A twist drill and an exchangeable head for a twist drill, the twist drill extending along a central axis of rotation and having a front end formed as a drill point with two cutting edges and at least two clearance surfaces. Two helical chip flutes conduct chips away from the cutting edges. Each cutting edge extends in a transition between the clearance surfaces. One of the chip flutes extends from an inner position adjacent to the central axis to a peripheral envelope surface and has a main portion closest to the peripheral envelope surface. Each chip flute is delimited by a side surface including a main rake face, which extends rearward from the main portion of the cutting edge. The cutting edges are contained in an imaginary conical surface, such that the twist drill is operable to generate a bottom profile having the shape of an inverted cone.

A metal drilling tool comprising includes a middle axis, a front side and an opposite end, with at least two cutting edges arranged in a region of the front side, a first free surface being associated with each cutting edge. The at least two cutting edges lie on an imaginary first conical surface arranged concentrically in relation to the middle axis, with a first conical angle that opens up towards the opposite end and reaches a maximum of 180°. A centering section includes at least three edges, at least three side surfaces and an imaginary base surface. At least two of the edges lie on an imaginary second conical surface which is arranged concentrically in relation to the middle axis and has a second conical angle that opens up towards the opposite end. The second conical angle is smaller than the first conical angle, such that the imaginary second conical surface, seen from the opposite end, projects opposite the front surface.

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′.

The invention relates to single-lip drills and double-lip drills, in which one or more depressions are formed in the rake face. The depressions according to the invention are arranged in the longitudinal direction of the tool at a distance from the cutting edge and have a positive influence on chip breaking.

The invention relates to a single-lip drill and a double-lip drill having a plurality of chip-forming devices or depressions in the rake face which are arranged in succession and at a distance from one another. As soon as a cutting edge and/or the associated chip-forming device or the associated depression is worn, the deep hole drill according to the invention can be reground using simple means.

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 drill is rotatable about a central axis. The drill includes a central axis, a front end and a rear end opposite to each other in a direction along the central axis, an outer peripheral surface, a cutting edge formed at the front end and extending from the outer peripheral surface toward the central axis, a flank face contiguous with the cutting edge, a flute formed on the outer peripheral surface and extending spirally around the central axis from the front end toward the rear end, and a thinning rake face contiguous with the flute. The cutting edge has a main cutting edge extending from the outer peripheral surface and a thinning cutting edge contiguous with an end of the main cutting edge away from the outer peripheral surface. The flute includes a main rake face contiguous with the main cutting edge from the opposite side of the flank face.

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 trepanning apparatus, including a shaft portion extending along a longitudinal axis; an annular cutter portion; and a connecting portion extending axially between the shaft portion and the cutter portion, the connecting portion including a pair of arms each having a front end connected to the cutter portion and a rear end connected to the shaft portion, the arms circumferentially spaced from one another about the longitudinal axis to provide diametrically opposed first and second openings, a first plug retaining surface defined by a first portion of the rearward end of the cutter portion having a first circumferential extent bounded by the front ends of the arms, and a second plug retaining surface defined by a second portion of the rearward end of the cutter portion having a second circumferential extent bounded by the front ends of the arms, the first circumferential extent greater than the second circumferential extent.

A deburring tool (7) for deburring of edges of transverse recesses (3, 3a-i), which diverge from a main borehole (2), consisting of a shaft (8, 9) driven to turn about the tool axis (11), which is deployable and retractable in the forward feed direction into the main borehole, and on the lower end of which at least one knife window (26) is arranged, in which at least one spring-loaded knife (10, 10′, 10″, 10′″, 10″″) is arranged roughly perpendicular to the tool axis (11), so as to be shiftable, which on its front end has at least one cutting edge (10a, 10b) which encounters the edge of the transverse recess (3, 3a-i), and deburrs same, wherein the knife (10, 10′, 10″, 10′″, 10″″) consists of two cutting edges (10a, 10b) opposite in the rotational direction (12, 13), which act to cut equally for the right and left passes (12, 13), with one cutting edge (10a) being configured to cut for the rightward pass (12), both in forward motion (38a) and in rearward motion, and the other cutting edge (10b), being configured to cut for the leftward pass (13), both in forward motion (38a) and in rearward motion, and that the two cutters (10a, 10b) with their cutting edges are placed at a slant and with arch shape at an angle between 0° and 90°, but preferably between 5° and 45° to the tool axis (11) and thus to the longitudinal axis (2a) of the main borehole (2).