Provided is a method for manufacturing a sintered component, which can suppress occurrence of edge chipping when a through-hole is formed in a powder-compact green body and also has a good productivity. The method for manufacturing a sintered component includes a molding step of press-molding a raw material powder containing a metal powder and thus fabricating a powder-compact green body; a drilling step of forming a hole in the powder-compact green body using a drill; a sintering step of sintering the powder-compact green body after drilling, wherein the drill used for drilling has a circular-arc shaped cutting edge on a point portion thereof.

Disclosed are a drill and an insert for a drill having improved centering capability and cutting performance. In the drill of the present disclosure, central relief surfaces of cutting parts are processed as flat relief surfaces, and outer circumferential relief surfaces continuing from the center part to the outer circumferential surface of the drill are processed as curved relief surfaces, thereby enhancing the centering capability of the drill and minimizing the generation of drill vibration and burrs. In addition, in the drill of the present disclosure, the outer relief surfaces of the drill in contact with a hole to be drilled are processed such that an angle between the tangential lines of the outer relief surfaces is constant regardless of the size of the outer diameter of the drill, thereby achieving consistent performance of the drill despite change in the outer diameter of the drill.

Two discharge grooves (4) are formed in a drill (1). A cutting edge (5) is formed on a ridge section between an inner face (41) that faces a rotation direction (T) side of the discharge groove (4), and a flank (6). A thinning edge (7) is formed from an inner end (51) of the cutting edge (5) to the side of a chisel (9), by thinning processing, and further, a gash portion (8) is formed from an inner end (72) of the thinning edge (7), the gash portion extending in a circular arc shape and being connected to the discharge groove (4) further to an inner side in the radial direction than an outer peripheral surface (31). A circular arc groove (10) is formed in a section connecting a thinning face (71) and a gash face (81). The chips being cut by the thinning edge (7) are scooped up to the gash portion (8), are curled, and are discharged to the discharge groove (4). The chips are not likely to become caught by being provided with the circular arc groove (10). Since the gash portion (8) connects to the discharge groove (4) further to the inner peripheral side than the outer peripheral surface (31), the chips are cut relatively small.

Provided herein is a drill having less possibility of cracks in an inner periphery of a drilled workpiece and deformation of a workpiece upon penetrating with a drill, as well as delamination. A drill according to the present invention comprises two cutting blades which are formed symmetrical about an axis of rotation, wherein each of the cutting blades has a main cutting blade formed from a drill tip toward a peripheral side of the drill to become a shape with curves, a thinning cutting blade in a shape with curves formed in closer to the drill tip than the main cutting blade, and an U-shaped cutting blade in a shape with curves formed in closer to the periphery of the drill than the thinning cutting blade.

A rotary tool according to a non-limiting aspect includes a body having a rotation axis and extending from a first end to a second end. The body including: a first part including the first end; a second part located closer to a second end than the first part and having a larger outside diameter than the first part; a cutting edge located at a side of the first end; a ridge portion located in the first part and the second part, connected to the cutting edge and helically extending from the cutting edge toward the second end; and a flute located along the ridge portion. The flute includes: a first flute located at the first part and having a first helix angle; and a second flute located at the second part and having a second helix angle. The second helix angle is smaller than the first helix angle.

Provided is a method for manufacturing a sintered component, which can suppress occurrence of edge chipping when a through-hole is formed in a powder-compact green body and also has a good productivity. The method for manufacturing a sintered component includes a molding step of press-molding a raw material powder containing a metal powder and thus fabricating a powder-compact green body; a drilling step of forming a hole in the powder-compact green body using a drill; a sintering step of sintering the powder-compact green body after drilling, wherein the drill used for drilling has a circular-arc shaped cutting edge on a point portion thereof.

A drill includes a body. The body includes a first cutting edge, and a second cutting edge apart from the first cutting edge to the back end side relative to the first cutting edge and formed in a recess traversing an outer peripheral portion of the body. In a side view of the body in a first direction in which a distance between a center axis of the body and a first outer end of the first cutting edge is seen the longest, a second outer end of the second cutting edge is located at the center axis side relative to the first outer end of the first cutting edge.

A boring tool may include a coupling portion for interfacing with a powered driver, a shank operably coupled to the coupling portion, a cutting portion operably coupled to the shank, and a cutting portion. The cutting portion may be defined by a plurality of helical cutting flutes. The cutting tip may be operably coupled to a distal end of the cutting portion relative to the shank. The coupling portion, the shank, the cutting portion and the cutting tip may all share an axis. The cutting tip may include an inner portion and an outer portion. The inner portion may be defined by inner faces bisected by the axis and extending a first radial distance away from the axis to define a first point angle between the inner faces. The outer portion may be defined by outer faces extending from respective ones of the inner faces at the first radial distance to a second radial distance equal to a radius of the cutting portion to define a second point angle between the outer faces, and the second point angle may be less than the first point angle.

Drill for drilling in hard materials, including a drill head having a rotational axis, wherein the drill head includes an apex aligned with the rotational axis and centre point cutting edges radially extending and receding from the apex. A first one of the centre point cutting edges and a second one of the centre point cutting edges have a different radius and/or are receding at least for a part at a different rate. A drill for drilling in hard materials, including a drill head having a rotational axis. The drill head includes a centre point aligned with the rotational axis and main cutting edges radially extending from the centre point, wherein each of the main cutting edges deviates from a radial.

The invention relates to a drill comprising a drill tip, wherein the drill tip comprises at least one main cutting edge having a cutting corner, from which the main cutting edge extends to a center, wherein the drill tip comprises at least one additional cutting edge having an additional cutting corner, from which the additional cutting edge extends in the direction of the center, wherein the additional cutting edge is formed only on an outer portion of the drill tip and is thus shorter than the main cutting edge, wherein the additional cutting corner projects beyond the cutting corner.