A drill bit includes a body having a first end, a second end opposite the first end, and an axis of rotation extending centrally through the body. The drill bit includes a cutting head with a cutting tip on the axis of rotation and a cutting portion. The cutting portion includes first tip surfaces on opposite sides of the axis of rotation and second tip surfaces on opposite sides of the axis of rotation. Each first tip surface extends radially outward from the cutting tip to a corresponding second tip surface. Each second tip surface extends from a corresponding first tip surface to an outer periphery of the body. The first tip surfaces define a first tip angle measured through the axis of rotation that is oblique. The second tip surfaces define a second tip angle measured through the axis of rotation that is smaller than the first tip angle.

A drill includes a leading end portion. The leading end portion is flat and has at least two cutting blades extending from a rotation center toward outside in a radial direction. The each cutting blade includes an arc-shaped portion. An inside linear portion is formed in a linear shape and connects to one end of the arc-shaped portion on the rotation center side. An outside linear portion is formed in a linear shape and connects to another end of the arc-shaped portion on an opposite side to the one end. The arc-shaped portion has a cutting edge provided with an arc-shaped portion chamfered surface. The inside linear portion and the outside linear portion each has a cutting edge provided with a linear portion chamfered surface. A drill axis direction width of the arc-shaped portion chamfered surface is smaller than a drill axis direction width of the linear portion chamfered surface.

According to one implementation, a drill includes the first cutting edges, the second cutting edges and a deflection reducer. The first cutting edges drill a prepared hole to a workpiece. The first cutting edges are formed in a tip side of the drill. The first point angle and each first relief angle of the first cutting edges continuously or intermittently decrease from the tip side toward a rear end side of the drill. The second cutting edges ream the prepared hole. The second cutting edges are formed at positions away in the rear end side from the first cutting edges. The second cutting edges have the second relief angles at a maximum diameter position. The deflection reducer reduces deflection of the second cutting edges. The deflection reducer is formed between the first cutting edges and the second cutting edges. The deflection reducer is inserted into the prepared hole.

A drill in which: a chip discharge groove is formed in an outer periphery of an edge portion serving as a leading end side portion of a drill body; and a cutting edge is formed in an intersecting edge between a rake surface of a leading end side region and a leading end flank of the edge portion, the drill comprising a margin portion, a shoulder portion and a web thinning portion, wherein: the cutting edge comprises, in order from a rotation center, a first cutting edge portion, a second cutting edge portion, a shoulder cutting edge portion, and a margin cutting edge portion; the honing width gradually decreases from the boundary P1 toward the position P2; and the conditions represented by expression (1): honing width of second cutting edge portion≤R1 and expression (2): 2.0<R1/R2<5.0 are satisfied.

An apparatus for selectively removing material from both an inner and outer circumference of an end of a tubular workpiece includes a cylindrical outer frame. A blade holder is affixed to the outer frame. The blade holder has a conical configuration with a base located adjacent a first rim of the outer frame and an apex located adjacent a second rim of the outer frame. At least one ID blade is carried by the blade holder and has an ID cutting edge oriented radially outward. At least one OD blade is carried by the blade holder and has an OD cutting edge oriented radially inward. A motive cap has a rim-coupling feature configured for selective engagement sequentially with the first and second rims of the outer frame, to selectively provide rotational motion to the outer frame and thus indirectly to the blade holder.

A drill bit includes a shank extending along a bit axis and a body with a proximal end adjacent the shank and a distal end opposite the proximal end. The body defines a plurality of axially stacked, progressively sized steps including a first step at the distal end and a terminal step at the proximal end. The drill bit also includes a flute in the body. The flute defines an elongated groove that extends from the distal end to the proximal end. The drill bit further includes a plurality of cutting edges formed in the body. Each cutting edge is disposed along one of the plurality of steps and defines a helix angle and a rake angle. The helix angle of the cutting edge at the terminal step is greater than the helix angle of the cutting edge at the first step. A ratio of the helix angle to the rake angle of the cutting edge at the first step is in a range from 0.5 to 2.4, and a ratio of the helix angle to the rake angle of the cutting edge at the terminal step is in a range of 0.9 to 1.7.

There is provided a machining assembly and cutting insert for machining metal or like workpieces, wherein the cutting insert body has a cutting end. The cutting end comprises at least one cutting edge and at least one cutting lip formed adjacent the at least one cutting edge. The at least one cutting lip includes at least one cutting protrusion and associated chip cutting edge to split the chip formed by the at least one cutting edge, for producing chips during machining which are of a width that is sufficiently reduced to allow proper evacuation or removal.

According to one implementation, a drill includes the first cutting edges, the second cutting edges and a deflection reducer. The first cutting edges drill a prepared hole to a workpiece. The first cutting edges are formed in a tip side of the drill. The first point angle and each first relief angle of the first cutting edges continuously or intermittently decrease from the tip side toward a rear end side of the drill. The second cutting edges finish the prepared hole. The second cutting edges are formed at positions away in the rear end side from the first cutting edges. The second cutting edges have the second relief angles at a maximum diameter position. The deflection reducer reduces deflection of the second cutting edges. The deflection reducer is formed between the first cutting edges and the second cutting edges. The deflection reducer is inserted into the prepared hole.

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 step drill bit includes a shank and a body having a proximal end adjacent the shank and a distal end opposite the proximal end. The body defines a plurality of axially stacked, progressively sized steps including a first step at the distal end, a terminal step at the proximal end, and a plurality of intermediate steps having incrementally increasing diameters disposed between the first and terminal steps. The step drill bit also includes a plurality of cutting edges each disposed along one of the plurality of steps. Each edge defines a helix angle and a radial rake angle. The radial rake angle and the helix angle of the cutting edge at the terminal step is greater than the radial rake angle and the helix angle of the cutting edge at the first step.