The invention relates to a rock drill comprising an insertion portion, a flute adjoined to the insertion portion, and a head portion adjoined to the flute, wherein the flute is of at least double-spiral configuration and correspondingly has at least two substantially spiral discharge grooves, to which respectively two substantially spiral flute webs forming the lateral groove walls are assigned. It is proposed that a constant spiral pitch is assigned to the first discharge groove, inclusive of the lateral groove walls thereof, along the drill longitudinal axis, and that at least one of the two flute webs assigned to the first discharge groove has or have along the drill longitudinal axis, at least in sections, a web spine width which changes, in particular, alternately.

In order to ensure good guidance of a drilling tool at the start of a drilling operation and at the same time ensure a reliable evacuation of a center chip, in the drill bit, in a tool flank adjoining a respective main cutting edge, an additional point thinning is recessed in the region of a transverse cutting edge, which additional point thinning, extending in a principal direction from the tool flank, merges, with a convex course, into a chip flute. As a result of the convex design, an as far as possible homogeneous, edge-free transition into the chip flute is obtained. Since the point thinning is additionally made, the tool flank, even in the rear end facing away from the cutting edge, remains at a front axial position, so that a second land is effective for a reliable guidance of the bore already at an axially front position.

A drill bit or boring tool having cutting edge that includes a pair of generally smooth curvilinear shaped portions that are positioned near the radial outer portions of the cutting edge and connected to one another by a pair of generally linear portions that traverse the longitudinal centerline of the tool.

A milling and boring tool with a tool shaft which comprises a center axis, at least one geometrically defined rough cutter and at least one geometrically defined finishing cutter, and the at least one rough cutter and the at least one finishing cutter respectively comprise a chip groove. The milling and boring tool is characterized in that the chip groove of the at least one finish machining cutter has an opposite twist than the chip groove of the at least one rough cutter.

A rotary tool comprising two coupling parts, namely a carrier and a cutting head in a front end surface. The carrier comprises a pin receptacle into which a coupling pin of the cutting head is inserted. In order to prevent pulling-out in an axial direction, stop surfaces are provided on the pin receptacle and on the coupling pin, said stop surfaces being effective in an axial direction. For a design that is as simple as possible, in particular with regard to grinding, each stop surface of the coupling pin is adjoined by a lateral surface which freely tapers off in the direction toward the end surface as viewed in the axial direction. In particular, the lateral surface constitutes a torque surface.

A drilling tool for producing drill holes includes a tip and a shaft arranged opposite the tip in a direction of a longitudinal axis of the drilling tool. The drilling tool has at least one geometrically defined cutting edge in the tip area, and has an expanded diameter trailing the tip in a longitudinal direction from the tip. The drilling tool has a first area with a first diameter that precedes the expanded diameter, and a second area with a second diameter, larger than the first diameter, that trails the expanded diameter. The drilling tool is distinguished in that the expanded diameter and/or the second area is/are embodied such that chips are produced in the area of the expanded diameter and/or in the second area when a workpiece is machined, chips consistent with those produced when a workpiece is machined with a geometrically undefined cutting edge.

The present invention relates to a drill bit structure which comprises a body. The body has a free end, an intermediate section and a connection end. The body comprises a first groove portion, a second groove portion, a third groove portion, a fourth groove portion and a fifth groove portion. The first groove portion is partially overlapped with the third groove portion from the free end. The second groove portion is partially overlapped with the fourth groove portion from the free end. After extending a preset axial distance from the free end, the first groove portion and the second groove portion are partially overlapped with each other by forming an intersecting protrusion. The fifth groove portion is extended from the intermediate section toward the connection end. The first, second, third and fourth groove portions are extended to the fifth groove portion.

A drill has a replaceable cutting head mounted to a shank in an interlocking fashion. The shank has a pocket with at least one flat, vertically-angled retention surface located closer to a rotational axis than at least one driving surface. Similarly, the cutting head has at least one vertically-angled retention surface located closer to the rotational axis of the drill than at least one driven surface. As a result of the relative locations between the surfaces with respect to the rotational axis, the stresses and fatigue imposed on the drill are minimized, thereby prolonging tool life.

A rotary cutting tool with an elongate body disposed about a longitudinal axis, the elongate body including a helical flute and a polycrystalline-diamond cutting tip. The cutting tip comprises an inner portion having an inner point angle and an outer portion having an outer point angle different from the inner point angle.

A twist drill for drilling composite materials includes a shank; a drill body; a drill tip having a cutting edge, a chisel edge, and a secondary chisel edge, wherein the secondary chisel angle of the drill tip is 145 to 165 and the point angle is 70 to 100; and a flute extending from the drill tip to the drill body. The flute has a constant helix, and the helix angle of the flute being selected from the range 45 to 55. A method of drilling a composite material comprising fibers uses the twist drill of the present embodiment. Suitably, the composite material is carbon fiber reinforced plastic or glass fiber reinforced plastic, and optionally being a laminate material such that the method comprises stack drilling. Embodiments achieve a combination of good hole quality, good tool life and good hole size spread.