Abstract: A disposable cutter includes a multi-side body including a top surface, a bottom, and a plurality of sides. A stepped hole is defined through the body and a bolt extends through the stepped hole to fix the disposable cutter to a shank. Each of the sides is inclined an angle relative to a vertical line. A recessed area is defined in the top surface and at least one inclined surface is connected between the top surface and the recessed area. A safety edge is defined between the top surface and the side connected with the top surface. At least one inclined surface is directly connected with a cutting edge. The cutting edge and the safety edge are located on two sides of a line passing through a center of the stepped hole. The safety edge contacts an inner periphery of the hole so as to provide a support to the disposable cutter.

Abstract: A seal for an attachment to a surgical motor is provided by cutting threads into the inner surface of the nose cone of the attachment whereby the helical wound threads are in a direction opposite to the direction of the rotating shaft of the instrument being supported by the attachment. The motor can likewise by configured to define a seal where an attachment is not being utilized.

Abstract: An adaptor shank for SDS format pneumatic hammer/drill guns, the adaptor shank having a drill bit receiving end with drill bit locking means and an SDS format end for locking engagement with SDS format pneumatic hammer/drill gun, thereby allowing the drill bit alone to be discarded and replaced upon wear or breakage.

Abstract: A valve seat and valve guide machining tool for the precision machining of valve seats and valve guides in a cylinder head of an internal combustion engine is disclosed, comprising at least two tool parts (3,5) of which a first comprises at least one geometrically defined cutter (11), provided for the valve seat machining and a second comprises at least one geometrically-defined cutter (15), provided for valve guide machining, which are connected to each other by means of a precision interface (17). The precision interface (17) is a squat conical connection, comprising a first plane surface (19) on the first tool part (3) and second plane surface (21) on the second tool part (5), arranged perpendicular to a mid-axis (23) of the tool (1) and, in the assembled state of the tool (1), lie adjacent to each other, said first tool part (3) being made from steel.

Abstract: A lock body in a locked state is inserted radially inward of an outer surface. A stopper body in a contact state holds the lock body in an unlocked state. The stopper body in a non-contact state is retracted from the lock body. A pressing body is switchable between a standby state and a retracted state. The pressing body in the standby state selectively contacts a central shaft when an insertion portion is inserted in a support cylinder. The pressing body in the retracted state is retracted from the stopper body. An urging member urges the pressing body into the standby state, and urges the stopper body into the contact state. The urging member detachably engages the pressing body to the stopper body. Thus, the structure of the cutter holder is simple.

Abstract: A holesaw mandrel assembly has a mandrel body with a first end to be coupled with a drill motor and a second end extending from the body. The second end receives a holesaw. The first member is positioned on the second end. The first member is axially movable on the second end. A friction surface is on the first member. The friction surface is adapted to contact a base surface of the holesaw such that upon contact with the friction surface, the holesaw is fixed in position. The friction surface moves between a first contact position and a second release position. A mechanism on the first member moves the friction surface between the first and second position.

Abstract: An insertion end of a tool is driven along an axis at least partially rotary or percussively, which extends along the axis within a maximum guide diameter. At least one longitudinally closed locking groove and rotary driving groove is longitudinally closed at a longitudinal locking end towards the free leading end. The rotary driving groove has a groove width with at least one tangential force contact surface. At least two rotary driving grooves have a length of at least three times that of the guide diameter are arranged on the tool-side ahead of the longitudinal locking end, and have a contact length at least 1.5 times the guide diameter configured to be one fifth of the guide diameter.

Abstract: A twist drill for drilling with a countersink cutting arrangement, and a cutting tool with a countersink cutting arrangement, and a cutting-chamfering tool. 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.” The purpose of the abstract is to enable the Patent and Trademark Office and the public generally to determine quickly from a cursory inspection the nature and gist of the technical disclosure. The abstract shall not be used for interpreting the scope of the claims. Therefore, any statements made relating to the abstract are not intended to limit the claims in any manner and should not be interpreted as limiting the claims in any manner.

Abstract: The invention relates to an exchangeable rotary tool for a hand-held machine tool with a drill and/or hammer function, especially for a hammer drill. Said rotary tool comprises an insertable shank to be accommodated in a tool holder of the hand-held machine tool, said shank having at least two driving fins extending along its longitudinal extent for rotational engagement. The driving fins (7), when seen in the cross-section, are diametrically opposite on the insertable shank (2) and at least one of the driving fins (7) has an axial interruption (10) for the purpose of axial locking. The invention also relates to a corresponding method of production.

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 drill bit extension device is disclosed for use with a quick release drill chuck, the device including a body portion for securing a replacement drill bit and a stem structured and arranged for insertion into the quick release drill chuck.

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: A shank of a rotary-percussion working tool (2) has at least two, diametrically opposite locking grooves (5a, 5b) each having a locking shoulder (11) at an axial locking end (3) and spaced from a free end surface (4) of the shank (1), and an end shoulder (12) axially spaced from the locking shoulder (11) in a direction of a working tool-side end of the shank (1) and spaced from the axial locking end (3) of the shank (1) by a length (L) amounting at least to three times of a guide diameter (D) of the shank (1), and at least two entraining grooves (6a, 6b) mutually tangentially offset with respect to the locking grooves (5a, 5b), opening toward the free end surface (4), and having a tangential groove width (B) and at least one tangential, force application surface (7) extending over a contact length (K).

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: An improved drilling tool for drilling into and through walls for the purpose of inserting cabling within same, comprising a drill bit and an elongated primary shaft suitably adapted to create a chaseway within a wall during the drilling process. The elongated primary shaft may itself be the chaseway, in which case it is hollow, or it may carry a chaseway in the form of a conduit placed over a solid primary shaft. The cabling is then placed into the wall by use of the chaseway or by use of a separate conduit inserted into the wall through the chaseway.

Abstract: A device that allows the use of tool- and drill-bits in conjunction with a magnetic chuck comprises ferromagnetic material or a permanent magnet that is attached to the bit.

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: A shank for a rotary and percussive tool has a locking groove (3) arranged between two guided regions (1a, 1b) and axially closed at its opposite ends for receiving at least one radially displaceable and axially displaceable, within predetermined limits, locking member (4) of a chuck in which the shank is received, with the guide dimension (F) of the guide region being smaller than the width (B) of the axial region (A) of the locking groove (3) and that includes the radial extent of an entrain strip (2) provided in that region (A), and greater than the thickness (D) of the axial region measured in a direction transverse to the width measurement direction.

Abstract: A location and drive interface connection for machine tools and drive systems uses cooperating first and second sets of serrations at oblique angles on the mating surfaces of a drive component and a driven component for location and torque transfer. The oblique intersecting angles of the serrations provide for single precise location and alignment and high-efficiency torque transfer through the meshed serrations.

Abstract: A shaft tool with a machining section and a cylindrical shaft which comprises at least one internal coolant/lubricant duct which on its end facing away from the machining section comprises at least one orifice, wherein the shaft forms a conical fitting surface that encloses the orifice. A device comprising a shaft tool and a connection piece, the connection piece comprising a centric coolant/lubricant supply duct which exits in an apex region of an inner cone which accommodates in a positive-locking manner the conical fitting surface of the shaft tool, the conical fitting surface facing the inner cone.

Abstract: A surgical instrument holder has a shank having a coupling end, a handle attached to an opposite end of the shank, a coupling device, and a locking mechanism. The coupling end has an interface thereon for receiving an instrument. The locking mechanism has an annular locking component, a spring, a ring which slides on the shank, and a locking device. The annular locking component is mounted so as to slide along the shank. The locking device cooperates with the locking component so as to lock the instrument onto the interface. The spring biases the locking component in a locking direction and bears on the ring. The ring is disengageably lockable to the shank via a connection device so as to enable quick disassembly for cleaning and component sterilization.

Abstract: A preferably rotationally driven tool is specified for the deburring of openings, such as for example bores that open laterally into an essentially cylindrical recess. The tool has a cutting head that is seated on a shaft and that has at least one cutting edge that extends, at least in segments, in the axial direction. So that the deburring can be carried out reliably and with the lowest possible expense, a radial force-producing device is integrated into the tool, for example in the form of at least one internally situated flow medium channel, from which at least one branch channel goes out that opens in the area of the cutting head or in the vicinity thereof, preferably at a peripheral distance to the at least one cutting edge, in the external peripheral surface thereof.

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 shank for a working tool has at least three recesses (5) provided within the lockable region (3) and arranged in a cross-section (c-c) to the tool axis (A) at least at angles of 0°, 120°, and 240° within the radial reference dimension (R) of the shank, with at least one of the recesses (5) being axially closed toward a free end of the shank (1), and at least one protrusion (6) arranged circumferentially between two adjacent recesses (5) outside of the radial reference dimension, with the sum of central recess angles (?) of the recesses amounting to at least 150°, and a central protrusion angle (?) of the at least one protrusion (6) being smaller than a central recess angle (?).

Abstract: The invention relates to a rod-shaped tool made of sintered material that is used to machine a workpiece. Said tool comprises a rod center axis (1), a shaft area (6) and a chip space area (5) adjacent thereto in the direction of the rod center axis (1). The tool has at least one outside chip space (4), which encircles the rod center axis (1), in the chip space area (5) but not in the shaft area (6). The chip space (4) is situated at a minimum distance (a) from the rod center axis (1). A central recess (7) extends in the direction of the rod center axis (1) over the shaft area (6) whereby leading up and into the chip space area (5).

Abstract: A mechanized dental instrument includes an active part (2) and a sleeve (3) arranged on an end of the dental instrument which opposes the active part. The sleeve (3) is provided with a rotary drive means (4) that can, when assembled with the head of a handpiece, directly engage with a rotary drive means located upstream of the head of the handpiece. The drive means (4) is produced from a flat metallic piece which is fixed to the active part (2) by being slid over the axle (2a) of the active part (2), and which is provided with at least one opening (5) that is shaped to enable the circulation of plastic material forming the sleeve (3) when the sleeve (3) is molded over the axle (2a) to ensure the connection of the rotary drive means (4) on the axle (2a).

Abstract: In a cutting tool arrangement and a tool for chip removing machining, the cutting tool arrangement comprises a tool, fastening arrangement, and a shank. The tool is a one-piece unit. The axial channel is of non-circular cross-section to provide a key grip. An end of the axial channel comprises material at least partly blocking the axial channel.

Abstract: A drill has a unitary drill bit and chuck structure that includes a drill bit and a chuck. The chuck encloses a portion of the drill bit and has a thread. A rotatable drive element having a thread engages the thread of the chuck. The chuck is heat shrunk onto the drill bit to form a unitary structure through direct bonding of the chuck with the drill bit.

Abstract: A rotating tool such as a drill, a milling cutter, a countersink, a deburrer and the like, including a working part, which is driven in rotation about an axis of rotation for cutting machining, and also including an axially adjoining clamping shank for insertion into a clamping chuck of a drive machine. The clamping shank is provided with a number of clamping surfaces on its outer circumference for supporting a clamping jaw of the clamping chuck. The clamping shank has a shank radius in the region of each clamping surface which, as seen in a predetermined direction of rotation of the tool, rises from a minimum shank radius to a maximum shank radius as it passes over a range of angle of rise.

Abstract: A device for chip forming machining including first and second rotatable bodies arranged along a common axis of rotation. The first body forms a male element, and the second body forms a female element into which the male element is threaded for forming a threaded joint. The male element has an outer circumferential area displaced in the axial direction in relation to the thread thereof and which engages a corresponding inner circumferential area of the female element by a press-fit. One or both of those circumferential areas has an out-of-roundness, such that there occurs a press-fit along two or more preselected regions in the circumferential direction.

Abstract: A device for tapping a conduit, which conducts a flowing fluid, comprises a housing, which has a principal part, a fixing part running flush with the principal part for fixing to the conduit and an outlet part for discharging fluid from the tapped conduit. A rotating cutting device is provided in the principal part, said device being displaceable from a retracted first position into an extended second position, in which a section of the wall is cut out of the conduit. A telescopic shaft, which is fixed on one side to the principal part and on the other side to the cutting device, is provided. The telescopic shaft has at least two segments that can be displaced in relation to each other in a sealed manner and is fixed to the principal part in a sealed manner. The telescopic shaft does not protrude beyond the principal part as a result of its axial extensibility or retractability, thus ensuring a compact construction and ease of use.

Abstract: A cutting tool for rotary cutting includes a rotatable basic body and a replaceable cutting part or loose top, which is connectable to the basic body via a male/female coupling, which includes a groove and a male part. The groove is formed in a front end of the basic body and is delimited by a bottom surface and two side surfaces. The male part is insertable into the groove along the axis of rotation and protrudes rearwardly from the loose top. The male part has an end surface and two flank surfaces. In the front part of the basic body a forwardly open slot is formed, which separates two elastically deflectable legs wich clamp the male part in the groove. In either the end surface or the bottom surface a recess is formed for receiving a projection on the other surface. The recess is larger than the projection in order to enable the male part to reciprocate a short distance in the groove, whereby the loose top is self-centering with respect to the axis of rotation.

Abstract: A rotatable tool for chip removing machining includes a drill shank, and an exchangeable loose top mounted at an axially front end of the shank. Between these there is a coupling, which includes a male part on the loose top, and a groove in the basic body. By means of a slot, two deflectable legs are defined by the shank, which legs form a jaw for receiving and clamping the male part. The maximal width of the jaw upon deflection of the legs away from one another is larger than the maximal breadth of a wedge portion included in the male part. Furthermore, the angles of inclination of flank surfaces on the male part and side surfaces in the groove, are equally large in order to guarantee surface contact between said surfaces, when the legs are resiliently tightened against the male part. The wedge portion is of dovetail shape, wherein the loose top is drawn axially against the shank as it is being radially clamped by the legs.

Abstract: A cutting tool has a shank with a cylindrical portion that is adapted to fit closely within a tool holder. The shank is adapted to be engaged by a setscrew of the tool holder at a first contact point. A clearance surface is provided opposite the first contact point. The clearance surface terminates adjacent two circumferentially spaced points that make contact with the tool holder upon tightening the setscrew. These contact points are circumferentially spaced from the first contact point angular distances greater than 90 degrees and less than 270 degrees.

Abstract: An object of the present invention is to provide a drill bit which is simple in design, high in rigidity, and superior in durability and whose drilling function is in no way inferior to that of conventional drilling bits. To this end, in a drill bit comprising a cutting blade tip 2 which is united tightly to a tip end of a bit body 1 and a plurality of cutting blade portions 2a, 2b and 2c which are formed around the cutting blade tip 2, a flat surface portion 3 is formed in a side surface of the drill bit from between adjacent cutting blade portions to a base portion of the bit body 1 so that the bit body 1 is formed into a straight configuration having an approximately polygonal cross section.

Abstract: A tool employs a connect-disconnect coupling for a power drill to hold a multi-functional bit having at its one end a drill element adapted to form a hole and a countersink and at its other end a driver element to drive a screw or other type of fastener.

Abstract: An adapter device is disclosed for holding a blade having a first and a second side onto a distal end of a holder of a spade drill. The adapter device includes a body of generally cylindrical configuration, the body having a first and a second extremity. The body defines a first flute and a second flute which is disposed diametrically opposite to the first flute. The body also defines a bore which extends from the second extremity of the body for the flow therethrough of coolant. Additionally, the body defines a first and a second branch bore, the branch bores extending from the bore to the first extremity of the body. The second extremity of the adapter removably cooperates with the distal end of the holder and the first extremity of the body defines a diametrical slot disposed between the flutes.

Abstract: A twist drill, having a replaceable drill tip, comprising a drill bit shaft (1), a cutting insert (2) which is detachably fixed thereto and which forms the tip area of the twist drill, and comprises a flute (3) that continues into the cutting insert (2). The cutting insert rests, with a bearing surface (6) extending orthogonal to the center longitudinal axis (8) of the drill bit, on the face (7) of the drill bit shaft (1) and extends with a fixing stud (9), which centrally protrudes from the bearing surface (6), into a receiving recess (10) which is configured complementary thereto and which is provided in the face (7) of the drill bit shaft (1).

Abstract: The invention relates to a device for releasably connecting two coaxially aligned tool parts (1, 2) which can be axially pressed against each other on separating surfaces (36, 38) that face each other with a clamping device. According to the invention, at least one of the separating surfaces (38) is divided into several axially rigid and torsionally soft bearing segments (50) which are spaced in a peripheral direction, in order to dampen the torsional oscillations that occur during the work process and reduce noise.

Abstract: A depth stop for use with a drill bit comprises a tubular body having an opening therethrough. Used with a drill bit whose bit portion includes a cutting end, and a shank portion, the depth stop is frictionally positionable on the bit portion at a specified point from the cutting end, thereby indicating a specified depth. Depth stops are manufactured in different colors, each color corresponding to a specified range of drill bits that the depth stops will fit. The depth stops, manufactured from a sterilizable material, are intended for single use. The depth stop can be used with a drill bit and drill extender, where one or more depth stops provide multiple visual points of reference for the operator. The depth stops can be quickly mounted onto most any manufacturer's drill bits.

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 rock drill (1) for cutting rock comprising an elongated, helical shaft (2), which has, at one end, an insertion part (3) and, at the end opposite, a tool head (4) with cutters (5) made of hard material, wherein the helical shaft (2) is at least partially coated with a colored layer (7a, 7b) and the layer forms a lengthwise running wear indicator marking (8) inside the helical groove (8).

Abstract: In a cylindrical cutter head tool including a shaft part with a head support platform and a cutter head disposed on the cutter head support platform, the cutter head support platform and the shaft are an integral part made of tool steel and the cutter head is a sintered hard metal body, and the cutter head support platform and the cutter head include cooperating form-locking elements by which the cutter head is centered on the cutter head support platform and rotationally firmly engaged therewith.

Abstract: A milling cutter includes a body having three cutting edges formed by the body. An end of the body situated opposite the cutting edges defines a fastening end of the milling cutter. Each cutting edge extends from an outer periphery of the body substantially to a center rotational axis of the body along a substantially convexly curved path. Radially outer and radially inner ends of each cutting edge are situated axially rearwardly of an axially foremost point of the cutting edge. Each cutting edge lies on a respective imaginary sphere having a radius which has a center which that is spaced from the cutting edge in a direction toward the fastening end and spaced radially from the center axis.

Abstract: The present invention is to provide a machining tool bar in which mechanical machining properties are improved by using high stiffness composite material. According to the present invention, the tool bar includes an adaptor constructed to be coupled to a driving device, a body constructed to be mounted with cutting tools and a tip constructed to be supported by a workpiece, said body is constructed to be mounted with one or more cutting tools, wherein the adaptor and tip are made of metal material, the body is made of composite material having high stiffness, the composite material constructing the body is formed to surround at least a portion of the adaptor and at least a portion of the tip, and the metal material constructing the adaptor and tip and the composite material constructing the body are securely joined to each other in an interface therebetween.

Abstract: A drill for working in metallic materials includes a tool body having located in its front end at least one cutting insert, wherein the tool body is provided with one or several damping elements mounted such that during machining, a relative movement (i.e., sliding and/or deformation) of the tool body and the damping element is allowed to occur.

Abstract: A fluteless pyramid point drill for spotting holes for drills having an included angle from 90-160°. The preferred tool is double ended. Another embodiment features the pyramid point on the back end of a penetrating drill. An enhanced pyramid point geometry enables construction from technical ceramics. These embodiments included a notched pyramid, a dual pyramid, a beveled pyramid, and an eccentric pyramid. Another embodiment utilizes a grooved-body hollow pyramid for reaming holes. Geometries for a single sided penetrating drill for drilling hardened materials include a limited flute with a flute depth of ? the drill diameter. Point angle embodiments include a 0-20° primary cutting edge and a steeper relief angle with a negative rake along the edge, a radial edge and steep relief angle with a negative rake along this edge. Additionally a pyramid point may be superimposed on the dual point angle for superior centering guidance.

Abstract: A power drivable chuck 30 includes a body 72 which is formed with a shank-receiving opening 34 having a triangular cross section. A spring 104 is located about a forward section 78 of the body 72, and is captured within a chamber 102 between a base surface 98 of a sleeve 76 and a forward surface 100 of an intermediate section 80 of the body. A ball 90 is located in a passage 86 formed through the body 72 from an exterior surface 96 to the opening 34. A pair of slots 106 and 108 are also formed in the body in communication, and aligned, with the passage 86 on opposite sides of the passage. The ball 90 is formed with a through hole 112 and receives a pin 114 therein, with opposite ends of the pin extending from the ball and into respective ones of the slots 106 and 108. The spring 104 engages and normally urges the opposite ends of the pin 114 against the base surface 98 of the sleeve 76 normally to extend a portion 90a of the ball 90 into the opening 34 for locking a shank 42 within the opening.

Abstract: A rotatable tool for chip removing machining includes two parts, viz. a holder part, rotatable around a geometrical center axis, and a replaceable cutting part, which is rigidly connectable to a front end of the holder part via a male/female coupling. The coupling includes a tapering seat in the holder part and a tapering male member, protruding rearwardly from the cutting part. In the seat, there is a slot, which separates two elastically deflectable projections, that may be inwardly deflected towards each other during clamping of the male member in the seat. The male member is elongated in a radial direction, and the seat is in the form of a radial groove into and out of which the sheath body is transversely movable. The male member includes a dove-tail shaped portion received in a dove-tail shaper portion of the groove. A centering button on the male member enters a depression in the holder part to axially center the cutting part.

Abstract: A tool includes a tool body and a cutting portion detachably mounted thereon, the tool being rotatable about a longitudinal center axis. The tool body includes flutes formed in an outer surface thereof, and a pair of forward projections at a front end thereof. The cutting portion includes front flutes formed in an external side thereof, and a pair of recesses extending circumferentially in communication with respective ones of the front flutes. To connect the cutting portion to the tool body, the cutting portion and tool body are converged longitudinally so that the projections enter the front flutes. Then, relative rotation is produced between the cutting portion and tool body to align the front flutes with the rear flutes while causing the projections to enter the recesses and form therewith a bayonet coupling.