Abstract: A small-diameter drill having a diameter of ?3 mm or less and an end that has undergone cross thinning is provided such that in a front view, a flute portion cutting edge is curved in concave with a degree of concavity with respect to an imaginary straight line in a range of 0.5 to 2% of a drill diameter, the imaginary straight line connecting the radially outer end of the flute portion cutting edge and the radially outer end of thinning portion cutting edge, the ratio of length of the thinning portion cutting edge to length of the flute portion cutting edge is set to 0.6 to 0.9:1, and in an axially perpendicular cross-sectional view, curvature radius of a heel-side flute surface of the flute is set to be smaller than curvature radius of a flute surface along the flute portion cutting edge.

Abstract: A drill including: a chip discharge flute; and a cutting edge, the cutting edge being made up of a concavely-curved cutting edge portion formed on an inner circumferential side and a convexly-curved cutting edge portion formed on an outer circumferential side, the drill further including a cross section orthogonal to an axial center having a first convex curve corresponding to the convexly-curved cutting edge portion and a first concave curve corresponding to the concavely-curved cutting edge portion intersecting with each other, a flank following the cutting edge on the tip surface having an orthogonal clearance angle ? formed within an angular range of 9 to 20 degrees, and a ridgeline of the cutting edge having a chamfer formed with a width CW within a range of 0.002D to 0.02D (where D is a drill diameter).

Abstract: A drill includes: a chip discharge flute opened in a tip surface; and a cutting edge formed at an intersecting portion between an inner wall surface of the chip discharge flute on a side of a drill rotation direction and a tip flank formed on the tip surface, the cutting edge being made up of a concavely-curved cutting edge portion formed on an inner circumferential side and a convexly-curved cutting edge portion formed on an outer circumferential side, a cross section orthogonal to an axial center having a first convex curve corresponding to the convexly-curved cutting edge portion and a first concave curve corresponding to the concavely-curved cutting edge portion intersecting with each other.

Abstract: A drill comprises a drill body that is rotatable on an axis. Chip evacuating flutes, which are open on front flanks of the drill body and are extended rearwards, are formed in a periphery of the drill body on its front side. Cutting edges are formed along ridge lines where the front flanks intersect with wall surfaces of the chip evacuating flutes facing a drill rotating direction. At least first and second front flanks are formed on the front flanks in order of their locations in the drill rotating direction from its leading side to its trailing side. A clearance angle of the second front flank is greater than that of the first front flank. Intersection lines of the first and second front flanks cross the cutting edges.

Abstract: The invention relates to a deep-hole drill, comprising a first coating extending over the effective length of the guide section and a second coating that is applied to the tip of the drill in the cutting region, the region of which extends over an axial length that, at a maximum, corresponds to double the nominal diameter of the drill. In such a way, when the bore tip is worn by use, said tip can be recoated after sharpening without the nominal diameter of the drill tip substantially increasing, in particular even after being sharpened several times.

Abstract: The present invention relates to a rotary cutting tool consisting of a shank and at least one cutting section comprising a plurality of cutting teeth, the cutting section being conceptionaly and functionally divided into several sub-sections along the tool axis (“zones” for brevity), wherein each zone has its own core form and its own cutting edges, its own teeth land form and its own zone cutting length, these being selected according to the perceived task for which each zone of the tool is to be optimized.

Abstract: A drilling tool extends in a longitudinal direction and has a drill point and first and second major cutting edges, which extend approximately radially outward. The drill point is arranged eccentrically relative to a central axis, which is the same as the axis of rotation. The second major cutting edge is arranged by a cutting-height difference higher than the first major cutting edge. The first major cutting edge has a shorter radial edge length than the second major cutting edge. A method of utilizing the tool is also disclosed.

Abstract: A surgical dissection tool for cutting bone and other tissue includes a cutting head having an outer surface having non-paired or an odd number of flutes formed therein. Each flute includes a rake surface intersecting with the outer surface to form a cutting edge, and a relief surface opposite the rake surface. The relief surface and the rake surface form a first angle. Each flute also includes a leading angled surface extending from the relief surface to a distal end portion of the cutting head, the leading angled surface and the rake surface forming a second angle substantially the same as the first angle.

Abstract: A coolant-hole equipped drill includes a drill main body, a cutting edge portion which has a tip flank, a chip discharging groove provided with a front groove wall surface and a rear groove wall surface, a cutting edge formed at a ridge line portion where the front groove wall surface and the tip flank intersect with each other, a land portion formed between the chip discharging grooves adjacent to each other in the rotating direction, and a coolant hole drilled at the land portion and opened at the tip flank. The coolant hole includes a front hole wall surface, a rear hole wall surface, and an outer-circumference hole wall surface.

Abstract: A rotary cutting tool has a shank and an interchangeable cutting tip which can be coupled to the shank. The shank has a locking geometry having an undercut into which a locking projection of the cutting tip projects. Numerous lateral supporting surfaces and supporting counter-surfaces are provided for laterally fixing the cutting tip in the shank.

Abstract: There is now provided a twist drill and a method for producing a twist drill which method includes forming a flute of a twist drill. The drill has drill material and a tip portion with a cutting lip. The drill has a land structure and a flute to remove chip residue. The land structure has a flute wall and a cutting edge structure that is disposed longitudinally along the flute wall. The cutting edge structure has a first portion at the drill tip portion and a second portion disposed away from the drill tip portion. The flute wall extends further into the land structure at the second portion of the cutting edge structure than at the tip portion to provide a greater amount of drill material at the tip portion than at the second portion of the cutting edge structure.

Abstract: A drill includes a cutting edge. The cutting edge has a point angle which is continuously decreased from a center-position point angle A (herein, 0°<A<180°) at a center position to a maximum-diameter-position point angle of 0° at a maximum diameter position. The cutting edge has a relief angle which is continuously decreased from the center position to the maximum diameter position. The cutting edge of the drill has a relief angle at the maximum diameter position. Hence, the cutting edge also serves as a cutting edge for reaming. The ridgeline and relief face of the cutting edge have no corner, thereby providing good wear resistance.

Abstract: The present invention concerns fishing adapters for pilling a cable or the like through a hole drilled in a wall or other structure and in one aspect comprises a drill bit connector to enable the adapter to be demountably attached to a drill bit and an item connector to enable a cable or other elongate/linear item to be attached to the adapter, wherein the adapter further has a rotary coupling between the drill bit connector and the item connector to permit the drill bit to rotate as the adapter with cable or other elongate/linear item attached is pulled through a drilled hole without significantly twisting said cable or other elongate/linear item.

Abstract: A drill includes a cutting edge having a ridgeline. The ridgeline has a part of an ellipse and a straight line. It is assumed that the coordinates of a separation point of an ellipse portion from a straight line portion are (x0, y0). The straight line is a tangent to the ellipse at the separation point. It is assumed that a1 is an area from a tip end of the drill to x0, a2 is an area from x0 to the origin of the ellipse, and a3 is a negative area, along the x-axis. The ridgeline of the cutting edge is formed straight along the tangent in the area a1, and is formed along the ellipse in the area a2. A margin is formed in the area a3 continuously from a relief face of the cutting edge.

Abstract: The present invention relates to lead-through tool for pipes, comprising a tool body (1) having a rear end (15) provided with a means (16) for interaction with a rotary machine, preferably a handheld drilling machine, and a front end (17) at which there is provided either an adapter mechanism (18) for coupling to a removable implement (2) or an implement (19) integrated with said end (17), preferably in the form of a drill steel, wherein said tool body (1) is provided with holding means (13), at a position between said front (17) and rear (15) end, said holding means (13) being adapted to be able to hold a pipe (3) which is slipped onto said tool body (1) over said rear end (15) until interacting with said holding means (13).

Abstract: A drill bit (1) has a central axis (A) and a tapered cutting end part (2 ) terminating in a drill tip (3) at one end of the drill bit (1), a shank (4) extending from an opposing end of the drill bit (1), and a body (4a) extending between the cutting end part (2) and the shank (4). A plurality of flutes (5) are formed in the drill bit (1) and helically extend along the body (4a) into the cutting end part (2). Each flute (5) has a flute leading side wall (6) and a flute trailing side wall (7). A land (9) is defined on the body (4a) between each of the flutes (5) and extends to the cutting end part (2). In any body cross-sectional plane extending perpendicular to the central axis (A) through the body (4a), a land leading edge region (11) of each land (9) adjoining the flute trailing side wall (7) of a leading adjacent flute (5) is convexly curved.

Abstract: A drill for producing a drilled hole in work pieces has at least one main cutting edge on an end face. At least one secondary cutting edge is provided in the region of a circumferential surface of the drill. At least one circularly ground land circumferentially adjoins the at least one secondary cutting edge. The circularly ground lands extend over a first longitudinal section in the front area of the secondary cutting edge. In a following second longitudinal section, a secondary flank circumferentially adjoins the secondary cutting edge.

Abstract: The invention relates to a drilling tool (1) comprising a support shank (2) and an interchangeable cutting insert (3) which is fitted to the support shank (2) and which has an asymmetrical main lip (15) divided into a guide lip (10) having a supporting land (12) and a guide land (23) trailing the supporting land (12), and into a clearance lip (13) having a trailing clearance portion (14), wherein a guide land (28) and a supporting land (29) are formed on the lateral surface of the support shank (2) and continuously extend the guide land (23) and the supporting land (12), respectively, on the cutting insert (3) and additionally guide the drilling tool (1) on the inner wall of a drill hole during a drilling operation.

Abstract: The invention relates to a multi-blade solid carbide drill for cutting high-strength sandwich materials. The tool comprises a shaft section and an adjoining cutting part, into which a number of chip flutes that corresponds to the number of main blades is incorporated. In order to reinforce the curvature of the resulting chip, the chip flute of the drill comprises a chip flute rib in the region of the chip formation zone, said rib protruding from the chip flute surface and having a substantially wave-shaped cross-section (28), and said rib dividing the chip flute into two sections, a first chip flute section (30) forming the cutting rake and a second chip flute (32) forming the chip flute runout.

Abstract: The invention relates to a rotary cutting tool (10), in particular a milling tool, boring tool or a reamer, with a metallic base tool body (12) with at least one preferably helical flute (16, 18), preferably with a pair of flutes, wherein a cutting element (24, 26) of an ultra-hard cutting material such as polycrystalline diamond (PKD) or polycrystalline, cubic boron nitride (PCBN) for forming a helically running cutting edge (28) is associated with the at least one flute and is connected such as soldered to the base tool body (12; 42; 70; 94). In order to increase the service life and simplify the manufacture, it is provided that the cutting element (24, 26) is constructed as a one-part diamond body (24, 26) or from several diamond segments in the form of a section of a solid body that is/are received in a receptacle (20, 22) constructed along the flute (16, 18), wherein the helically curved cutting edge is constructed in the diamond body or the diamond segments in a material-removing manner.

Abstract: Chips are segmented to have a desired width and the chip controllability is improved and the tool rigidity is improved. A drilling tool is provided that includes: a tool body; a chip discharge groove formed at the outer periphery of the tool body; at least one sub-groove formed at an inner face facing the front side in the tool rotation direction T of the chip discharge groove; a rake face; a tip end flank face; and a cutting edge formed at a ridge line at which the tip end flank face intersects with the rake face. The plurality of rake faces form a step-like shape having at least one step section. The drilling tool is configured so that the turnup section of the sub-groove is turned up in a different direction from the direction along which the turnup section of the chip discharge groove is turned up.

Abstract: A cutting head having a cutting end and an opposite coupling end along a longitudinal cutting head axis; having a cutting head length; and including two major surfaces and a peripheral surface. A male coupling portion extends rearwards from the coupling end, between a base portion and a rear surface, with a circumferential peripheral surface, having a coupling length. A flexibility slot extends from the rear surface opening to the major surfaces, along the cutting head axis, having a slot length and a head slot length. The coupling length is equal to or less than half the head slot length, and the slot length is equal to or greater than half the cutting head length. The cutting head is self-clamped into a tool shank with female coupling portion, by a friction fit between the male and female portion peripheral surfaces, causing the cutting head to elastically deform.

Abstract: The modular carrier tool (2), in particular drilling tool, extends along a central longitudinal axis (4) in axial direction (6) and comprises a carrier (8) as well as a tool head (10) that can be reversibly mounted on the front-end of the carrier (8). The carrier (8) has a head retainer (14) for the insertion of the tool head (10) as well as clamping webs (24), which radially delimit the head retainer (14) and also have bearing surfaces (28). The tool head (10) comprises clamping surfaces (35) extending in axial direction as well as underhead bearing surfaces (34). In a mounted state the clamping webs (24) clamp the tool head (10) in radial direction to the clamping surfaces (35) and the underhead bearing surfaces (34) are pressed against the bearing surfaces (28).

Abstract: A three-flute drill includes: three chip discharge flutes; and three cutting edges each having concavely-curved and convexly-curved cutting edge portions, an axially perpendicular cross-sectional view orthogonal to an axial center having first convex and concave curves respectively corresponding to the convexly-curved and concavely-curved cutting edge portions intersecting each other, in the axially perpendicular cross-sectional view, a concave amount of the first concave curve being within a range of 0.01 D to 0.05 D in terms of a drill cutting diameter relative to a reference line connecting an outer circumferential point, at which a drill outer circumferential portion intersects with the first convex curve, and the axial center, and in the axially perpendicular cross-sectional view, a rake chamfer width being a distance from an intersection between a straight line through the intersection and orthogonal to the reference line and the reference line, to the outer circumferential point, and being within 0.

Abstract: A solid step drill, including a front tip and a rear end between which a center axis extends and around which the drill is rotatable in a predetermined direction. At least two cylindrical sections are concentric with the center axis, a first section extending rearward from the front tip and having a first diameter, and a second section extending behind the first section and having a second diameter that is greater than the first diameter, the first section transforming into the second section via a step. The tip includes two primary cutting edges, which individually co-operate with a respective chip flute that is delimited by a concave surface and countersunk in the first section and in the second section, the respective chip flute intersecting the step while forming a secondary cutting edge. Adjacent to the secondary cutting edge, a chip breaking recess is formed between a cutting edge line of the cutting edge and the concave surface.

Abstract: The application comprises a blank for producing a cutting tool with at least one inner bore for conducting fluids, wherein the blank comprises at least a first and a second portion along, its longitudinal axis, wherein the inner bore in the first portion is formed substantially in a straight line and parallel to the longitudinal axis of the blank, and the inner bore in the second portion has a first twist with a first twist angle greater than zero, wherein the blank can be obtained by a continuous pressing operation, in particular a continuous extruding operation. The application also describes an extrusion device for producing a blank, wherein the extrusion device comprises a control element for controlling the twist angle, in particular the first and/or second twist angle.

Abstract: A drill bit has a tool shank, a center axis, a first cutting region with at least one geometrically defined first cutting edge, the same having a cutting face arranged at a radial distance from the center axis of the drill bit. The first cutting edge forms a countersink angle with the center axis. The drill bit having a chip shaping stage functionally assigned to the first cutting edge formed by the cutting face of the first cutting edge and by a shoulder surface adjoining the cutting face and forming a shoulder angle with the same, wherein the shoulder angle is greater than 90°, and preferably greater than 100°. The cutting face runs at a radial rake angle with respect to an imaginary radial line which cuts the first cutting edge, the same functionally assigned to the cutting face. The radial rake angle is positive.

Abstract: A cutting head has a resilient male coupling member. The cutting head has a central resilience slit that extends between two major surfaces and opens out to the male coupling member and at least one lateral resilience slit that extends between the two major surfaces and opens out to a base surface. The central resilience slit and the at least one lateral resilience slit each have forwardmost points, located forward of the base surface. Also, a cutting tool that has a tool holder with the cutting head secured thereto. The tool holder has an insert pocket that includes a forward facing holder base abutment surface that has a female coupling member. In a locked position, the male coupling member is resiliently retained in the female coupling member. All points on the male coupling member are under deflection.

Abstract: This document provides novel drills and/or reamers that are well-suited for making holes in a variety of materials including, but not limited to, metals, ceramics, glass, wood, plasterboard, plastics, stone, composites, synthetics, silicon or multi-layered or hybridized substrates. In some embodiments, these drilling devices have some centers of mass that are offset from the axis of rotation. Accordingly, such drills and/or reamers may rotate and cut using a precessional pattern of motion. Precessional cutting devices may display a mechanical wave pattern in relationship to the longitudinal axis of the device. If the cutting device is fabricated from a flexible material, for example Nickel-Titanium, bodily deflection of the device may result during rotation.

Abstract: A rock drill bit having a shank fitted with a clamping end and a drilling tip located from the clamping end. The drilling tip has at least three blades and a central zone centered on a drill bit axis. The blades each include on a top side thereof a lip constituted by a leading chipping face and a trailing flank. The lips substantially converge onto each other within a the central zone of the drilling tip, wherein in the central zone, a long lip of the lips runs through the drill bit axis and has a commensurate overshoot segment extending beyond the drill bit axis.

Abstract: A milling and boring tool with a tool shaft which comprises a center axis, at least one geometrically defined rough cutter and at least one geometrically defined finishing cutter, and the at least one rough cutter and the at least one finishing cutter respectively comprise a chip groove. The milling and boring tool is characterized in that the chip groove of the at least one finish machining cutter has an opposite twist than the chip groove of the at least one rough cutter.

Abstract: A tool for machining workpieces, having a shank and a cutting insert having a base body held in the shank. The shank has a slot accommodating the cutting insert. The body has a central section with a central axis. At least one convexly bowed centering surface running in the direction of the central section. At least one drive element originates from the central section. The slot in the shank has at least one interior surface region shaped to cooperate with the at least one centering surface.

Abstract: A drilling tool for machine tools has a drill body, a cutting head arranged on the front face of the drill body and a shaft arranged at the end thereof, wherein the drill body has two chip flutes, which are delimited at their flanks by ribs and a first chip flute of which is spirally curved. A second chip flute is not spiraled or is spirally curved with a pitch differing from the first chip flute, preferably running in the same direction of rotation.

Abstract: A drilling/reaming tool includes a basic body which extends in a longitudinal direction. The basic body includes at least one end-side drilling major cutting edge, a main flute which is assigned to said drilling major cutting edge and is wound at a first helix angle, and a plurality of reaming cutting edges which are arranged circumferentially on the basic body and have in each case one reamer flute which is assigned to the respective reaming cutting edge and is wound at a second helix angle. The reaming cutting edges adjoin the at least one major cutting edge directly in the longitudinal direction. Each reamer flute is merged into the main flute.

Abstract: An elongated drill bit has a shank at one end and working end at the other. A flute portion is between the working end and the shank. The flute portion is continuous with the shank and working end and is generally unitarily formed with them. The flute portion has at least one flute with a helix angle between approximately 30° and 35°. The working end has a pilot tip with a cutting portion. A tapered web is formed in the flute portion, a thickness of the web at the tip of the working end is about 9% to 15% of the nominal diameter.

Abstract: A drill main body of an indexable drill is disposed first and second spiral flutes on a column-shaped outer circumferential surface with an inner blade tip cutting a hole center side mounted on a tip portion of the first spiral flute and an outer blade tip cutting a hole outer circumferential side mounted on a tip portion of the second spiral flute and the drill main body discharges chips through the first spiral flute and the second spiral flute toward a shank while hole machining is performed with the inner blade tip and the outer blade tip. The drill is a deep hole machining drill having a length of the first spiral flute and the second spiral flute equal to or greater than 4D relative to a drill diameter D that is an outer diameter of the outer blade tip.

Abstract: A drill of the present invention includes a first cutting edge and a second cutting edge each located at a front end of a cylindrical cutting part; a first flute and a second flute connected to the first cutting edge and the second cutting edge, respectively, in which the first and second flutes are positioned helically from a front end to a rear end on a peripheral section of the cutting part; and a first land and a second land each extended from the front end to the rear end on the peripheral section of the cutting part, in which the first and second lands are being located portions between the first flute and the second flute, respectively. The first flute and the second flute are separately extended from the front end to the rear end. The cutting part includes a first region in which a diameter of an inscribed circle in a cross section perpendicular to a rotation axis of the cutting part increases in a direction away from the front end and toward the rear end.

Abstract: A cutting tool for performing hole-cutting operations on a workpiece when the cutting tool is rotated about a central longitudinal axis includes a generally cylindrical body having a first end structured to be mounted to a machine tool and an opposite second end structured to engage and perform cutting operations on the workpiece. A number of coolant passages are defined in the generally cylindrical body, each coolant passage of the number of coolant passages is disposed at a first helix angle relative to the central longitudinal axis. A number of flutes are formed in the generally cylindrical body, each flute of the number of flutes includes a first portion at or about the first end of the generally cylindrical body, a second portion at or about the second end of the generally cylindrical body, and a transition portion disposed therebetween.

Abstract: A guide portion prevents the drilling hole from curving due to a skipping rope phenomenon, and also prevents the inner wall face of the drilling hole from being damaged, so that its surface roughness can be improved. Chip evacuating flutes 4 are formed in the periphery of a drill body 1 which has a stick shape and is rotatable on its axis O, from its front flank 3 toward the rear side. Cutting edges 2A are formed along ridge lines where the front flanks 3 intersect with wall faces 4A which are in the chip evacuating flutes 4 and face in a drill rotational direction T. A cutting edge section 2, where the cutting edges 2A are formed, is provided in the front side of the drill body 1. A cutting edge section 2 has an external diameter which is smaller toward the rear side in the axis O direction than the external diameter D at the cutting edges 2A. A guide portion 6 has a maximum external diameter part 6A at the front periphery side, and is provided to the rear side of the cutting edge section 2.

Abstract: A bevel head replaceable rotary tool is provided. The rotary tool includes a coupling protrusion and a coupling recess, plural sets of serrations provided on an outer circumferential surface of the coupling protrusion and an inner wall surface of the coupling recess, circumferential abutting portions provided on the tool body and the bevel head, and axial tight-contact portions, provided on the tool body and the bevel head. The serrations of the coupling protrusion and the serrations of the coupling recess arranged such that curvatures of circumferential circular arcs of the serrations of the coupling protrusion are greater than those of the serrations of the coupling recess or the serrations of the coupling protrusion and the serrations of the coupling recess have circumferential circular arcs with centers deviated from each other.

Abstract: A rotatable drilling tool has cutting edges (on a face side) that merge inwardly into a chisel edge, with the chisel edge(s) running on the face side about a central region surrounding the tool axis, with the chisel edges forming, in the innermost region (or about a point thinning region), a residual chisel edge, with cutting edge corners being formed at the outer ends of the main cutting edges, with a straight connecting line that runs through two cutting edge corners of main cutting edges situated opposite one another in relation to the tool axis, or if an opposite main cutting edge is not present, through a cutting edge corner and the tool axis, with the chisel edge inner region running from the outer end of the residual chisel edge within a region with an angle of between ?15° and +15° in relation to a parallel to the connecting line.

Abstract: A drill capable of suppressing inter-layer peeling (delamination) while keeping hole diameter accuracy even if the number of holed to be worked increases is provided. The drill includes a first flank which has a ridge line forming a cutting edge, a second flank which is adjacent to the first flank and has a ridge line forming a land portion, and a third flank which is adjacent to the first flank and has a ridge line forming a chisel edge. The drill further includes a fourth flank which is surrounded by a ridge line forming the first flank, a ridge line forming the third flank, and a trough line forming the second flank.

Abstract: A tool head includes an ovoid basic element disposed about a center axis, at least two chip grooves formed in the basic element, and a number of major cutting edges. Each major cutting edge is disposed in a convex course along a respective chip groove of the at least two chip grooves. The major cutting edges define with their radially outermost region a nominal diameter. A radial distance from each major cutting edge to the center axis in a front, tip-side, arc portion increases up to the nominal diameter and in a rear, shank-side, arc portion decreases back down to a minimum diameter.

Abstract: A drill bit, has a front side (5) and a circumferential surface (19) adjoining the front side (5). The front side (5) has a main cutting edge (7) including a transverse cutting edge (3) extending through a center axis (11) of the drill bit (1), and has two first and second main cutting-edge regions (13, 15) adjoining the transverse cutting edge (9) and extending radially toward the circumferential surface (19). The circumferential surface (19) comprises at least two chip flutes (21, 23), which between them delimit a first and a second web (25, 27), and three lands, of which a first land adjoins the end of the first main cutting-edge region (13) facing away from the transverse cutting edge (9), and serves as a free cutting-edge land (33), and additionally has a free cutting edge (39), a second land adjoins the end of the second main cutting-edge region (15) facing away from the transverse cutting edge (9), and serves as a guide land (35), and a third land serves as a support land (37).

Abstract: A drill of the loose top type, which is composed of a basic body and a replaceable loose top. In the front end of the basic body, a jaw is formed, which is delimited by two elastically bendable branches and an intermediate axial support surface, and in which the loose top can be securely pinched by inner support surfaces of the branches being resiliently pressed against side contact surfaces of the loose top. The two side contact surfaces of the loose top extend rearward from clearance surfaces that are included in the front end of the loose top. By forming the diametrical dimension between opposite side contact surfaces greater nearer the front end of the loose top, the branches of the jaw securely pinch the loose top in the area of the front ends thereof, where the branches have their maximal bending capacity.

Abstract: A method of joining a plurality of parts to form a unitary body includes providing at least two sintered parts. Each of the parts is formed of a hard metal composition of material. The sintered parts are assembled into the shape of a unitary body. Each of the sintered parts has a joining surface and when each joining surface is brought into contact the surfaces form a bonding interface therebetween. The assembled sintered parts are subjected to a temperature sufficient to fuse the sintered parts together at the bonding interface to form the unitary body. A wear resistant tool includes a plurality of sintered parts, each of the sintered parts is formed of a hard metal composition of material, wherein the plurality of sintered parts can be assembled into a unitary body, wherein the assembled parts are fused together at a respective bonding interface to form the unitary body.

Abstract: One non-limiting aspect of the present disclosure is directed to a multi-piece twist drill head. The multi-piece twist drill head includes a core piece formed from a first hard material, and a peripheral piece formed from a second hard material. The core piece and peripheral piece each comprise a cutting edge and are adapted to mate to provide a central region and a peripheral region, respectively, of the multi-piece twist drill head. A twist drill including the multi-piece twist drill head is also disclosed.

Abstract: A method of fabricating a micro drill, which includes a drill part for machining a hole and a shank part fixed to a motor, the drill part and the shank part being made of different materials. The method includes the steps of forming a drill part-forming powder compact having a recess in one end thereof, and forming a shank part-forming powder compact having a protrusion, the protrusion intended to be fitted into the recess of the drill part-forming powder compact, forming an assembly of the drill part-forming powder compact and the shank part-forming powder compact, with the protrusion fitted into the recess, and simultaneously sintering the assembly of the drill part-forming powder compact and the shank part-forming powder compact.

Abstract: In order to provide a rotary tool, in particular a drill, with a long service life together with high-quality drill holes, particularly in the case of through bores, the invention provides a cutting head which extends along a rotational axis and has a plurality of main cutting edges which extend radially outwards and each end at a cutting corner having a corner bevel, wherein the corner bevels are of differing designs, specifically in the form of a roughing bevel and in the form of a finishing bevel.

Abstract: A twist drill includes a cutting portion and a drill body. The cutting portion has a chisel edge, a segment relief surface, a chamfer relief surface and at least two flutes extending longitudinally to the drill body. Each flute has a rake surface and a gash extending away from the chisel edge. The cutting portion further has at least two cutting segments, each cutting segment having a first curved cutting edge, a second curved cutting edge and a chamfer cutting edge.