A drill bit includes a body having a first end, a second end, and an axis of rotation extending centrally through the body from the first end to the second end. The drill bit also includes a shank adjacent the second end. The drill bit further includes a cutting head adjacent the first end. The cutting head includes a pilot tip and a cutting portion. The cutting portion has first tip surfaces and second tip surfaces on opposite sides of the pilot tip. Each first tip surface extends radially outward from the pilot tip to a corresponding second tip surface. The first tip surfaces define a first tip angle through the axis of rotation that is less than 180 degrees. The second tip surfaces define a second tip angle through the axis of rotation that is smaller than the first tip angle.

According to one implementation, a drill includes the first cutting edges, the second cutting edges and a deflection reducer. The first cutting edges drill a prepared hole to a workpiece. The first cutting edges are formed in a tip side of the drill. The first point angle and each first relief angle of the first cutting edges continuously or intermittently decrease from the tip side toward a rear end side of the drill. The second cutting edges finish the prepared hole. The second cutting edges are formed at positions away in the rear end side from the first cutting edges. The second cutting edges have the second relief angles at a maximum diameter position. The deflection reducer reduces deflection of the second cutting edges. The deflection reducer is formed between the first cutting edges and the second cutting edges. The deflection reducer is inserted into the prepared hole.

When forming a first preliminary flute on a PCD layer of a columnar body, electrical discharge machining is performed by setting the electrode orientation so that the first twist angle is α. Next, when forming a second preliminary flute on a substrate of the columnar body and a round bar, the grinding process is performed by setting the grinding orientation and direction for a diamond whetstone so that a second twist angle is larger than the first twist angle.

A drill body is provided which includes a flow hole capable of appropriately supplying a cutting region with a cutting fluid while securing stiffness of a leading end part. The drill body includes: a body part which extends in a rod shape from a base end part toward a leading end part; a discharge groove which is provided around a central axis of the body part in order to discharge chips; a fluid hole which is provided such that at least a part thereof passes through an inside, of the body part, of an inter-groove solid part of the discharge groove and which causes a fluid to flow from a side of the base end part toward a side of the leading end part; and a mounting part which is provided in the leading end part and which is for mounting a removable cutting edge member, wherein the mounting part has a recessed part which is provided along the central axis of the body part from an end surface of the leading end part, and a hole cross section of the fluid hole changes from a circular shape to a non-circular shape which is longer in a circumferential direction than in a radial direction in an axial cross section of the body part midway along a path of the fluid hole from the base end part toward the leading end part and assumes a non-circular shape in a portion which passes a side part of the recessed part.

A drill body is provided which includes a flow hole capable of appropriately supplying a cutting region with a cutting fluid while securing stiffness of a leading end part. The drill body includes: a body part which extends in a rod shape from a base end part toward a leading end part; a discharge groove which is provided around a central axis of the body part in order to discharge chips; a fluid hole which is provided such that at least a part thereof passes through an inside, of the body part, of an inter-groove solid part of the discharge groove and which causes a fluid to flow from a side of the base end part toward a side of the leading end part; and a mounting part which is provided in the leading end part and which is for mounting a removable cutting edge member, wherein the mounting part has a recessed part which is provided along the central axis of the body part from an end surface of the leading end part, and a hole cross section of the fluid hole changes from a circular shape to a non-circular shape which is longer in a circumferential direction than in a radial direction in an axial cross section of the body part midway along a path of the fluid hole from the base end part toward the leading end part and assumes a non-circular shape in a portion which passes a side part of the recessed part.

A drill bit includes a drill bit head, a multi-strand helix made up of three or more helix ribs, and a shank end along a drill bit axis. The multi-strand helix is made up of a conveyance area, a helix gradient, and a pitch. The helix ribs extend parallel to the drill bit axis in a first area adjacent to the drill bit head and a second area adjacent to the shank end.

A drill bit includes a drill bit head, a multi-strand helix made up of three or more helix ribs, and a shank end along a drill bit axis. The multi-strand helix is made up of a conveyance area, a helix gradient, and a pitch. The helix ribs extend parallel to the drill bit axis in a first area adjacent to the drill bit head and a second area adjacent to the shank end.

The invention relates to a method and an apparatus for producing a rod- or pipe-shaped intermediate product provided with an end face (106) from a semi-finished connecting element (102) made of metal, in particular an insertion end of a drill or chisel attached in an axially movable manner in the chuck of a hammer drill, the connecting element (100′) having at least one rotary entrainment surface (162, 164) and at least one locking depression (122, 124), the locking depression (122, 124) being preferably embodied as a locking groove, a semi-finished connecting element (102) being provided, the at least one rotary entrainment surface (162, 164) being formed in the semi-finished connecting element (102) by axially forcing the semi-finished connecting element (102) in the direction of the longitudinal axis (136) of the semi-finished connecting element (102) into a longitudinal die opening (204) of a die (202), or being embossed in the semi-finished connecting element (102) by radially applying at least one movable forming body (206), and the at least one locking depression (122, 124) being embossed by radially applying at least one or multiple forming bodies (206) that are movable in the same die (202).

The invention relates to a method and an apparatus for producing a rod- or pipe-shaped intermediate product provided with an end face (106) from a semi-finished connecting element (102) made of metal, in particular an insertion end of a drill or chisel attached in an axially movable manner in the chuck of a hammer drill, the connecting element (100′) having at least one rotary entrainment surface (162, 164) and at least one locking depression (122, 124), the locking depression (122, 124) being preferably embodied as a locking groove, a semi-finished connecting element (102) being provided, the at least one rotary entrainment surface (162, 164) being formed in the semi-finished connecting element (102) by axially forcing the semi-finished connecting element (102) in the direction of the longitudinal axis (136) of the semi-finished connecting element (102) into a longitudinal die opening (204) of a die (202), or being embossed in the semi-finished connecting element (102) by radially applying at least one movable forming body (206), and the at least one locking depression (122, 124) being embossed by radially applying at least one or multiple forming bodies (206) that are movable in the same die (202).

A method for manufacturing a high-torque hexagonal drill shank includes: firstly producing an air module, wherein the lower end of the air module is inserted into a molding cavity of a mold, a high-pressure air is injected into the air module, and the surface of the air module is provided with a plurality of air outlets; evenly mixing metal powder and an organic binder together; injecting obtained particulates in a heating-plasticizing state into the molding cavity by an injection molding machine to solidify and form a hexagonal drill shank blank; forming a non-cylindrical cavity inside the hexagonal drill shank blank under the action of the air module; removing the binder in the hexagonal drill shank blank by thermal decomposition; and, finally, obtaining a high-torque hexagonal drill shank by sintering and densifying.