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.

An orthopedic screw extractor device including a shaft, an end portion about a first end of the shaft for securing to a handle, and a screw extracting tip about a second end of the shaft opposite the first end. The screw extracting tip further includes a generally frustoconical shape having a side at an angle of about 5 to 15 degrees relative to a longitudinal axis of the screw extracting tip. The screw extracting tip further includes first, second and third screw threads and first, second and third flutes circumferentially spaced about the screw extracting tip and extending across an entire length of the screw extracting tip. Each of the screw threads has a lead of about 0.07 to 0.12 inches, a pitch of about 0.02 to 0.04 inches, a thread angle of about 40 to 50 degrees, and a depth of about 0.01 to 0.02 inches.

An orthopedic screw extractor device including a shaft, an end portion about a first end of the shaft for securing to a handle, and a screw extracting tip about a second end of the shaft opposite the first end. The screw extracting tip further includes a generally frustoconical shape having a side at an angle of about 5 to 15 degrees relative to a longitudinal axis of the screw extracting tip. The screw extracting tip further includes first, second and third screw threads and first, second and third flutes circumferentially spaced about the screw extracting tip and extending across an entire length of the screw extracting tip. Each of the screw threads has a lead of about 0.07 to 0.12 inches, a pitch of about 0.02 to 0.04 inches, a thread angle of about 40 to 50 degrees, and a depth of about 0.01 to 0.02 inches.

A drill bit includes a shank, a transition portion, and a body portion defining a plurality of axially stacked, progressively sized steps. The steps include a first step and a terminal step coupled to the transition portion. The first step defines two tip flutes each disposed at a tip flute angle. The body portion defines two body flutes each extending from the first step to the transition portion and disposed at a body flute angle different from the tip flute angle. The drill bit includes a bit tip disposed at the distal end of the body portion and having a chisel edge, a first chisel surface on one side of the chisel edge, and a second chisel surface on an opposite side of the chisel edge. The first chisel surface defines a first relief angle. The second chisel surface defines a second relief angle different from the first relief angle.

A drill bit, e.g., a serpentine drill or an auger bit, includes a circumferential chip removal groove helically about a drill axis and a centering tip having a conical shape with an apex on the drill axis. The centering tip has a lateral cone surface that has a taper angle with a centering tip helical thread which spirals helically from the apex down the centering tip in a thread direction of rotation at a tip thread pitch. At least one tip recess is included in a side of the centering tip which provides a cutting edge, and which has a chip transporting shape and connecting to the circumferential external thread. The cone surface includes at least one step in the taper angle of the lateral surface with each step starting at a step-start position and the at least one step continues about the drill axis at least 90 degrees.

The invention relates to a conical countersink (10) having at least one main cutting edge (16-1, 16-2, 16-3) extending in an arc-shaped, in particular spiral-shaped manner.

A drilling tool has a working piece retained by a retainer mounted to a collar. The working piece includes a distal shank and a cutting section and is rotationally fixed relative to the retainer. The retainer may include an engagement protrusion positioned outward of the shank with the protrusion engaging an inner surface of the collar or the collar may include an engagement protrusion with the protrusion engaging an inner surface of the retainer to create a quasi-floating relationship between the retainer and collar. The cutting section may have a distal primary bore cutting sub-section and a proximal counterbore cutting sub-section. The collar includes a lower surface for abutment against a building member during drilling operation to halt axial movement of the tool.

An accessory tool includes an adapter end, and a shank coupled to the adapter end and including a first length. The shank includes a tool engagement portion, and a first reduced portion disposed between the tool engagement portion and the adapter end. The first reduced portion has a second length. The shank additionally includes a second reduced portion formed in the tool engagement portion between the first reduced portion and an end of the shank. The second length is 2.5% to 15% of a total length of the accessory tool.

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.