Drills and methods of removing material using drills are disclosed. Drills may include a plurality of lands that extend to a cutting edge, where adjacent lands are separated by flutes comprising a base contour arranged in a generally helical configuration along a centerline axis of a drill body. The drill also includes a plurality of contoured drill points each having a linear portion that extends towards an outer diameter of the drill body, and an arcuate portion that extends from the linear portion and towards a chisel of the drill body. The drill further includes a plurality of gash contours positioned within the plurality of flutes. The gash contours extend from the chisel of the drill body, and the gash contours are oblique to the base contours of the flutes.

A drill bit for drilling into masonry or rock includes a drilling head at its forward end, a clamping shank at its rearward end, and a helical conveying portion extending between the drilling head and the shank. The helical conveying portion includes at least two helically extending flutes separated by at least two helically extending webs. The helical conveying portion has a changeover portion, a pre-changeover portion between the drilling head and the changeover portion, and a post-changeover portion between the changeover portion and the shank. In the pre-changeover portion, the flutes have a pre-changeover pitch, the first web has a first pre-changeover web width α, and the second web has a second pre-changeover web width α′. In the post-changeover portion, the flutes have a post-changeover pitch, the first web has a first post-changeover web width β, and the second web has a second post-changeover web width β′. The post-changeover pitch is greater than the pre-changeover pitch, the first post-changeover web width β is less than the first pre-changeover web width α, and the second post-changeover web width β′ is greater than the second pre-changeover web width α′.

Provided are a hole formation method enabling the formation of a high-quality hole even when a workpiece material is a difficult-to-machining metal material or a fiber-reinforced composite material and a drill bit used in the method. A drill bit includes at least one cutting edge and a face (a leading flank and a trailing flank) positioned in the vicinity of the cutting edge, and on the face, a recess exhibiting a prescribed planar shape (groove) is provided. A hole formation method includes a hole formation step of machining a portion to be processed of a workpiece material by means of drilling to form a hole while a lubricant material for assisting machining process is in contact with the portion to be processed, and in the hole formation step, the drill bit is used.

A three-flute drill includes a body, discharge grooves, cutting edges, thinning edges and gash portions. The discharge grooves are provided in an outer peripheral surface of the body. The cutting edges are provided on ridge sections between inner faces of the discharge grooves and flanks of the body. The thinning edge extends from an end of the cutting edge toward a radially inner side. The gash portion includes an R portion and a straight portion. A first ridge line between the R portion and the flank extends while curving toward a rotation direction, from an end of the thinning edge toward a radially outer side. A second ridge line between the straight portion and the flank extends linearly from an end of the first ridge line toward the radially outer side, and connects to the discharge groove further to the radially inner side than the outer peripheral surface.

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.

A tool holder for a lathe having a spindle permits improved arrangement of tools on a turret to maximize the allowable workpiece outer diameter for a given tool. A Z-axis feed mechanism moves the spindle and the turret relative to each other in a Z-axis direction along a center axis of the spindle, while an X-axis feed mechanism moves the spindle and the turret relative to each other in an X-axis direction orthogonal to the Z-axis direction. A plurality of tool holders is attached to the turret, each having a tool holding part. At least one of the tool holders holds the tool at a holding position such that, when indexed to a machining position by rotation of the turret, a cutting-edge reference point of the tool is offset with respect to an X-Z plane including a center axis of the turret.

A drilling tool comprising a tool holder that extends along a central axis and comprises a first cutting insert receptacle having a first abutment surface oriented parallel to the central axis. The drilling tool further comprises a first cutting insert that is fixed in the first cutting insert receptacle and abuts with one of its sides against the first abutment surface, wherein an axial portion of the first cutting insert projects axially beyond an end face end of the tool holder, and wherein the first cutting insert comprises in the axial portion a first main cutting edge that is inclined with respect to a first imaginary plane, which is oriented orthogonally to the central axis and arranged at the end face end of the tool holder, so that a radially outer end of the first main cutting edge is spaced a larger distance from the first imaginary plane than a radially inner end of the first main cutting edge and the first main cutting edge does not intersect the first imaginary plane, and wherein the first main cutting edge touches or intersects a second imaginary plane that is spanned by the central axis and oriented orthogonally to the first abutment surface.

A drilling insert has a central portion with a central axis, and three circumferentially spaced tip portions. Each tip portion has a first axis and two diverging first cutting edges with radially outermost cutting points defining a first circle lying on a tip plane perpendicular to the first axis and having a first cutting diameter. In a view along one of the first axes, a second circle having a second diameter circumscribes the drilling insert, and the first cutting diameter is at least sixty percent of the second diameter. A cutting tool rotatable about a tool axis with a tool cutting diameter includes the drilling insert, and a second cutting insert having a second cutting edge. One of the tip portions is operative having its first axis coaxial to the tool axis, and the second cutting edge extends radially outward of the first cutting diameter.

A method for producing a cutting tool, in particular a drill bit, is specified wherein the cutting tool has a front end (F) at the front and a rear end (R) toward the rear, wherein a tool tip is formed on the front end (F), a point thinning is ground at the tool tip with a grinding tool, the point thinning being ground to be narrower toward the front than toward the rear. The point thinning is ground with a constant point thinning angle (AW). Furthermore, a corresponding cutting tool is specified.

A drill bit includes an elongated shaft having an outer surface forming plural lands and spaces between the lands forming a helical flute; a shank located at a first end of the elongated shaft, the shank configured and arranged to engage the drill bit in a tool; a head located at an opposing end of the elongated shaft from the shank, the head including a first cutting arm and a second cutting arm, the first cutting arm including a first cutting portion having a first leading cutting edge, the second cutting arm including a second cutting portion having a second leading cutting edge; and wherein the first cutting arm includes a first groove extending through the first leading cutting edge and the second arm includes a second groove extending through the second leading cutting, the first and second grooves configured to cause shorter fibers, shavings or chips.