Calibration head for the drilling of shafts

A cylindrical calibration head for drilling a shaft comprising:

• three flutes extending along an axis of said cylindrical calibration head and uniformly distributed around a circumference of the cylindrical calibration head so that the three flutes are separated from each other by an angle of 120° in rotation about the axis of the cylindrical calibration head, the flutes being arranged for evacuation of chips and passage of a lubrication during drilling, each of the flutes comprising a machining insert, a position of which is adjusted in the flute by an adjustment cartridge;
• at least one front guide pad arranged on an outside surface of the cylindrical calibration head in a first zone corresponding to a front end of the head, and
• a plurality of back guide pads arranged on the outside surface of said cylindrical calibration head in a second zone defining a back zone of the cylindrical calibration head, two back guide pads being arranged symmetrically relative to each other about the axis of the cylindrical calibration head and of which at least one back pad is axially offset from a front pad,
• wherein at least one of the back guide pads is aligned with the at least one front guide pad, along a same axis as the at least one front guide pad.

A cylindrical calibration head for drilling a shaft comprising:

• three flutes extending along an axis of said cylindrical calibration head and uniformly distributed around a circumference of the cylindrical calibration head so that the three flutes are separated from each other by an angle of 120° in rotation about the axis of the cylindrical calibration head, the flutes being arranged for evacuation of chips and passage of a lubrication during drilling, each of the flutes comprising a machining insert, a position of which is adjusted in the flute by an adjustment cartridge;
• at least one front guide pad arranged on an outside surface of the cylindrical calibration head in a first zone corresponding to a front end of the head, and
• at least one back guide pad placed on the outside surface of said cylindrical calibration head in a second zone defining a back zone of said cylindrical calibration head, the at least one back guide pad being aligned with the at least one front guide pad, along a same axis as the at least one front guide pad,
• wherein each machining insert has three edges that are configured so as to select a working edge by the adjustment cartridge.

A cylindrical calibration head for drilling a shaft comprising:

• three flutes extending along an axis of said cylindrical calibration head and uniformly distributed around a circumference of the cylindrical calibration head so that the three flutes are separated from each other by an angle of 120° in rotation about the axis of the cylindrical calibration head, the flutes being arranged for evacuation of chips and passage of a lubrication during drilling, each of the flutes comprising a machining insert, a position of which is adjusted in the flute by an adjustment cartridge;
• at least one front guide pad arranged on an outside surface of the cylindrical calibration head in a first zone corresponding to a front end of the head, said first zone covering half of a length of the cylindrical calibration head, the at least one front guide pad arranged exclusively in said first zone, and
• at least one back guide pad placed on the outside surface of said cylindrical calibration head in a second zone defining a back zone of said cylindrical calibration head, said second zone covering a remaining half of the length of the cylindrical calibration head, the at least one back guide pad arranged exclusively in said second zone,
• the at least one back guide pad being placed behind and in alignment with the at least one front guide pad, along a same axis as the at least one front guide pad,
• wherein each of the three flutes extends from a first end of the cylindrical calibration head toward a second end of the cylindrical calibration head along said axis of the cylindrical calibration head and wherein the machining insert of each of the three flutes is positioned, along said axis, closer to said first end of the cylindrical calibration head than the at least one front guide pad.

A cylindrical calibration head for drilling a shaft comprising:

• three flutes extending along an axis of said cylindrical calibration head and uniformly distributed around a circumference of the cylindrical calibration head so that the three flutes are separated from each other by an angle of 120° in rotation about the axis of the cylindrical calibration head, the flutes being arranged for evacuation of chips and passage of a lubrication during drilling, each of the flutes comprising a machining insert, a position of which is adjusted in the flute by an adjustment cartridge;
• at least one front guide pad arranged on an outside surface of the cylindrical calibration head in a first zone corresponding to a front end of the head, said first zone covering half of a length of the cylindrical calibration head, the at least one front guide pad arranged exclusively in said first zone, and
• a plurality of back guide pads arranged on the outside surface of said cylindrical calibration head in a second zone defining a back zone of the cylindrical calibration head, two back guide pads being arranged symmetrically relative to each other about the axis of the cylindrical calibration head and of which at least one back pad is axially offset from a front pad,
• wherein the second zone covers a remaining half of the length of the cylindrical calibration head,
• wherein at least one of the back guide pads is arranged exclusively in said second zone, and
• wherein the at least one of the back guide pads is placed behind and in alignment with the at least one front guide pad, along a same axis as the at least one front guide pad.