The invention relates to a four-edged drill having two long main cutting edges, arranged in a point-symmetric manner with regard to the axis of rotation, which each extend from an outer circumferential cutting corner to a chisel edge in the middle of the drill tip, and two short main cutting edges, arranged in a point-symmetric manner with regard to the axis of rotation, which each extend from an outer circumferential cutting corner in the direction of the middle of the drill tip. According to the invention, each long main cutting edge has an outer partial cutting edge, extending from the cutting corner as far as a shoulder, and an inner partial cutting edge, extending from the shoulder as far as the chisel edge, said inner partial cutting edge having a greater cutting height (x) than the outer partial cutting edge and the short main cutting edges.

The invention relates to a single-lip drill with an inner and an outer rake face. Very good hole straightness deviation values and endurance are obtained with the ground face according to the invention.

A method for producing a cutting tool with a cutting edge that is formed at least in sections by an end face and a flute comprises the following sequence: Processing of the end face by means of grinding, and polishing of the flute by means of a flute polishing. Here, the flute polishing is carried out by means of a polishing wheel, wherein the polishing wheel is guided during the polishing in such a way that it is moved over the cutting edge and, at least in sections, a final edge rounding on the cutting edge is produced. Further, a cutting tool is disclosed that has been produced according to such a method.

An auger bit for cutting holes. The auger bit includes a body made of a first material. The body has a first end, a second end configured to be coupled to a power tool, a flute, and a longitudinal axis extending centrally through the body. The auger bit also includes a cutting tip made of a second material different from the first material. The cutting tip is coupled to the first end of the body. The cutting tip includes a first shoulder having a first spur, a first main cutting edge, and a first side cutting edge. The cutting tip also includes a second shoulder opposite the first shoulder and having a second spur, a second main cutting edge, and a second side cutting edge. The cutting tip further includes a center spur positioned between the first shoulder and the second shoulder and on the longitudinal axis.

A drill structure comprises a shank part and a bit part. A web is formed on the front end of the bit part. Two sides of the web are tilted backward to form two cutting faces. At least one chip-discharge groove is formed on the surface of the bit part. Each cutting face includes a primary cutting face and a secondary cutting face. The thickness of the prismatic web edge of at least one primary cutting face is smaller than the outer-side width of the primary cutting face. An auxiliary cutting face is extended to the wall of the flute from the cutting edge of the primary cutting face and a portion of a blade back of the secondary cutting face of another cutting face. The present invention decreases the drilling resistance during drilling a hole and increases the service life of the drill bit.

The negative land includes: a first region in which a space between the upper cutting edge and the lower cutting edge becomes wider toward the outer circumferential surface; and a second region which is continuous to the first region and in which the space becomes wider toward the rotation axis. In a cross section perpendicular to the rotation axis, the rake face includes a return face continuous to the outer circumferential surface, the return face being recessed opposite to a rotation direction of the drill. When a first boundary represents a boundary between the outer circumferential surface and the first region and a second boundary represents a boundary between the first region and the second region, a length of the first boundary is larger than a length of the second boundary in a direction parallel to the rotation axis. The second boundary is continuous to the return face.

Disclosed is a hole cutter capable of reducing a cutting load applied to a carbide tip during hole machining and improving cutting efficiency and workability. The hole cutter includes a cylindrical body, and a plurality of carbide tips disposed along an edge of the body. The carbide tips include a first carbide tip, a second carbide tip, and a third carbide tip. Assuming a circle which has a center coinciding with the body center and is in contact with a sharp tip of an upper surface portion of the first carbide tip, the second carbide tip is formed so that the sharp tip of an upper surface portion thereof is positioned at an inner region of the circle, and the third carbide tip is formed so that the sharp tip of an upper surface portion thereof is positioned at an outer region of the circle.

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.

A cutting head rotatable about a first axis, comprising an intermediate portion and a tip portion. The intermediate portion has a plurality of leading edges defining a cutting diameter, and the tip portion has an axially forwardmost tip point and a plurality of front surfaces with outer and inner cutting edges. An outer rake surface adjacent to each outer cutting edge has a positive outer rake angle, and an inner rake surface adjacent to each inner cutting edge has a negative inner rake angle. Each outer rake surface is disposed on a head flute intersecting one of the leading edges, and each inner rake surface is disposed on a gash intersecting one of the head flutes. Each gash extends to a gash path end point located a first distance axially rearward of the tip point, and the first distance is greater than thirty percent of the cutting diameter.

Orthopedic systems and methods for installing an implant and/or boring a bone bicortically. The system may include a drill having a proximal boring portion configured to bore a larger hole in a bone more efficiently when the drill rotates in a first direction compared to an opposite second direction, and a distal boring portion configured to bore a smaller hole in the bone more efficiently when the drill rotates in the second direction. The implant may be configured to be implanted at least partially in the bone, such that a first region of the implant is located in the larger hole and a second region of the implant is located in the smaller hole. In an exemplary method, the larger hole and the smaller hole may be bored in the bone's near cortex and far cortex, respectively, by a shaft and a nose of the drill rotated in opposite directions.