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.

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 drill structure includes a shank part and a flute part. A chisel edge is formed on the front end of the flute part and two primary relief faces with tile directions toward the shank part are symmetrically formed on the two sides of the chisel edge. Each primary relief face has a cutting edge, a knife-back edge, and an outer edge. The outer edges are respectively helically extended around the periphery of the flute part to form two helical cutting edges and two helical grooves. Two assist relief faces are respectively formed on the inner walls of the two helical grooves, and every assist relief face is connected with the cutting edge of one primary relief face and portion of the knife-back edge of another primary relief face. The drill structure can decrease the thickness of the chisel edge, reduces the resistance during drilling, and increases the life.

A bottom cutting step up reamer incorporates a shaft having a first end with attachment features adapted to be received in a chuck. A plurality of bottom cutting edges substantially perpendicular to the shaft are located at a second end distal from the first end. At least one step up land is provided proximate the plurality of bottom cutting edges and spaced toward the first end with a plurality of parallel cutting edges substantially parallel to the shaft.

A general-purpose multiple-cutting edge drill includes: a drill point (1); a drill body (2); margins (3) located on an outer wall of the drill body (2); two lips, wherein, if viewed from an axial direction, from out to inside, each of the two lips successively includes an outer cutting edge (11), an arc cutting edge (12) and an inner cutting edge (13); a chisel edge (14); outer peaks (15) formed by intersection of the outer cutting edges (11) and the arc cutting edges (12); a center peak (16) formed by intersection of two inner flank surfaces and two split surfaces. Moreover, an included angle between the inner cutting edges (13) ranges from 108 to 128, an included angle between the outer cutting edge (11) ranges from 130 to 140, and an included angle between the inner cutting edge (13) and outer cutting edge (11) ranges from 28 to 40.

A rotary cutting tool comprises 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 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.

The present drill point arrangement includes a first and second land defined by a first and second flute, with a first cutting tip and a second cutting tip formed on the first and second lands respectively. The first cutting tip being positioned a first radial distance and the second cutting tip being positioned a second radial distance, each measured from the axis of rotation. The second cutting tip is positioned next in cutting tip sequence to the first cutting tip, and the second radial distance of the second cutting tip is greater than the first radial distance of the first cutting tip. Optionally, the first cutting tip is positioned a first axial distance and the second cutting tip is positioned a second axial distance, each measured from the front tip, and the second axial distance is greater than the first axial distance.

A flat drill (1) with a shank (6) and a cutting part (8) with front-side main cutting edges (16), which each extend in a plane transversely to the drill axis (3) from a cutting edge corner (22) into the drill center. The flat drill (1) has exactly three main cutting edges (16), which converge at the drill axis (3).

An information handling system stores data associated with one or more drills bits for a backdrill operation of a printed circuit board. The system determines an XY axis tolerance for a via of the printed circuit board. Based on the XY axis tolerance and the signal speed, the system determines an effective Z axis tolerance for the backdrill operation. Based on the determined effective Z axis tolerance, the system determines a tip angle. The system provides the tip angle on a display device.