In a drill, a negative hind is provided on a rake face, and a ridge line at an intersecting position of the negative land and a flank face, a ridge line at an intersecting position of the flank face and a margin, and a ridge line at an intersecting position of the negative land and the margin are convex faces in a longitudinal rectangular cross section. When a curvature radius of the convex face of a first ridge line at the intersecting position of the flank face and the negative land is 1, at curvature radius of the convex face of a second ridge line at the intersecting position of the flank face and the margin is 0.8 to 1.5 times the curvature radius of the first ridge line, and a curvature radius of the convex face of a fourth ridge line at the intersecting position of the negative land and the margin is 1.5 to 3.0 times the curvature radius of the first ridge line.

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 cutting head rotatable about a head axis has a cap portion and a mounting protuberance joined thereto. The cap portion has N cutting portions circumferentially alternating with N head flutes. The mounting protuberance has N circumferentially spaced apart engagement portions, each including a radially outward facing clamping surface and a torque transmission surface. In a cross-section taken in a head plane perpendicular to the head axis, a first imaginary circle having a first diameter circumscribes the N clamping surfaces, and N radially outermost torque points of the N torque transmission surfaces define a second imaginary circle having a second diameter. The second diameter is greater than ninety percent of the first diameter. A rotary cutting tool includes a tool shank extending along a shank axis and a head receiving pocket at a forward end thereof, and the cutting head is releasably secured in the head receiving pocket.

A rotary tool may include a body having a first part, a second part, a third part, a first cutting edge located at a first end, a flute extending from the first cutting edge toward a second end, and an outer peripheral surface. The outer peripheral surface in the third part may have a first portion. The third part may have a land face, and a second cutting edge located on a ridge line where a first portion and the land face intersect. The land face may have a first region in which a width increases from a side of the first end toward a side of the second end, and a second region that is located closer to the second end than the first region in which a width decreases from a side of the first end toward the second end.

In this drill, a wall face of a chip removal groove includes a first wall face having a concave curve shape and a second wall face having a straight line shape in a cross section orthogonal to an axis of the drill main body, an extension line of a straight line of the second wall face extends in a direction opposite to a drill rotation direction as the straight line of the second wall face goes to an outer periphery side of the drill main body with respect to a radius line connecting an outer peripheral end of the second wall face and the axis with each other, the cutting edge includes a first cutting edge having a concave curve shape and a second cutting edge having a straight line shape which intersects with the first cutting edge at an obtuse angle.

An auger includes a body having a first end, a second end opposite the first end, a stem that extends from the first end to the second end and defines an axis of rotation, and a flute helically wrapped around the stem. The auger also includes a shank at the first end of the body configured to be received by a power tool and a cutting head at the second end of the body. The cutting head includes a cutting edge, a spur, a feed screw with a thread, and a cutting face positioned adjacent the cutting edge. The cutting head defines a step at an interface with the body, and wherein the cutting head has a maximum diameter that is greater than a maximum diameter of the body.

A drill includes a drill body having a longitudinal axis, a front end, and a frontend portion and at least one flute in the front end portion. A cutting insert is mounted to the drill body in each flute of the at least one flute at the front end of the drill body. The at least one flute includes a plurality of grooves, concave surfaces of adjacent ones of the grooves intersecting to define a ridge separating the grooves.

A method for producing a drill shaft for a wet drill bit includes forming N, where N≥1, strip materials into a tubular body where the tubular body is integrally joined at strip edges of the strip materials by N connection welds. At least one strip material of the strip materials is provided with at least one recess before the integral joining of the strip edges.

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 body and a drill are disclosed. The drill body has a rotational axis and comprises a central chip flute extending along a periphery of the drill body. A central chip flute cross-section has a centre line extending in a plane extending perpendicularly to the rotational axis, and through the rotational axis. The central chip flute cross-section has a depth, as seen along the centre line, and a width as seen perpendicularly to the centre line. The central chip flute cross-section has a maximum depth Dp within a range of Dp=0.75×D/2 to Dp=0.90×D/2, and a maximum width W within a range of W=0.75×D/2 to W=0.90×D/2, and wherein the maximum width W extends symmetrically about the centre line.