A drill bit for use in forming holes in a printed circuit board (PCB) is disclosed. The drill bit includes a drill bit body having: a drill bit tip at a first end of the drill bit body; a flute winding about the drill bit body in a helix, wherein a helix angle of the flute is between 44 and 46 degrees in the vicinity of the first end and increases with increasing distance from the first end to between 49 and 51 degrees; and a land width of between 0.08 and 0.1 millimeters.

A drill (1) based on an embodiment of the present invention is equipped with: a first chip discharge flute that is provided on an outer periphery of a drill body and spirally extends around a rotational axis from a first cutting edge toward a rear end of the drill body; a second chip discharge flute that is provided on the outer periphery of the drill body and spirally extends around the rotational axis from a second cutting edge toward the rear end of the drill body; and an auxiliary flute that is provided on the outer periphery of the drill body and extends along the second chip discharge flute on a front side in a rotating direction of the rotational axis, wherein a rear end of the second chip discharge flute extends further toward the rear end of the drill body than the first chip discharge flute.

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.

A drill bit includes a body having a first end, a second end, an axis of rotation defined through the first and second end, and a body flute that extends along the axis of rotation at a helix angle. The drilling tool also includes a cutting head attached to the second end of the body. The cutting head includes a first land, a second land, and a cutting head flute. The cutting head flute is defined between the first land and the second land. The cutting head flute extends along the axis of rotation at the helix angle such that the body flute and the cutting head flute form a continuous flute.

A drill with a drill flute (12) includes symmetrical fluted lands (20) helically extend around a core, wherein grooves (18) remain between the fluted lands, said grooves having a width (72) that exceeds the spine thickness or width (24) of the fluted lands (20), and wherein the grooves (18) comprise a convex core reinforcement (22) at the groove bottom thereof. The width (24) of the fluted lands (20) at the drill head side end (16) is smaller than at the shank side end (14) of the drill helix (12), and at least increases in certain areas. The core reinforcement (22) at the drill head side end (16) is more convex than at the shank side end (14), thus has larger radii (40, 42).

A step drill bit can include a cutting head defining a longitudinal axis and multiple steps having different effective diameters. First and second cutting edges can be formed in the cutting head. The first cutting edge and the second cutting edge can be arranged such that the bit is asymmetric in a plane perpendicular to the longitudinal axis relative to a plane containing the longitudinal axis. The step drill bit can further include one or more flutes. Each flute can define a groove in the cutting head that extends along a helical path about the longitudinal axis. Each flute can have a variable helix angle such that the angle of the helix about the longitudinal axis changes at one or more points along the length of the flute.

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.

The invention relates to a rotary tool (2), in particular a drill, having a cutting part (10) that extends in a longitudinal direction (8) from a clamping shank (6) arranged in a rearward region (22) to a tool front (12) arranged in a forward region (20), and in which helically running chip flutes (14) and continuously helically running coolant channels (36) are fashioned, such that an exit opening (42) of each coolant channel (36) is arranged in the respective chip flute (14), wherein the chip flutes (14) are each shaped with an angle of twist () varying in the longitudinal direction (8) such that, in the forward region (20) facing towards the tool front (12), the respective coolant channel (36) is intersected by the respective chip flute (14) so as to fashion the exit opening (42).

A cutting element for use in a cutting operation, comprising a cutting edge (CE) capable of cutting out material from a workpiece during the operation, to form therein a workpiece corner of angle alpha. There exists at least one view of the cutting edge in which a portion of the cutting edge is delimitable by a first (L1) and a second (L2) line oriented tangentially to the portion of the cutting edge portion at respective tangency points A and B. The lines form therebetween a cutting angle corresponding to the workpiece corner angle alpha and have a vertex 0. For a bisector of the cutting angle intersecting the portion of the cutting edge at the point C, the projection C of the point C of the portion of the cutting edge on a line OL passing through the vertex 0 perpendicularly to the plane of the one view is located between projections A1 and B of the respective points A and B of the portion of the cutting edge on the line OL.

A method of manufacturing a drill bit includes providing a piece of bar stock having a first end, a second end opposite the first end, and an axis of rotation extending centrally through the bar stock between the first and second ends, cutting the first end of the bar stock to form a first tip angle at an oblique angle measured through the axis of rotation, cutting the first end of the bar stock at a second tip angle measured through the axis of rotation to form first tip surfaces and second tip surfaces. The first tip surfaces have the first tip angle and the second tip surfaces have the second tip angle. The second tip angle is smaller than the first tip angle. Finally forming a flute in the bar stock between the first and second ends and forming a shank at the second end of the bar stock.