A drill bit for a drill includes a body clearance extending helically along the drill bit, a margin also extending helically along the drill bit, adjacent to and projecting radially beyond the body clearance, and a flank at which the body clearance and the margin terminate at a tip of the drill bit. The margin has a variable width along its helical extension.

A step drill bit includes a body with a plurality of cylindrical steps of increasing diameter from a front end toward a rear end, a flute extending from the front end toward the rear end, and cutting edges at junctions between each step and the flute. A cutting insert with a hardness greater than the hardness of the body is coupled to the front end portion and at least partially defines a cutting head portion. The cutting head portion includes a center cutting tip, a cutting edge extending radially outward from the cutting tip, a rake face extending from the cutting edge toward the rear end portion, a relief face extending from the cutting edge in a circumferential direction opposite a rotational cutting direction of the drill bit, and a chip clearing recess in communication with the flute, with the rake face facing the chip clearing recess.

A drill has a body extended along a rotation axis from a first end toward a second end. The body has an outer peripheral surface, a cutting edge, a flank surface, and a flute. The cutting edge has a first cutting edge, a second cutting edge extended from the first cutting edge, and a third cutting edge extended from the second cutting edge. The flank surface has a first flank surface which is located along the first cutting edge and has a first clearance angle, a second flank surface which is located along the second cutting edge and has a second clearance angle, and a third flank surface which is located along the third cutting edge and has a third clearance angle. The second clearance angle is smaller than each of the first clearance angle and the third clearance angle.

A machining tool for producing or machining bores, respectively, with high positional and/or surface quality, comprising a tool axis and a tool carrier section, which carries at least one tool blade and at least one guide rail, which radially supports the tool carrier section on a bore wall. The guide rail can be set with respect to its radial position and with respect to its tilt relative to the tool axis by means of a setting means, which engages with a guide rail carrier. In order to put together a tool, which operates highly precisely and with little effort, the guide rail carrier is connected via a material joint to a section that is fixed to the tool, thus either to the tool carrier section or a component, which can be firmly connected thereto, and the material joint can be blocked by means of the setting means.

A rotary cutting tool is provided having a body and a fluid passage. The body has a shank portion and a cutting portion. The body extends lengthwise along a central axis between a shank end and a cutting end. The cutting portion includes a fluted section and a plurality of teeth extending axially outwardly from the fluted section at the cutting end. The fluted section includes a plurality of flutes disposed within an exterior surface of the fluted section. The cutting portion includes an internal cavity disposed within the fluted section and open to the cutting end. The internal cavity is defined by an interior wall surface. The cutting portion includes a plurality of channels disposed within the interior wall surface and open to the internal cavity. The fluid passage extends through the shank portion to the internal cavity.

A rotary cutting tool having a lengthwise extending central axis is provided. The tool includes a shank portion and a cutting portion. The cutting portion is connected to the shank portion, and includes a fluted section and a plurality of teeth. The fluted section includes a plurality of flutes disposed within an exterior surface of the fluted section. The cutting portion includes an internal cavity disposed within the fluted section and open to a cutting end. Each tooth includes a front side surface, an exterior side surface, an interior side surface, and an axial end surface. The front side surface intersects with the axial end surface to form an axial end cutting edge that extends radially between an outer radial tip and an inner radial tip, and the outer radial tip is disposed axially outside of the inner radial tip.

A rotary cutting tool cutting insert is provided that includes front, aft, exterior, and interior side surfaces, an axial end surface, and a base surface. The exterior side surface intersects with the front side surface. The interior side surface intersects with the front side surface. The axial end side surface intersects with the front side surface at an axial end cutting edge, with the exterior side surface at a first outer axial edge, and with the interior side surface at a second outer axial edge. The base surface intersects the front, exterior, and interior side surfaces and the aft surface. The base surface intersects the front side surface at an inner edge. An outer radial tip is disposed at a first heightwise distance from an inner edge, and an inner radial tip is disposed at a second heightwise distance from the inner edge.

A drill has two to four cutting edges each made of cemented carbide or polycrystalline diamond. Helical flutes are formed alternately with the cutting edges. X-shaped thinning has been applied to the cutting edges. A rake angle of the cutting edges is not less than 30 degrees and not more than 40 degrees. A clearance angle of the cutting edges is more than 0 degrees and not more than 8 degrees. The cutting edges each has a honed face by chamfer honing. A honing angle of the honed face is not less than ?3 degrees and not more than 8 degrees.