Abstract: A parting/grooving insert formed of cemented carbide includes upper and lower surfaces of V-shaped cross-section adapted to mate with corresponding V-shaped walls of a holder. The walls form opposite sides of a slot in which the insert is frictionally held. One of the walls is formed on an elastically movable clamping arm of the holder which is elastically displaced away from the other wall when the insert is forced into the slot. Due to the elasticity of the clamping arm, the insert is frictionally secured. The upper and lower walls include recesses spaced apart by non-recessed portions of the respective surfaces of the insert which are engaged by the walls of the slot. Due to the presence of the recesses, the pressure acting on the non-recessed portions of the insert surfaces is increased.

Abstract: The present invention provides a cutting tool assembly having a cutting insert holder and a cutting insert. The cutting insert holder has a clamping jaw, a base jaw and an inner side surface extending therebetween. An insert pocket is defined between the two jaws and the inner side surface. The inner side surface is provided with a positioning member. A clamping screw passes through the upper clamping jaw and is threadingly connected to the lower clamping jaw. The cutting insert has a central body portion having a side surface provided with a location member which is engaged by the positioning member whereby the axial location of the cutting insert is fixed.

Abstract: A cutting tool assembly (10) having a body portion (12) and at least one cutting portion (14), the at least one cutting portion (14) having a clamping portion (16), an insert retaining member (18), a precisely located cutting insert (20) and a securing member (22) for ensuring that precise location of the cutting insert is maintained. If the insert-retaining member becomes damaged due to contact with a workpiece it can be removed from the cutting tool assembly and replaced.

Abstract: A tool for chip removing machining includes a holder and a cutting insert removably mounted therein. The insert includes a shaft having opposite ends and defining a first longitudinal center line. A cutting head projects integrally from at least one end of the shaft. The cutting head includes a cutting edge forming an angle of 45° with the first longitudinal center line. Alternatively, or additionally, the cutting head defines a second longitudinal center line forming an angle of 45° with the first longitudinal center line.

Abstract: A cut-off insert (1) used for cutting-off a piece from a work, comprising an end-cutting face (17); at least two flat rake faces (16) running approximately in parallel and forming at least two straight end-cutting edges (15) with the end-cutting face (17); a recessed end-cutting edge (25) formed between the straight end-cutting edges (15); a sloped breaker wall (18) extended and sloping from the flat rake faces (16) to a clamp-pressing face (29) of the cut-off insert (1); and a recessed rake face having a groove (26) extending from the recessed end-cutting edge (25) toward a clamp-pressing face (29) and formed between the flat rake faces (16).

Abstract: A cutting insert has a generally parallepipedal body formed with a pair of generally rectangular, planar, and parallel side faces, a mounting formation at at least one of the side faces, a pair of opposite edge faces between the side faces and each forming at each end of the body a cutting face bounded by a cutting edge, and a respective pair of at least partially circularly arcuately concave free faces at each end extending between the respective cutting edges. The cutting edges are arcuate and each cutting edge has a convex part and straight or concave part.

Abstract: A tool for parting or grooving includes a holder to which is mounted an adapter having an insert-receiving slot formed between support and clamping portions of the adapter. The holder includes a serration meshing with a serration of the adapter. Threaded holes are formed through the serration of the holder, and through-holes are formed in the adapter in alignment with respective holes of the holder. Screws extend through the aligned through-hole and threaded hole to secure the adapter to the holder. A slot intersects through one of the through-holes of the adapter to render the clamping portion elastically deformable. That through-hole includes a conically-shaped entrace surface, and the associated screw includes a conical head which acts as a wedge to force the clamping portion into clamping engagement with the insert.

Abstract: The invention describes a cutting tool, preferably a cutoff parting tool, having one or more replaceable cutting inserts. The cutting inserts comprises on the supporting and/or clamping surfaces embossed elements. Upon clamping the cutting inserts these elements cause a plastic deformation of the contact surfaces on the toolholder. In this fashion, the cutting inserts are additionally stabilized against lateral compressive forces and tensile forces forcing them out of the seat.

Abstract: A holder blade with a leading portion and a body portion. The leading portion includes a lower jaw and an upper jaw. The upper jaw has an upper side and a clamping surface. The lower jaw and the upper jaw have a gap between them forming a cutting insert pocket. The leading portion also includes an opening extending in a generally rearward direction from the cutting insert pocket, to allow resilient displacement of the upper jaw relative to the lower jaw. The leading portion also includes a protuberance extending from the upper jaw, so that on displacing the protuberance the upper jaw is resiliently displaced and the gap between the upper and lower laws is widened.

Abstract: A tool for chip removing machining includes a holder and a cutting insert clamped within a pocket of the holder. The pocket has upper and lower sides, and the cutting insert comprises an upper surface and a lower surface. The upper side of the pocket and the upper surface of the cutting insert comprise first cooperating contact surfaces defining a first flank angle. The lower side of the pocket and the lower surface of the cutting insert comprise second cooperating contact surfaces which define a second flank angle. The first flank angle is larger than the second flank angle. The lower surface of the cutting insert and the lower side of the pocket form intermeshing projections and recesses which define the second contact surfaces.

Abstract: A holding device for machine tool inserts includes a recess delimited by clamping jaws. The recess serves as a clamping seat for the insert. The holding device also includes a slot extending the recess and having a receptacle for a spreading body of a spreader key. The slot has a half-circular expansion on one of its edges serving as a receptacle for the spreading body. The cross section of the spreading body of the spreader key is a polygon outline in the shape of an isosceles triangle whose corners are each rounded with an equal radius of curvature.

Abstract: A cutting insert for grooving operations includes a shank portion and a forward cutting head. The shank portion includes an upper surface, a bottom surface and side surfaces, wherein a line of intersection between the upper side and a forward clearance face forms a main cutting edge. Between the main cutting edge and a secondary cutting edge there is provided a corner cutting edge. The corner cutting edge comprises a primary curved edge with a first radius extending from the main cutting edge, and a secondary curved edge with a second radius, larger than the first radius, that extends from the primary edge to a side edge and oriented perpendicular to the main cutting edge. The cutting insert also comprises an upper side confined by two longitudinal ridges and an elongated chip forming recess therebetween.

Abstract: A cutting insert clamping mechanism for use in a cutting tool. The cutting tool has a body portion and a clamping portion. The clamping portion includes a base jaw and a clamping jaw. The clamping jaw has on its lower side a forward clamping surface separated by a recess from a rearward clamping surface. A first narrow bridge section connects the clamping jaw to the body portion of the cutting tool. A second narrow bridge section extends generally towards the rearward clamping surface. As a result of the two narrow bridge sections, the forward and rearward clamping surfaces can resiliently bend independently, and thereby are capable of applying independent clamping forces to the insert.

Abstract: The shaping lathe tool, in particular for processing wheel rims made of a light alloy, consists of a rod-shaped holder (10) with a V-shaped longitudinal groove (28) for receiving a cutting insert (12) with a rounded cutter head (18), and a claw (16) which clamps the cutting insert (12) to the holder (10) and is fixed in place on the latter by means of a key and slot engagement (30) arranged parallel with the V-shaped groove (28) and a clamping screw. The front end (38) of the claw (16) is designed as a chip breaker. To provide a tool which resists extreme stresses, the cutting insert (12) is clampingly held in a V-shaped longitudinal groove (28) over a length of at least eight times the head radius, and is interlockingly fixed in place in the longitudinal direction by stop faces (22) extending normally in respect to the longitudinal direction of the groove.

Abstract: A toolholder assembly for holding a cutting insert has a removable blade for mounting the cutting insert and a toolholder body for mounting the removable blade. The removable blade fits within a pocket in the toolholder body having angled sides to positively capture the blade.

Abstract: A toolholder (1) for clamping a cutting insert (6), the toolholder including a rigid base jaw (2), an upper clamping jaw (3) defining with the base jaw a longitudinally extending insert receiving slot for releasably receiving the cutting insert in a predetermined position, the upper clamping jaw tapering towards a leading nose portion (12) so shaped and dimensioned to initially urge the cutting insert to the predetermined position prior to its clamping in the insert receiving slot.

Abstract: A holder for free-cutting machining tool inserts, especially for chiseling, piercing or cutting inserts, includes an essentially beam-like edge support (1) with a receiving pocket (5) constructed in its end for the blade edge inserts. Clamping jaws (9 and 11) define the narrow width of the receiving pocket (5). A slot (29) is configured in the blade edge support (1) forming a flexible pivot for moving one clamping jaw. An operating member (37) is provided for producing a clamping force in the area of the slot (29) on the movable clamping jaw (11). The operating member (37) is mounted in a bore (39) at some distance from the slot (29). The clamping force is transmitted to the movable clamping jaw (11) through a force transmission member (43) which is slidably guided in the blade edge support (1).

Abstract: A cutting insert for the turning of grooves in metallic work pieces includes a rear shank portion and a cutting head projecting forwardly from the rear shank portion. The cutting head includes two side cutting edges converging forwardly, and a main cutting edge interconnecting the front ends of the side cutting edges. Each side cutting edge includes a plurality of spaced apart grooves formed therein, whereby each side cutting edge is noncontinuous.

Abstract: A tool for chip-removing machining includes an insert holder and an insert that is mechanically connected with the holder via upper and lower interfaces. Each interface includes a pair of contact surfaces that extend at an obtuse angle relative to each other. Disposed centrally between one of those pairs of contact surfaces is a ridge, and disposed centrally between the other pair of contact surfaces there is a flute. Each of the recess and flute is defined by side surfaces that extend at an acute angle relative to each other. When the ridge engages the flute, a proper absorption of transverse forces acting upon the insert is guaranteed, whereby the insert is maintained essentially immovable in its position in order to guarantee a proper machining accuracy.

Abstract: A cutting insert adapted for cutting-off and grooving operations comprises a body adapted to be mounted in a holder, the body including a pair of side surfaces spaced apart to define a thickness of the body. The body further includes a bottom surface, a rear surface, a top surface and a front surface each extending transversely from one of the side surfaces to the other side surface. A wall is oriented substantially parallel to the side surfaces and is situated midway therebetween. The wall includes a pair of side faces spaced by equal distance from respective ones of the side surfaces, a front side extending upwardly from the front surface, and a top side extending forwardly from the top surface. The front and top sides intersect one another to define a cutting edge formed of the same material as the front and top sides.

Abstract: A toolholder for holding a cutting insert, particularly for grooving and/or parting operations. The toolholder comprises a base and a clamping arm forming between one another a pocket and a slot. The pocket is open at a front end thereof for receiving the cutting insert, and the slot extends rearwardly from a rear end of the pocket. A fastening screw extends through the slot from the clamping arm to the base for displacing the clamping arm toward the base in order to clamp the cutting insert within the pocket. A stop is provided for limiting an extent of movement of the clamping arm away from the base, for defining a maximum height of the pocket.

Abstract: A cutting insert for mounting on edge in the insert pocket of a toolholder. The cutting insert has a mounting surface parallel to the top surface of the insert and a second mounting surface angled relative to the top surface of the insert so that the insert may be mounted in a toolholder having either of these two surfaces. An insert mounted in a toolholder having an angled bottom surface is secured within the insert pocket with a greater lateral force.

Abstract: A cutting insert and toolholder for metalworking operations in which the insert is mechanically captured by a resilient clamping arm within a recess of the toolholder secured at three distinct locations. In one embodiment, a clamping arm resiliently secures the insert within the toolholder while in another embodiment a clamping arm is positively displaced to secure the insert within the toolholder.

Abstract: A cutting tool assembly (1) clamping mechanism (5) which secures a cutting insert (3) for performing cutoff, grooving, slotting, and profiling operations. The clamping mechanism (5) has resilient upper and lower clamping jaws (7, 9) for receiving and securing the insert (3). The cutting insert (3) has front and top faces (13, 15) that define a cutting edge (21) at an intersection thereof, a back face (25), and adjacent proximal and distal bottom faces (27, 29) contiguous with said front and back faces (13, 25) that define an angular lower seating portion (30). The lower clamping jaw (9) of the clamping mechanism (5) includes proximal and distal pocket surfaces (59, 67) forming an angularly recessed jaw portion that is complementary in shape to the angular seating portion (30) of the insert (3).

Abstract: A method and apparatus for cutting or parting-off the stock or workpiece in a lathe. The parting tool has a body, a cutting edge, and a rubbing pad permits substantially all the normal (radial) reaction forces to be reacted and neutralized within the body of the parting tool, substantially eliminating machine-tool chatter and vibration.

Abstract: An exchangeable cutting insert having a substantially prismatic shape is disclosed. The insert has an upper rake surface, an opposite, substantially parallel base surface and side surfaces, adjacent side surfaces intersecting at an insert corner. Each side surface also intersects with the rake surface so as to define a cutting edge. Each cutting edge comprises a major cutting edge portion extending from one insert corner and merging with a succeeding, associated minor cutting edge portion, which terminates in a successive insert corner. Chip diverting ribs respectively associated with each of the cutting edges are formed on the rake surface. Each rib extends from a region adjacent the merger of the major and minor cutting edge portions on its associated cutting edge, and is substantially coextensive with the region of merger and is spaced from this region by a portion of the rake surface.

Abstract: A blade-type holder for a cutting insert includes a blade body having front and rear slots. The front slot is closed at its rear end and open at its front end for receiving a cutting insert. The rear slot has a closed front end spaced rearwardly of the closed rear end of the front slot so that a portion of the blade body disposed between those closed ends defines a spring hinge. The spring hinge interconnects a base and camping portion of the blade body. The base portion is disposed below the slots, and the clamping portion is disposed above the slot. An operator employs a tool to manually apply a downward force to the clamping portion at location rearwardly of the spring hinge to cause the front end of the clamping portion to swing upwardly about the spring hinge, to widen the front slot. After a cutting insert has been replaced, the manual force is released, whereupon the front end is swung downwardly into clamping engagement with the cutting insert by the restoring force of the spring hinge.

Abstract: The present invention relates to a tool arrangement (5) which includes a parting tool (6) or the like which is intended to cut off or remove a machined section from the raw material (3) held firmly in a holding device (2). Located adjacent the parting tool (5, 6) on the side thereof that is proximal to the raw material (3) is a bifurcate device (7) which is intended to coact with the edge region (3b, 6b) of the raw material that lies proximal to the machined section, at least when parting of the machine section (3a) is completed, so that upon axial movement of the parting tool and/or bifurcate device a given length of raw material will be withdrawn from the holding device (2). The invention also relates to a method of moving the raw material out of the holding device.

Abstract: The invention relates to a cutting insert (100; 200) for material-removing machining, especially turning, grinding, engraving and boring a workpiece (36), the at least one-sided overlap of which forms the first face (28) with at least one cutting edge (26) and the surrounding side surfaces of which form at least one free face (29). To improve cutting effectiveness, the flank (29) has one or more recesses (32) at a distance (h.sub.1) from the cutting edge (26; 34).

Abstract: A metal cutting tool comprising a cutting insert and a cutting insert holder is described. The insert has a body portion and a head portion. The head portion has an upper rake surface, a front relief flank surface, and a cutting edge defined between the first two. The holder is formed with a pair of jaws which clamp the insert. The first jaw abuts an upper surface of the insert adjacent the rake surface while the second jaw abuts a lower surface of the insert, adjacent to a base edge of the relief flank surface. A portion of this second jaw extends beyond the base edge, forming a projection. The holder is provided with a coolant flow channel having an input adapted to be coupled to a coolant source. A downstream portion of the channel terminates in a coolant flow outlet formed in the projection. The downstream portion and the outlet are arranged such that a coolant outflow from the outlet is directed substantially parallel to the relief surface.

Abstract: A thread cutting insert comprises a center portion and a plurality of cutting corners project outwardly from the center portion. Each cutting corner comprises a pair of outwardly converging cutting edges which are joined together by a curved tip. Each cutting corner includes a chipbreaking protrusion extending upwardly higher than the upper face of the center portion of the insert. The protrusion includes a front portion facing the tip, and a pair of upwardly converging sides. The front portion and sides are spacially confined to the cutting corner.

Abstract: A metal removing tool, in particular lancing insert, has a holder (10) with a slot-shaped recess (11) and a cutting insert (12) detachably held therein under a prestress by means of an elastically expandable clamping arm (101) designed as one side of the recess (11). The opposite cooperating insertion and bearing surfaces of the cutting insert (12) and slot-shaped recess (11) have a V-shaped cross-section. At its insertion and bearing surface facing the clamping arm (101), the cutting insert has a plurality of substantially flat partial surfaces (124, 125, 126) arranged behind each other in the insertion direction. Two surfaces enclose an obtuse angle .alpha. and form a salient point at the ridge (127), so that the clamping arm (101) engages the cutting insert (12) between the ridge (127) and the cutting edge (121) in the clamping state.

Abstract: A cutting insert is formed with a plurality of cutting edges, a cutting surface spaced inward from the cutting edges, and a continuous land having an outer periphery at the cutting edges and a curved inner periphery spaced inward therefrom and outwardly delimiting the cutting surface. The land dips at the inner periphery generally centrally of each edge toward the surface and thereby forms generally centrally of each edge at the inner periphery a region of minimal height above the surface.

Abstract: A cutting insert for grooving operations with chip control features having an insert body with peripheral walls, sides and first and second end walls to define cutting edges within cutting edge regions and adapted for mounting in a pocket of a toolholder assembly. A land extends rearwardly from the end wall and defines a width. A descending wall initiates in the land and terminates in a floor having a forward, a rearward and opposed side edges. A back ramp extends upwardly from the floor rearward edge and terminates at the respective peripheral wall to define a cavity. A pair of projections extend longitudinally along the sides of the cavity to promote chip control and intersect with diagonal side ramps rearward of the cavity. The side ramps may be used to provide a chamfer on the edges of the machined groove.

Abstract: A cutting tool for metal machining, in particular for grooving and parting operations, comprises a cutting insert-holding blade part (2) and a tool shaft (1), whereby both are formed with mutually matching joint portions. The blade part has a wedge groove (13) and the tool shaft a wedge part (18). This wedge part (18) comprises a movable wedge (20) with which the width of the wedge part can be varied in order to obtain a play-free joint with the wedge groove of the blade part.

Abstract: A cutting insert for metal cutting includes a body portion of a generally polygonal shape having a cutting end including a front end wall, sides, and top and bottom surfaces. The intersection of the top surface, end wall and sides forming a cutting edge. The top surface includes a cutting land sloping downwardly and inwardly from the cutting edge, a chipgroove area adjoining the cutting land and extending inwardly therefrom and disposed at a lower elevation than the cutting edge, and an upsloping chipbreaker portion adjoining the chipgroove area and the cutting land and leading to a plateau disposed at a higher elevation than the cutting edge and chipgroove area. The chipbreaker portion is configured symmetrically about a line bisecting the top surface between the sides and includes a forwardly extending fingerlike projection on either side of and continuous with a rearwardly recessed region bisected by the line.

Abstract: The invention relates to a cutting insert (10) for material-removing machining, especially for milling, turning or punching, with at least one cutting edge (12) and at least one chamfer (15) into which project depressions, or recesses (17) adjacent at a distance from the cutting edge and narrow them locally. To permit a very soft cut, stabilise the cutting edge (12) and attain high feeds, them are additional depressions (13) or recesses parallel to the depressions extending to the cutting edge and/or interrupting it for further narrowing the chamfer sections.

Abstract: A diamond-coated tool and a process for making them. The process includes a sintering step. In that step, a substrate is sintered in an atmosphere and for a time and at a temperature so that superficial, exaggerated grain growth is promoted that imparts a surface roughness which may serve as anchoring sites during a subsequent diamond coating step which is performed by a vapor deposition technique. The diamond-coated tool or wear part includes a large grain substrate surface, and a high bond strength between the diamond coating and the substrate surface.

Abstract: Relatively thick-walled (or solid) tubular members may be cut by cutting tools which include a frame assembly which is concentrically positionable (either interiorly or exteriorly) relative to the tubular member to be cut. A radial cutting assembly defines a cutting plane and is connected to the frame so as to be rotationally movable about the longitudinal axis of the tubular member to be cut. The radial cutting assembly carries a bit subassembly (preferably a pair of generally radially opposed cutting assemblies) for cutting the tubular member. A drive/indexing assembly is provided so as to rotate the rotatable ring (and thereby cause the radial cutting assembly to move orbitally about said tubular member), and index the bit radially toward the tubular member in response to rotational movement of the radial cutting assembly.

Abstract: In order to improve cutting insert economy with simplified manufacture, an exchangeable insert (1) is configured generally symmetrical in the form of a four-cornered plate with four cutting edges (4) in the corners respectively and with plane-parallel abutment surfaces (5) disposed between the cutting edge portions and at right angles to each other. All of the cutting edge portions are mutually identical to each other, and each cutting edge portion is symmetrically formed about a bisector which passes through a circular center hole in the insert. This is provided in order to achieve a high degree of accuracy with respect to position and direction when attaching the cutting insert to the holder (3).

Abstract: A metal cutting tool having a metal cutting tip with at least one cutting edge defined between a rake face and a relief flank and at least one recess formed in said relief flank and constituting a coolant channel and extending towards said cutting edge and being spaced therefrom by a spacing s which is of the order of the prescribed permissible width of flank wear VB.sub.max.

Abstract: A cutting insert for chip forming machining of workpieces is disclosed. The insert includes at least one end-positioned cutting head having an upper surface with a cutting edge extending across the width of the cutting insert and the ends of the cutting edge adjoining front chip surface side portions. A chip-deforming depression is provided between the front chip surface side portions. The rake angle of the chip surface side portions is consistently negative while the rake angle of a surface of the depression adjacent the cutting edge is consistently positive.

Abstract: A cut-of tool comprises a thin holder plate of steel, and a cutting insert of cemented carbide. The holder plate has an outwardly opening, insert-receiving recess defined by a bottom wall, an inner wall and an upper wail which is part of an elastically movable clamping arm serving to retain the insert in the recess. The insert has both upper and lower grooves of V-shaped cross-section, which are adapted to cooperate with corresponding V-shaped ridges associated with the recess. Between the insert and the bottom wall of the recess, there is provided a dismountable spacer element of cemented carbide, which has on its upper side a V-ridge for engaging a corresponding V-groove in the underside of the insert. The spacer element is maintained in place, on the one hand, by a countersunk connecting device in the area of the outer end of the bottom wail and, on the other hand, by a male-female connection between the inner wall of the recess and a rear end of the element.

Abstract: A portable cutting tool has an annular frame for surrounding the pipe. A rotatable ring on the frame carries a radially fed cutter which includes a bit subassembly for cutting the tubular member. The bit subassembly is indexed in response to orbital movement of the cutter. The bit subassembly includes a bit planar support block which has a dimension (as measured parallel to the longitudinal axis of the tubular member being cut) which is less than that of the bit which it carries. In such a manner, a channel passageway may be formed between the bit support block and the tubular member being cut as the bit penetrates into the tubular member during the cutting operation such that lubricating/flushing fluid may be directed to the bit.

Abstract: The invention relates to a cutting insert for machine tools wherein the insert adjacent its cutting edge has a chip forming device. The insert has a cutting edge and a planar surface adjoining the cutting edge. A recess is located downstream of the cutting edge and adjoining the planar surface. Various surfaces defining the recess are designed to engage a formed chip and bend it laterally. Obliquely upwardly directed abutment surfaces adjoining the planar surface are adapted to engage the edge flanks of the chip and bend the chip upwardly for breaking the chip into pieces.

Abstract: The present invention relates to a turning insert that comprises a generally rectangularly shaped body having a front end surface with a main cutting edge at the intersection between the front end surface and an upper land area. A chipforming area is provided in the forward portion of the upper surface and is shaped in the form of a number of distinctly provided recesses and ridges in order to promote improved chip control and to obtain narrower chips in grooving operations.

Abstract: A cut-off tool includes a plate-like holder and a cutting insert retained by a clamping arm. The insert has on its underside a V-shaped groove cooperating with a ridge of analogous V-shape on the holder plate. The V-groove has two flank surfaces extending at an obtuse angle to each other. The male edge or V-ridge similarly has two flank sides, each of which is broken by a break line so as to form two part surfaces, the inner part surfaces, located closest to the central portion of the V-ridge, enclosing an obtuse angle which is, on the one hand, greater than the corresponding obtuse angle between the outer two part surfaces and, on the other hand, smaller than the obtuse angle between the flank surfaces of the V-groove.

Abstract: A metal cutting tool having a metal cutting tip such as a replaceable insert, having top and bottom faces and a plurality of peripheral faces and a rake face forming part of the top face. A cutting edge is formed at the intersection of the top face and one of the peripheral faces. Chip forming means is formed on the top face and comprises, in lateral sectional view, successive portions of which at least one is relatively recessed with respect to a preceding or succeeding portion. A through-going bore is formed in the insert and extends from one of the bottom and peripheral faces to the relatively recessed portion in a direction towards the cutting edge.

Abstract: The invention relates to a metal cutting tip having an upper face and a curved relief face, defining between them a substantially circular cutting edge. A chip former is located in the upper face and comprises a plurality of substantially radially directed recesses formed in the upper face. The recesses extend from the land at the cutting edge to a substantially centrally located deflector wall. The recesses are positioned to deflect cut metal into a curved rigidized shape and against the deflector wall to cause breaking thereof.

Abstract: Surface coating includes alternating first and second ternary layers, wherein the first layer TiAlN.sub.x has a higher nitrogen content and is considerably thinner than the second layer TiAlNy. The first layer is preferably applied by decreasing the nitrogen content of a reactive atmosphere from a maximum to a minimum during sputtering of a TiAl target. The second layer is then applied by sputtering the TiAl target over a longer period of time while the nitrogen content is maintained constant at the minimum. When a further first layer is applied, the nitrogen is again increased to the maximum.