A drill bit for a drill includes a body clearance extending helically along the drill bit, a margin also extending helically along the drill bit, adjacent to and projecting radially beyond the body clearance, and a flank at which the body clearance and the margin terminate at a tip of the drill bit. The margin has a variable width along its helical extension.

A drill bit for a drill includes a body clearance extending helically along the drill bit, a margin also extending helically along the drill bit, adjacent to and projecting radially beyond the body clearance, and a flank at which the body clearance and the margin terminate at a tip of the drill bit. The margin has a variable width along its helical extension.

A drilling device includes a drill basic body and a conveying helix which runs helically around the drill basic body. The conveying helix is subdivided into a plurality of conveying helix segments that are disposed next to one another. The conveying helix segments may be disposed loosely next to one another.

A drill may include a body extending from a first end toward a second end, and the body may include an outer peripheral surface and a cutting edge. The cutting edge may include a first cutting edge and a second cutting edge. The second cutting edge may be positioned closer to the second end and the outer peripheral surface than the first cutting edge. The second cutting edge may include a first part, a second part and a third part. The second part may be positioned closer to the outer peripheral surface than the first part and may be positioned closer to the second end as close to the first part. The third part may be positioned closer to the first cutting edge than the first part and may be positioned closer to the second end as close to the first part.

A drill may include a body extending from a first end toward a second end, and the body may include an outer peripheral surface and a cutting edge. The cutting edge may include a first cutting edge and a second cutting edge. The second cutting edge may be positioned closer to the second end and the outer peripheral surface than the first cutting edge. The second cutting edge may include a first part, a second part and a third part. The second part may be positioned closer to the outer peripheral surface than the first part and may be positioned closer to the second end as close to the first part. The third part may be positioned closer to the first cutting edge than the first part and may be positioned closer to the second end as close to the first part.

A spiral step twist drill bit, including 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 is connected to the cutting edge, and is provided with a spiral cutting groove. A spiral direction of the spiral cutting groove is the same as that of the spiral flute. A slope of the spiral cutting groove is the same as that of the flank face. The spiral cutting groove is configured to divide the cutting edge into multiple segments to form multiple first edges and second edges.

A spiral step twist drill bit, including 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 is connected to the cutting edge, and is provided with a spiral cutting groove. A spiral direction of the spiral cutting groove is the same as that of the spiral flute. A slope of the spiral cutting groove is the same as that of the flank face. The spiral cutting groove is configured to divide the cutting edge into multiple segments to form multiple first edges and second edges.

A remanufacturing method of a drill includes providing a drill with a worn-out area. The drill comprises: a shank part; and a flute part arranged on one end of the shank part. A chisel edge is formed on the front end of the flute part, and the radius of any one of the cross section of the chisel edge is defined as a core thickness; a first blade and a second blade with tilt directions toward the shank part are formed on the two sides of the chisel edge. The first circumferential surface of the first blade and the second circumferential surface of the second blade are respectively extended and spiraled toward the shank part along a periphery of the flute part and form two helical cutting edges, a first debris-discharging groove and a second debris-discharging groove. The first blade comprises a first cutting edge. The first cutting edge and the first circumferential surface define the worn-out area. The method also includes a step of aligning a grinding wheel to the worn-out area; and a step of using the aligned grinding wheel to perform a cutting operation along the helical cutting edge or the first debris-discharging groove to grind and repair the worn-out area of the drill.

A remanufacturing method of a drill includes providing a drill with a worn-out area. The drill comprises: a shank part; and a flute part arranged on one end of the shank part. A chisel edge is formed on the front end of the flute part, and the radius of any one of the cross section of the chisel edge is defined as a core thickness; a first blade and a second blade with tilt directions toward the shank part are formed on the two sides of the chisel edge. The first circumferential surface of the first blade and the second circumferential surface of the second blade are respectively extended and spiraled toward the shank part along a periphery of the flute part and form two helical cutting edges, a first debris-discharging groove and a second debris-discharging groove. The first blade comprises a first cutting edge. The first cutting edge and the first circumferential surface define the worn-out area. The method also includes a step of aligning a grinding wheel to the worn-out area; and a step of using the aligned grinding wheel to perform a cutting operation along the helical cutting edge or the first debris-discharging groove to grind and repair the worn-out area of the drill.

Orthopedic systems and methods for installing an implant and/or boring a bone bicortically. The system may include a drill having a proximal boring portion configured to bore a larger hole in a bone more efficiently when the drill rotates in a first direction compared to an opposite second direction, and a distal boring portion configured to bore a smaller hole in the bone more efficiently when the drill rotates in the second direction. The implant may be configured to be implanted at least partially in the bone, such that a first region of the implant is located in the larger hole and a second region of the implant is located in the smaller hole. In an exemplary method, the larger hole and the smaller hole may be bored in the bone's near cortex and far cortex, respectively, by a shaft and a nose of the drill rotated in opposite directions.