A method employing an apparatus in conjunction with a hammer-drill to penetrate composite metal and non-metal structure or structures including, for example, thick metal or rebar encountered during concrete, rock or masonry boring operations without requiring a change in drill equipment.

A drill bit includes a shank and a body portion defining a plurality of axially stacked, progressively sized steps. The steps include a first step and a terminal step. The first step defines two tip flutes each disposed at a tip flute angle. The body portion defines a body flute extending through the steps. The drill bit also includes an indicator band formed on a portion of the body flute and a portion of an outer surface of one of the plurality of steps.

A vertical-edge double-step sawtooth cutter for preparing high-quality holes of composite material and thereof hybrid stack structure, and has three parts which are a major cutting edge region A, a minor cutting edge region B and a shank region C. The minor cutting edge region B comprises a step vertical-edge region D and a sawtooth cutting region E. This has the step structure and the sawtooth structure which is distributed in the first step, has a recutting function at the inlet and a reverse cutting function at the outlet in the direction opposite to the main cutting motion. The cutter has the vertical edge structure distributed in the second step, and the angle of the second step is a negative value, thereby realizing chip breaking and crushing, reducing scratch to the upper-layer composite material and metal hole walls.

A method employing an apparatus in conjunction with a hammer-drill to penetrate composite metal and non-metal structure or structures including, for example, thick metal or rebar encountered during concrete, rock or masonry boring operations without requiring a change in drill equipment.

A rotary tool according to a non-limiting aspect includes a body having a rotation axis and extending from a first end to a second end. The body including: a first part including the first end; a second part located closer to a second end than the first part and having a larger outside diameter than the first part; a cutting edge located at a side of the first end; a ridge portion located in the first part and the second part, connected to the cutting edge and helically extending from the cutting edge toward the second end; and a flute located along the ridge portion. The flute includes: a first flute located at the first part and having a first helix angle; and a second flute located at the second part and having a second helix angle. The second helix angle is smaller than the first helix angle.

The present invention provides a twist drill. A cone portion is provided at a front end of the operating portion, and an exterior surface of the operating portion is provided with a spiral flute for shunting cutting chips. The exterior surface of the cone portion is provided with a plurality of composite cutting blade groups which are sequentially enlarged in diameter from the front end to the rear end of the cone portion. The cone portion is provided with a top blade on the tip. In use, the top blade is used for positioning, and the cutting process is carried out by the top blade and the composite cutting blade groups.

A deep hole drilling system and methods provide stability and cutting performance to produce deep holes having desired straightness. The system may include a replaceable cutting head provided with a center cutting member and first and second side cutting inserts. The tool provides a major diameter with the OD cutting margins on the replaceable side inserts, as well as possibly cutting margins on the center cutting member. Adjustment mechanisms are provided to adjust the center cutting member and/side cutting inserts.

A cutting tool body includes a first member and a second member, both having a substantially cylindrical shape, and arranged such that a tool body central axis coincides with a central axis of each of the first and the second members. The first member has a tool characteristic of a first magnitude and the second member has the tool characteristic of a second magnitude, different from the first magnitude. The cutting tool body includes a transition member arranged between the first and second members and connected at a first end to the first member and at a second end to the second member. The tool characteristic in the transition member is of the first magnitude at the first end and of the second magnitude at the second end. The transition member has a transition region between the first and the second ends in which the tool characteristic transforms from the first magnitude to the second magnitude.

A twist drill with a multi-step drill point includes a shank and a cutting portion. The cutting portion is provided with a spiral flute and a body clearance. A tip of the cutting portion is provided with a chisel edge and a cutting edge. A flank face connected with the cutting edge is provided with a stepped groove which divides the cutting edge into several sections. A pitch of the stepped groove gradually decreases along a direction from the tip of the cutting portion to the shank.

The present invention relates to a step drill bit, characterized in that the step drill bit has a hole processing portion and at least two flutes extending on the hole processing portion, the hole processing portion comprising step sections, each step section and the at least two flutes forming at least two cutting edges distributed in a circumferential direction of the step section, wherein, the at least two cutting edges on at least one of the step sections at least comprise a first cutting edge and a second cutting edge, wherein the first cutting edge and the second cutting edge are respectively constructed in at least two-segment style, and therefore respectively include at least two cutting edge segments, wherein the first cutting edge and the second cutting edge are at least partially different from each other in the structure of their cutting edge segments, or one cutting edge of the first cutting edge and the second cutting edge is formed in one-segment style, while the other cutting edge is formed in at least two-segment style, and thus includes at least two cutting edge segments. The present invention further relates to a method for drilling a workpiece by using a step drill bit.