A drill bit configured for use with a rotary power tool including a chuck. The drill bit includes a shank including a first end and a second end, and a paddle that extends from the second end of the shank. The paddle includes a first face including a concave portion, a second face opposite the first face and the second face including a convex portion opposite the concave portion, a cutting surface, a cutting edge located at an end of the cutting surface, a relief angle defined by the cutting surface, and an angled rake face adjacent the cutting surface that defines a rake angle that is between about 5 degrees and about 45 degrees.

A one-piece cutting head for a drill bit includes a main cutting edge that extends between radial extremities of the cutting head. The main cutting edge is disposed between main rake surfaces and main relief surfaces. Each main rake surface includes one or more rake facets, and each main relief surface includes one or more relief facets. Adjacent rake facets and relief facets define a primary transverse edge therebetween that extends away from the main cutting edge. The cutting head further includes a plurality of side cutters that are transverse to the main cutting edge and that propagate from the primary transverse edge to a radial extremity of the cutting head. Each side cutter includes a side cutting edge between a side cutting rake facet and a side cutting relief facet.

The present disclosure relates to cutting tools and cutting inserts in general, and more particularly to the specific shapes of cutting edges on cutting tools and cutting inserts. In an embodiment, a cutting tool with a cutting edge formed as a sinusoidal curve is provided. In an embodiment, a rotary drill bit including a cutting insert comprising a sinusoidal curve is provided.

A drilling tool, in particular a reamer, for drilling out a workpiece core bore to a nominal diameter by means of a main blade formed on a drill body is disclosed. The main blade has a radially external cutting edge which extends along a drill-body longitudinal axis as far as a blade corner arranged at the drill tip, wherein during the drilling-out operation, the drilling tool is drivable into the workpiece core bore with a rotary movement and a feed movement. The drilling tool has at least one groove blade which is arranged so as to precede the blade corner of the main blade in the direction of rotation of the tool. During the drilling-out operation, the groove blade produces a groove in the inner wall of the core bore drilling, the blade corner of the main blade being guided in the groove with an at least reduced cutting load.

According to one implementation, a drill that drills at least one of a composite material and a metal is provided. A web thickness at least at a tip of the drill is not less than 5% and less than 25% of at least one diameter of the drill. Further, according to one implementation, a method of manufacturing a drilled product is provided. The drilled product is manufactured by drilling a workpiece using the above-mentioned drill. The workpiece is made of the at least one of the composite material and the metal.

In an embodiment, a drill has an elongated shape and a rotation axis. The drill includes a drilling portion, a shank portion, and a tapered portion. The shank portion includes a first helical flute and a first cutting edge. The tapered portion is located between the drilling portion and the shank portion. The tapered portion includes a second helical flute, a second cutting edge, a chamfered part, and a connection part. The chamfered part is getting smaller gradually as moving toward the first end side. The connection part has a curved surface and connects the second cutting edge and the drilling portion. A ratio of w/L is 0.0015-0.5 where L is a length of the second cutting edge in a front view of the first end, and w is a width of an outer peripheral end of the chamfered part in a direction parallel to the rotation axis.

A drill bit has a shank, an intermediate shaft, and a cutting head and defines a longitudinal axis. The cutting head has a body having a front end, a rear end, and a peripheral sidewall, a primary cutting insert and a pair of auxiliary cutting inserts. The primary cutting insert is cross-shaped with a central portion with a cutting tip and four cutting arms each with a cutting edge extending radially outward from the central portion past the peripheral sidewall. The auxiliary cutting inserts are spaced radially outward from the central portion and circumferentially from the radial cutting arms, and have a cutting edge extending radially outward past the peripheral sidewall. A pair of primary dust egress slots and a pair of auxiliary dust egress slots are formed in the peripheral sidewall and configured to channel debris from the front end to the rear end of the body.

A drill includes a cutting edge. The cutting edge has a point angle which is continuously decreased from a center-position point angle A (herein, 0<A<180) at a center position to a maximum-diameter-position point angle of 0 at a maximum diameter position. The cutting edge has a relief angle which is continuously decreased from the center position to the maximum diameter position. The cutting edge of the drill has a relief angle at the maximum diameter position. Hence, the cutting edge also serves as a cutting edge for reaming. The ridgeline and relief face of the cutting edge have no corner, thereby providing good wear resistance.

A cutting member comprising a cutting edge (S.sub.1,S.sub.2,S.sub.i) defining a cutting envelope and configured for removing material from a workpiece leaving therein a corner of angle . The cutting edge comprises a first cutting segment (S.sub.1) and a second cutting segment (S.sub.2) spaced from the first cutting segment (S.sub.2). Respective first and second imaginary tangents (T.sub.1,T.sub.2) of the first and second cutting segments (S.sub.1,S.sub.2) intersect one another at point O located outside the cutting envelope, forming an angle corresponding to angle , thereby defining a cutting frame at least a portion of which extends beyond the cutting envelope. The cutting edge further comprises an adjoining cutting segment (S.sub.i), extending between and bridging the first cutting segment (S.sub.1) and the second cutting segment (S.sub.2), and at least partially contained within the cutting frame. The cutting member further comprises at least one auxiliary cutting element (AT.sub.1,AT.sub.2) comprising an auxiliary cutting edge (CE,CE) extending generally along one of the imaginary tangents (T.sub.1,T.sub.2) and beyond the cutting envelope. The auxiliary cutting edge (CE,CE) does not intersect the other of the imaginary tangents (CE,CE) and/or a bisector (B) of the angle .

A drill according to an embodiment of the present invention has a pair of main cutting edges positioned at a front end of a drill body, a pair of first chisel edges each extending from the pair of main cutting edges toward a rotation axis, and a second chisel edge positioned between the pair of first chisel edges and intersecting with the rotation axis of the drill body. When viewing a locus of rotation of the pair of first chisel edges and a locus of rotation of the second chisel edge in a cross section taken so as to include the rotation axis, the respective locus of rotation of the pair of first chisel edges have a rectilinear shape, and respective imaginary straight lines obtained by extending the locus of rotation of the pair of first chisel edges toward the rotation axis are positioned further to a rear end side of the drill body than the locus of rotation of the second chisel edge.