tool holder (TH), thereby securing a good quality of machining, and an exclusive adapter (TA) suitable to the foregoing tool holder (TH) assembly for multifunctional machining.

Abstract: An indexable type cutting tool includes a drill having a shank and a drill body which extends from the shank, the drill body being defined with body flutes, and being formed with an insert seat which has seat side surfaces and a seat bottom surface and body flank surfaces and body thinning surfaces; a drill insert fitted into the insert seat of the drill body, having cutting edges and an insert bottom surface which is brought into close contact with the seat bottom surface, formed with insert flutes and insert side surfaces which are brought into close contact with the seat side surfaces, and defined with a through-hole which passes through the insert side surfaces; and a fastening screw for fastening the drill insert fitted into the insert seat to the drill.

Abstract: A ring with a cutting edge detachably fixed to a drilling tool, and machines the peripheral edge of a hole bored by the drilling tool can be simply attached to the drilling tool.

Abstract: A rotary cutting tool having a longitudinal axis defining forward and rearward directions and a direction of rotation, includes a cutting head releasably mounted to a front end of a tool shank. The cutting head includes a cap portion and a rearwardly extending tail portion. The cap portion is provided with a plurality of head segments, each head segment having a rotationally leading end facing the direction of rotation and a rotationally trailing end. The trailing end of each head segment is provided with a locking member which extends in a direction opposite the direction of rotation. The tool shank has a forward end provided with a corresponding plurality of locking recesses opening out to the direction of rotation, and a shank pocket recess. In the assembled tool, the tail portion of the cutting head is received into the shank pocket recess and each of the plurality of locking members is received into a corresponding locking recess.

Abstract: A cutting tool insert and holder therefore, the drill insert having a helical geometry corresponding to helical flutes in a drill body holder which enable the drill tool assembly to more efficiently remove chips from a hole during operation, the drill insert comprising a drill insert body having a first end opposite a second end, a plurality of helical flutes formed in the drill insert body, a plurality of cutting edges formed at the interfaces of the plurality of helical flutes and the first end of the drill insert body, and an aperture formed in each helical flute.

Abstract: The present invention provides a new drilling tool useful in machining hydraulic port seals for fluid power ports. The drilling tool drills the port hole to size in a solid material for the minor thread diameter in combination with forming the port in a single operation. The drilling tool has a tool holder having a rotational axis, a first drilling insert having cutting surfaces on a first side and a mounting surface on a second side, at least one second drilling insert having a predetermined cutting surface portion and a mounting portion which is mounted on the holder at a location from the rotational axis of the holder. The at least one second drilling insert has first and second portions which engage and machine a work piece in a drilling operation to form a spot face and a seal form.

Abstract: Tool elements, such as, bits, auger bits, concrete bits, etc. are provided. The tool elements include a body and a cutting element removably connected to the body. The cutting element may be removably connected to the body in a variety of manners. The body and the cutting element may be made from a similar material or from different materials. The tool element may also include a second cutting element removably connected to the body or to the first cutting element. In some aspects, the second cutting element is a feed screw. In other aspects, the second cutting element is a continuation of the first cutting element.

Abstract: A short-hole drill, including a drill body being rotatable about a center axis and having a rotationally symmetrical envelope surface, one or more replaceable cutting inserts mounted in pockets in a front end of the drill body, one or more outwardly open flutes being countersunk in the envelope surface and extending rearwardly from the front end of the drill body to evacuate chips from the cutting inserts, and a number of replaceable first support pads being mounted in countersunk seats proximate the front end of the drill body to support and guide the drill against a hole wall generated by the cutting inserts. A number of second support pads are mounted in countersunk seats that are axially spaced apart from the first support pads by an envelope surface portion having a predetermined axial extension to support and guide the drill when the first support pads leave the hole wall.

Abstract: A rotary cutting tool that is composed of a tool shank with at least one chucking groove or chip flute and one exchangeable cutting insert. At the tip of the shank a recess for accommodating the cutting insert is provided. The tool shank, on its circumference, has a limb with a bearing surface that is inclined relative to the tool axis and that corresponds to a likewise inclined bearing surface on a wing of the cutting insert. The inclination of the bearing surfaces produces an axial force that retains the cutting insert on the tool shank. The abstract of the disclosure is submitted herewith as required by 37 C.F.R. §1.72(b). As stated in 37 C.F.R. §1.72(b): A brief abstract of the technical disclosure in the specification must commence on a separate sheet, preferably following the claims, under the heading “Abstract of the Disclosure.

Abstract: A drilling tool cuffing insert adapted to be clamped in a rotatably driven drilling tool base body, the base body having a mounting groove formed in an end thereof defined by a pair of clamping jaws, each of the jaws having a bore therethrough, one of the bores being threaded, the bores for receiving a mounting screw for clamping said cuffing insert in the mounting groove, each of the jaws having a centering face, the cuffing insert comprising a plate-shaped cuffing element having a first end, a second opposite end, and a bore therethrough for receiving the mounting screw, the first end of the cuffing element having a pair of mutually opposing cuffing edges, the element having a chip face extending from each cuffing edge to the second end of the element, each of the chip faces having a centering fin with a centering face thereon, the cuffing element centering faces adapted to engage with the centering faces on the jaws of the base body to center the cuffing insert in the base body.

Abstract: A replaceable drill tip and drill shank combination has a serrated and dowel pinned drill tip and drill shank interface, wherein the drill tip has a serrated bottom surface and a channel for receiving a dowel pin which extends axially from a drill shank, the drill shank having a serrated distal end which engages with the serrations in the bottom surface of the drill tip, and fasteners which extend through the drill tip into the drill shank.

Abstract: A solid drill bit for machine tools has a drill bit body and two indexable inserts arranged at a radial distance from one another in respective insert seats. The inserts have an essentially quadratic contour. Their front-end main cutting edges project axially beyond the drill bit body and radially overlap one another. The outer insert has an outer insert corner and a secondary cutting edge perpendicular to the main cutting edge that projects radially beyond the circumference of the drill bit body. To permit burr-free through-drilling, the main cutting edge of the outer insert is subdivided in its longitudinal extent into a radially inner working section and a rectilinear peeling section adjoining the working section and extending to the outer insert corner. The sections enclose a setting angle of 95° to 120°. The peeling section is set at a positive setting angle of 72° to 87°.

Abstract: A drill for chip removing machining, including a drill body, and a replaceable cutting insert mounted in a pocket formed in a front tip of the drill body. A chip flute extends backwardly from the pocket along the drill body, and the cutting insert is fixed in the pocket by a screw including a head and a shank having a male thread. The cutting insert includes a through hole extending between a topside and an underside. The hole has a basic shape that is rotationally symmetrical in relation to a center axis, and is delimited by a series of surfaces including a mouth surface, converging downward from the topside, and a shoulder surface. The head of the screw is kept pressed against the shoulder surface when the male thread of the screw is tightened in a female thread included in a hole that mouths in a bottom of the pocket. The mouth surface in the hole of the cutting insert has a trumpet-like, cross section-wise convex shape adjacent to the topside of the cutting insert.

Abstract: A blade for a cutting tool. The cutting tool can be supportable on a spindle of a power tool. The blade can include a blade body removably supportable on the cutting tool and being moveable with the cutting tool relative to the power tool for cutting a workpiece. The blade can further include a first cutting edge extending outwardly from the blade body and a second cutting edge extending outwardly from the blade body. When the blade is supported in the cutting tool, the first cutting edge can extend radially across an end of the cutting tool and the second cutting edge can be positioned adjacent an outer circumference of the cutting tool.

Abstract: The present invention provides a new drilling tool useful in machining hydraulic port seals for fluid power ports. The drilling tool drills the port hole to size in a solid material for the minor thread diameter in combination with forming the port in a single operation. The drilling tool has a tool holder having a rotational axis, a first drilling insert having cutting surfaces on a first side and a mounting surface on a second side, at least one second drilling insert having a predetermined cutting surface portion and a mounting portion which is mounted on the holder at a location from the rotational axis of the holder. The at least one second drilling insert has first and second portions which engage and machine a work piece in a drilling operation to form a spot face and a seal form.

Abstract: An insert for a deburring tool is used to machine openings of bores that are formed in metal work pieces. In an exemplary embodiment, the insert has an inward portion, a central portion connected to the inward portion, and an outward portion connected to the central portion. The central portion has a dovetail-shaped retaining feature that attaches the insert to the deburring tool.

Abstract: A tool shank and a replaceable cutting insert are provided for a rotary cutting tool assembly. The tool shank has a drive surface including a central portion, a first portion of generally planar shape extending away from the central portion and a second portion of generally planar shape extending away from the central portion in a direction generally transverse to a central axis of the tool shank. The replaceable cutting insert has a driven surface including another central portion, a first portion of generally planar shape extending away from the other central portion and a second portion of generally planar shape extending away from the other central portion in a direction generally transverse to a central axis of the insert. The central portion of the driven surface has a curved surface transitioning between the first portion and the second portion of the driven surface.

Abstract: An insert retention screw having a head with a radius that is sufficient size to fit within a mounting hole of a cutting insert and seat within a seating plane within the mounting hole that is generally perpendicular to the axis of the insert when the screw is at an angle of about 0-15 degrees is disclosed. The retention screw provided for holding a cutting insert in the pocket of a tool body. The pocket is partially defined by a floor and a seating surface. A threaded hole is at an angle that is taken with reference to the pocket floor. The insert has a mounting hole passing therethrough. The retention screw passed through the mounting hole and threads into the threaded hole so as to draw the insert against the seating surface.

Abstract: A twist drill or rotary cutting device, in particular a drill, comprising a tool head or cutting insert consisting of a hard cutting material and a tool shaft which clamps the tool head between two clamp extensions that project axially from said tool shaft in such a way that the tool head is interchangeable. In the fixed position, the interconnected clamping surfaces of the tool head and the clamping extensions of the tool shaft lie on the surface of a truncated cone shaped fixing peg running coaxially with the longitudinal axis of the tool shaft. The fixing peg tapers in the insertion direction, facing the chuck end of the tool shaft.

Abstract: The invention relates to a dual-cutting drilling tool. The drilling tool comprises a base body (14) which is rotatable about a drill axis (36) and in which two plate seats (16) are arranged on the front face thereof for receiving identically configured alternating cutting plates (16). The alternative cutting plates are respectively provided on a main cutting edge (28) thereof with an adjacent first face (30), forming a cutting wedge, and a free surface (24). The main cutting edges (28) of the alternating cutting plates (20) complement each other in the region of a central, offset cutting part (28?), forming a cross-cutting edge which is interrupted by a center hole (60). The aim of the Invention is to reduce the risk of breakage in the center area of the alternating cutting plates and to provide better guidance for the tool.

Abstract: A spade drill insert and drilling tool assembly is provided wherein the lands of the spade drill insert have helical margins which provide increased stability during cutting operations and the holder has a clearance surface providing better chip evacuation. The margin may have a helical trailing side or leading side, a parallel helical margin, or may also include a gullet or flute adjacent the helical margin.

Abstract: A spot drilling tool includes a drill holder and an insert removably mounted to the holder. The insert is a standardized part configured to support a drill point in a predetermined position forward of the drill holder and centered on the rotational axis of the drill holder. The drill point has two flutes and two substantially conical land surfaces extending between the flutes. The land surfaces have centers of curvature offset from the rotational axis of the insert to provide radial clearance for the trailing portion of the land. A chisel edge at the tip of the drill point is supported by a tapered web defined between the diagonally opposed and offset flutes. Linear cutting edges are formed at the junction of a planar flute surface and the conical land surface. The cutting edges define a narrow included point angle of between 50° and 80°.

Abstract: A drill having a replaceable cutting head, modified to eliminate forces which would distort the pocket of the drill shank and otherwise concentrate stresses which would cause failure of the drill. The cutting head has a frustoconical depending connecting member received in a receptacle formed in the shank. In different embodiments, contact between the pocket formed in the shank and the cutting head connecting member is limited. In one embodiment, angle of drive surfaces is modified from prior art practice. In another embodiment, transition of at curved joints between vertical and horizontal surfaces is made more gradual. The drill preferably has flutes formed collectively by the shank and cutting head when assembled.

Abstract: A rotary cutting tool comprising a solid cutting head mounted to a shank. The cutting head comprises a cutting portion adjacent a cutting head front face and a mounting portion integrally formed therewith and extending rearwardly therefrom. The shank comprises a receiving portion extending rearwardly from a shank front face. When the cutting head is secured to the shank, the mounting portion is received in the receiving portion, and the shank front face is forwardly exposed and adjacent the cutting head front face.

Abstract: A drill includes a tip-forming front end having at least two straight cutting edges and at least two chip flutes extending from the tip end towards a rear end. Each cutting edge includes an inner portion disposed near a center line of the drill, and an outer portion disposed farther from the center line. The peripheral end of each cutting edge is in the form of a smoothly curved nose portion protruding radially with respect to the center line. The nose portion is formed by several circular segments having mutually different radii (R1, R2, R3). Adjacent ones of the radii are of different size.

Abstract: A gun-drill comprises a cutting-head detachably secured to a shank, having a common longitudinal axis and comprising mating peripheral surfaces. A shank coupling portion comprises a forwardly tapering shank fixation surface is formed at a front end of the shank, and a cutting-head coupling portion comprising a forwardly tapering cutting-head fixation surface is formed at a rear end of the cutting-head. Both the shank and the cutting-head coupling portion extend over a peripheral coupling angle ? of more than 180°. The shank and the cutting-head are assembled by positioning the cutting-head leading face in front of the shank trailing face, slidably inserting the cutting-head coupling portion into the shank coupling portion laterally to the axis of rotation A and rotating the cutting-head relative to the shank in a direction opposed to the direction of rotation R so that the cutting-head coupling portion and the shank coupling portion interlock co-axially.

Abstract: In an embodiment, the invention provides a tool for chip removing machining, including a replaceable cutting insert and a basic body. The basic body includes a rear fixing part, a front supporting part having an insert seat, and a tightening part spaced apart from the front supporting part by a first gap and from the rear fixing part by a second gap. The tightening part is connected to the basic body via a joint around which the tightening part is pivoted to press the cutting insert against the insert seat by a front finger. The rear fixing part includes a first channel having an inlet and an outlet for feed of a fluid toward the cutting insert. The tightening part includes an internal, second channel that extends between an inlet and an outlet.

Abstract: A drill in which a cutting head is releasably mounted on a tool shank. The cutting head is axially supported by the tool shank at four spaced apart axial support regions on shank support surfaces.

Abstract: The present invention relates to a V-notched web formed on a drill insert of a drill tool assembly. The V-notched web allows greater stability and feed rates, while decreasing the heat generated at the insert tip. The present invention is provided by a drill insert comprising a drill insert body having at least two cutting edges, a web between the two cutting edges, and a web thinning notch formed on either side of the web. Each web thinning notch forms a notch cutting edge having a positive rake angle.

Abstract: A rotary cutting tool that is composed of a tool shank with at least one chucking groove or chip flute and one exchangeable cutting insert. At the tip of the shank a recess for accommodating the cutting insert is provided. The tool shank, on its circumference, has a limb with a bearing surface that is inclined relative to the tool axis and that corresponds to a likewise inclined bearing surface on a wing of the cutting insert. The inclination of the bearing surfaces produces an axial force that retains the cutting insert on the tool shank. The abstract of the disclosure is submitted herewith as required by 37 C.F.R. §1.72(b). As stated in 37 C.F.R. §1.72(b): A brief abstract of the technical disclosure in the specification must commence on a separate sheet, preferably following the claims, under the heading “Abstract of the Disclosure.

Abstract: A solid drill bit for machine tools has a drill bit body and two indexable inserts arranged at a radial distance from one another in respective insert seats. The inserts have an essentially quadratic contour. Their front-end main cutting edges project axially beyond the drill bit body and radially overlap one another. The outer insert has an outer insert corner and a secondary cutting edge perpendicular to the main cutting edge that projects radially beyond the circumference of the drill bit body. To permit burr-free through-drilling, the main cutting edge of the outer insert is subdivided in its longitudinal extent into a radially inner working section and a rectilinear peeling section adjoining the working section and extending to the outer insert corner. The sections enclose a setting angle of 95° to 120°. The peeling section is set at a positive setting angle of 720° to 87°.

Abstract: The present invention relates to a drill and a drill tip for chip removing machining. The drill has a drill body, a drill tip and a shank portion. The drill tip comprises at least one cutting edge and at least one peripherally arranged guide member. The drill has a center axis. The guide member of the drill tip comprises a part-cylindrical first surface portion and an eccentric second surface portion. The first surface portion connects axially rearwardly along the guide member to the second surface portion.

Abstract: A cutting tool with a cutting insert and a pivotable screw and nut combination for holding the cutting insert. The cutting tool also has a feed mechanism to adjust the position of at least one cutting edge of the cutting insert in the cutting tool.

Abstract: A cutting tool including a cutter head and a holder. One of the cutter head and the holder has a recess formed in its axial end portion and defined by its circumferential wall. The other of the cutter head and the holder has a protrusion formed in its axial end portion, such that the cutter head and the holder are detachably attached to each other, with the protrusion being introduced in the recess by an axial distance. The above-described one has coaxial holes formed in the circumferential wall. The above-described other has an engaging surface which is recessed from an outer circumferential surface of the protrusion and which is held in engagement with a pin that is received in the coaxial holes. Each of the coaxial holes has an axis which is inclined, with respect to a plane perpendicular to an axis of the above-described one, in a direction causing the above-described axial distance to be increased by a cutting resistance generated in a cutting operation.

Abstract: The invention describes a drill plate with a clamping attachment in a rotatably driven base body, which on one of its end faces forms a centering groove that is open towards the top. A clamping slot extending into the material of the base body is arranged at the bottom of the centering groove. The centering groove is bounded by at least two opposing mounting jaws, with at least two diametrically opposing stop faces arranged in the region of the clamping jaws for providing centering contact with the drill plate. The clamping attachment is formed by a mounting screw which clamps the drill plate in the centering groove. To improve transfer of the operating torque from the drill plate to the base body and to facilitate handling, at least two centering fins that are diametrically opposed with respect to the transverse center axis are arranged on the drill plate. The centering fins contact corresponding stop faces disposed on the corresponding clamping jaws of the base body.

Abstract: A twist drill or rotary cutting device, in particular a drill, comprising a tool head or cutting insert consisting of a hard cutting material and a tool shaft which clamps the tool head between two clamp extensions that project axially from said tool shaft in such a way that the tool head is interchangeable. In the fixed position, the interconnected clamping surfaces of the tool head and the clamping extensions of the tool shaft lie on the surface of a truncated cone shaped fixing peg running coaxially with the longitudinal axis of the tool shaft. The fixing peg tapers in the insertion direction, facing the chuck end of the tool shaft.

Abstract: A deep hole drill comprising a cutter carrier, a replaceable cutting insert and at least one replaceable guide strip. The cutter carrier is embodied in such a way that it can be used for a predetermined nominal diameter range. In order to adjust the deep hole drill to the various desired nominal diameters in a quicker and more precise manner, a separate kit consisting of a cutting insert and at least one guide strip is associated with each nominal diameter. Fixed stops are provided on the cutter carrier for said kit.

Abstract: A multi-function miller cutter includes a shank with a receiving portion defined in the shank at an end of the shank. A threaded hole is defined in the receiving portion so as to secure a disposable cutter. An angle is defined between an axis of the shank and a center of the threaded hole.

Abstract: A cutting tool and a method for the production of cutting tools for metalworking characterized in that the holder body of the tool first is submitted to a surface hardening that results in the formation of compressive stresses in the surface and then submitted to a surface treatment that gives additional contribution of compressive stresses in the surface. In this way, it is allowed to, on one hand, be able to modify/machine or remove parts of or the entire phase-transition layer obtained in the surface hardening at the same time as additional compressive stresses are built up in the surface of a hardened steel material in the tool body.

Abstract: A deburring tool having an indexable cutting insert having four cutting edges. The cutting insert has a main body portion and a guide groove. The cutting insert is slidably retained in an insert pocket with the main body portion of the insert located in a generally rectangular slot of the insert pocket and with the guide groove located and engaging a guide member portion of the insert pocket. The cutting insert is moveable between a retracted position and an extended position by means of a spring which biases the cutting insert towards the extended position. The sliding movement of the cutting insert is performed by the sliding of the guide member within the guide groove.

Abstract: A spade drill insert and drilling tool assembly is provided wherein the spade drill insert body comprises curved cutting edges and a lip groove having a trough substantially parallel to a plane formed through each adjacent curved cutting edge, which provides a significant improvement in chip formation during cutting operations.

Abstract: A single tool that provides multiple machining operations for forming a lug hole through a vehicle wheel hub includes an end portion having a first diameter and a mid-portion having a second diameter that is greater than the first diameter. A spade drill bit is mounted upon the end portion and a bore cutting tool is mounted upon the mid-portion.

Abstract: The invention concerns a tool head for employment in machine tools with multiple indexable cutting inserts (20, 20?, 20?). The tool head includes a base body (12), a tool shank (14) projecting axially beyond the base body (12) and at least two blade receptacles (18, 18?, 18?) which are spaced apart at least in the circumferential direction for receiving respectively one indexable cutting insert. The active main cutting edge of the different indexable cutting inserts therein have a differing adjustment angle (?, ??, ??) relative to the axis of the base body. In order to reduce the blade costs, the same type of indexable cutting insert (20, 20?, 20?) is provided in the different blade receptacles.

Abstract: A solid drill bit for machine tools. has a bit body and two movable inserts located a radial distance apart in insert seats of the bit body. The inserts have a rectangular or quadratic contour, project axially over the bit body with their major cutting edges and overlap in their working area. The outer movable insert projects radially beyond the periphery of the bit body with its outer cutting edge corner and with the adjoining minor cutting edge. Starting from the cutting edge corner, the minor cutting edge is inclined in the direction of the bit body at a setting angle of less than 3.2 °. The minor cutting edge has a guiding edge that is slidingly supported against the wall of the bore over at least part of its length due to a radially outwardly oriented thrust force.

Abstract: A double or multiple-edged drilling tool has a base body rotatable about a drilling axis, and at least two plate seats arranged on the front face for accommodating identical interchangeable cutting plates. The cutting plates each have a machining face, and a clearance face adjoining a principal cutting edge forming a cutting wedge, and a seat face facing away from the clearance face. A guiding land adjoins radially outwardly through each edge the machining face, the clearance face and optically the seat face. The cutting plates each have a hole for a retaining screw which is screwed into a threaded bore at the front face of the base body. The holes are aligned with their axis perpendicular to the clearance face of the associated cutting plates the threaded bores are aligned inclined to the drilling axis and inclined to each other in the base body.

Abstract: A drill improving the aligning accuracy of an insert and achieves a stable machining operation while maintaining the strength of the drill main body. The drill includes a drill main body rotatable about an axis, and a throwaway insert detachably attached to the drill main body. The drill main body includes a concave groove opening at a distal end face thereof, the concave groove includes guiding grooves extending in the direction of the axis on an inner surface thereof, the throwaway insert includes convex portions on an outer surface that are engageable with the guiding grooves, and the concave groove is formed so as to accommodate the throwaway insert. The throwaway insert is attached to the drill main body by insertion into the concave groove in a direction from the distal end face to the concave groove while engaging the convex portions with the guiding grooves.

Abstract: In a throw-away tipped drill, a slit is formed at the bottom surface of a tip attachment seat which faces towards the end of its axial line direction, with this slit extending towards the rear of the axial line direction. Furthermore, when seen from the end of the axial line direction, this slit is arranged as being displaced so as to be closer to a second end portion into which a shaft portion of a clamp bolt is threaded than to a first end portion which is pressed by a head portion of that clamp bolt. As a result, when, using the clamp bolt, the pair of outer side surfaces of the tip are pressed by the pair of internal side surfaces of the tip attachment seat, the pressing forces are mutually equal to one another.