A drill bit has, along a drill bit axis, a drilling head, a multi-start helix made of two or more helical coils, and an insertion end. The helix has a helix slope and a pitch in a delivery region. In an outlet region of the helix, the outlet region being directed towards the insertion end, the helical coils merge continuously, within a first portion, from an orientation in alignment with the helix slope into an orientation parallel to the drill bit axis. A length of the first portion is at least one quarter of the pitch of the delivery region. The helical coils, in a second portion, are oriented parallel to the drill bit axis.

A drill bit has, along a drill bit axis, a drilling head, a multi-start helix made of two or more helical coils, and an insertion end. The helix has a helix slope and a pitch in a delivery region. In an outlet region of the helix, the outlet region being directed towards the insertion end, the helical coils merge continuously, within a first portion, from an orientation in alignment with the helix slope into an orientation parallel to the drill bit axis. A length of the first portion is at least one quarter of the pitch of the delivery region. The helical coils, in a second portion, are oriented parallel to the drill bit axis.

A method of manufacturing a well tool can include loading a matrix material into a mold, then sintering the matrix material in the mold; and then loading another matrix material into the mold. A well tool can include a longitudinal axis, an erosion resistant layer exposed to one or more erosive factors when the well tool is installed in a well, and a support layer which supports the erosion resistant layer. The erosion resistant and support layers can include respective matrix materials, and the erosion resistant layer can extend greater than approximately 1.27 cm in a direction parallel to the longitudinal axis. Another method of manufacturing a well tool can include forming a rigid layer from a powdered matrix material; and then infiltrating both that matrix material and another matrix material with a hot liquid binder material.

A method of manufacturing a well tool can include loading a matrix material into a mold, then sintering the matrix material in the mold; and then loading another matrix material into the mold. A well tool can include a longitudinal axis, an erosion resistant layer exposed to one or more erosive factors when the well tool is installed in a well, and a support layer which supports the erosion resistant layer. The erosion resistant and support layers can include respective matrix materials, and the erosion resistant layer can extend greater than approximately 1.27 cm in a direction parallel to the longitudinal axis. Another method of manufacturing a well tool can include forming a rigid layer from a powdered matrix material; and then infiltrating both that matrix material and another matrix material with a hot liquid binder material.

A method of forming a casing bit includes positioning a cutting element adjacent an outer surface of a casing bit body. The cutting element has a superhard material and a bonding material that is used to bond the cutting element to a body of the casing bit. The bonding material may be a weldable or brazable metal alloy, and a welding process or a brazing process, respectively, may be used to bond the cutting elements to body of the casing bit. Casing bits fabricated using such methods may exhibit reduced bond strength between the cutting elements and the casing bit body.

A constant rake planar cutting edge fluted drill bit and a method of manufacturing the same. The drill bit includes a planar cutting face formed at the tip end of the bit by a motion of a rotating machining wheel respective to a stationary blank in a first step. Once the cutting face is formed, the blank is rotated and translated in a direction parallel to an elongated axis, during which the rotating machining wheel creates a flute. Upon completion of the first flute, the bit is rotated accordingly and the processes are repeated to create each subsequent planar cutting face and respective flute. The process can also be completed in a slightly modified version of a reverse process, fabricating a flute prior to formation of the planar cutting face of the bit.

A constant rake planar cutting edge fluted drill bit and a method of manufacturing the same. The drill bit includes a planar cutting face formed at the tip end of the bit by a motion of a rotating machining wheel respective to a stationary blank in a first step. Once the cutting face is formed, the blank is rotated and translated in a direction parallel to an elongated axis, during which the rotating machining wheel creates a flute. Upon completion of the first flute, the bit is rotated accordingly and the processes are repeated to create each subsequent planar cutting face and respective flute. The process can also be completed in a slightly modified version of a reverse process, fabricating a flute prior to formation of the planar cutting face of the bit.

A system for simultaneously forming multiple flutes in a carbide rotary cutting tool includes a chuck adapted to grasp a green rod member and selectively rotate the green rod member about, and translate the green rod member along, a first axis. The system further includes a mechanism adapted to simultaneously machine multiple flutes in the green rod member as the green rod member is rotated about, and translated along, the first axis.

A constant rake planar cutting edge fluted drill bit and a method of manufacturing the same. The drill bit includes a planar cutting face formed at the tip end of the bit by a motion of a rotating machining wheel respective to a stationary blank in a first step. Once the cutting face is formed, the blank is rotated and translated in a direction parallel to an elongated axis, during which the rotating machining wheel creates a flute. Upon completion of the first flute, the bit is rotated accordingly and the processes are repeated to create each subsequent planar cutting face and respective flute. The process can also be completed in a slightly modified version of a reverse process, fabricating a flute prior to formation of the planar cutting face of the bit.

A constant rake planar cutting edge fluted drill bit and a method of manufacturing the same. The drill bit includes a planar cutting face formed at the tip end of the bit by a motion of a rotating machining wheel respective to a stationary blank in a first step. Once the cutting face is formed, the blank is rotated and translated in a direction parallel to an elongated axis, during which the rotating machining wheel creates a flute. Upon completion of the first flute, the bit is rotated accordingly and the processes are repeated to create each subsequent planar cutting face and respective flute. The process can also be completed in a slightly modified version of a reverse process, fabricating a flute prior to formation of the planar cutting face of the bit.