Pilot drill with spring detent

A drilling apparatus comprising:

• a pilot drill comprising:
• a shaft defining a longitudinal axis, the shaft further defining a detent cavity extending from an outer surface of the shaft towards the longitudinal axis and a fastener bore angled with respect to an extension direction of the detent cavity, the shaft comprising a cutting edge positioned proximate to the outer surface, the shaft configured to rotate about the longitudinal axis during use and thereby cut through a wall of a pipe;
• and
• a detent comprising:
• a bar positioned at least partly within the detent cavity, the bar comprising
• a base and an ear and defining
• a leading end and a trailing end distal from the leading end, and
• an opening extending from a first side to a second side proximate to the leading end;
• and
• a fastener extending through the fastener bore of the shaft and the opening of the bar and defining a pivot axis, the bar configured to rotate about the pivot axis from a disengaged position to an engaged position, the ear extending past the outer surface of the shaft with respect to the longitudinal axis when the bar is in the engaged position, the ear defining a barbed shape;
• and
• a biasing element positioned adjacent to the bar and at least partially within the detent cavity of the shaft, the biasing element being a torsion spring;
• and
• a shell cutter secured to and fixed with respect to the pilot drill, the shell cutter defining a leading end, a trailing end, and a wall;
• an inner surface of the wall of the shell cutter being offset from the outer surface of the shaft, the shell cutter configured to rotate together with the pilot drill about the longitudinal axis during use and thereby also cut through the wall of the pipe, the leading end of the shell cutter offset in an axial direction behind a tip of the pilot drill.

A method of using a drilling apparatus, the method comprising:

• rotating the drilling apparatus about a longitudinal axis of a shaft of a pilot drill of the drilling apparatus, the drilling apparatus comprising the pilot drill, the pilot drill comprising the shaft and a detent, the detent comprising a bar positioned at least partly within a detent cavity defined in the shaft, the bar configured to rotate about a pivot axis of the pilot drill from a disengaged position to an engaged position, the bar further defining a base and an ear, the ear extending past an outer surface of the shaft with respect to the longitudinal axis when the bar is in the engaged position, the ear defining a barbed shape beyond the outer surface of the shaft;
• forming a pilot hole in a wall of a pipe with the pilot drill;
• passing the detent of the pilot drill through the wall of the pipe with the detent in the disengaged position;
• pushing the bar away from the longitudinal axis with a biasing element, the biasing element being a torsion spring;
• and
• removing a cut pipe coupon of the pipe from the pipe with the detent in the engaged position by moving the drill apparatus in a direction opposite the cutting direction, a biasing element moving the detent from the disengaged position to the engaged position, the pilot drill defining an overall diameter measuring greater than a diameter of the pilot hole with the detent in the engaged position.

A pilot drill comprising:

• a shaft defining a longitudinal axis, the shaft further defining a detent cavity extending from an outer surface of the shaft towards the longitudinal axis and a fastener bore angled with respect to an extension direction of the detent cavity, the shaft comprising a cutting edge positioned proximate to the outer surface, the shaft configured to rotate about the longitudinal axis during use and thereby cut through a wall of a pipe;
• and
• a detent comprising:
• a bar positioned at least partly within the detent cavity, the bar comprising a base and an ear and defining an opening extending from a first side to a second side proximate to a leading end of the bar, the bar defining a shear line at an intersection of the ear and the base of the bar;
• and
• a fastener extending through the fastener bore of the shaft and the opening of the bar and defining a pivot axis, the bar configured to rotate about the pivot axis from a disengaged position to an engaged position, the ear of the bar extending past the outer surface of the shaft with respect to the longitudinal axis when the bar is in the engaged position.

A pilot drill comprising:

• a shaft defining a longitudinal axis, the shaft further defining a detent cavity extending from an outer surface of the shaft towards the longitudinal axis and a fastener bore angled with respect to an extension direction of the detent cavity, the shaft comprising a cutting edge positioned proximate to the outer surface, the shaft configured to rotate about the longitudinal axis during use and thereby cut through a wall of a pipe;
• and
• a detent comprising:
• a bar positioned at least partly within the detent cavity, the bar comprising a base and an ear and defining a first opening extending from a first side to a second side proximate to a leading end of the bar, the bar defining a trailing end distal from the leading end, the bar defining a second opening extending from the first side to the second side between the first opening and the trailing end, the second opening being a slot having a long dimension measured in a direction perpendicular to the longitudinal axis of the shaft;
• a first fastener extending through the fastener bore of the shaft and the first opening of the bar and defining a pivot axis, the bar configured to rotate about the pivot axis from a disengaged position to an engaged position, the ear of the bar extending past the outer surface of the shaft with respect to the longitudinal axis when the bar is in the engaged position;
• and
• a second fastener extending through the shaft and the second opening of the bar.

A method of using a drilling apparatus, the method comprising:

• rotating the drilling apparatus about a longitudinal axis of a shaft of a pilot drill of the drilling apparatus, the drilling apparatus comprising the pilot drill, the pilot drill comprising the shaft and a detent, the detent comprising a bar positioned at least partly within a detent cavity defined in the shaft, the bar configured to rotate about a pivot axis of the pilot drill from a disengaged position to an engaged position, the bar further defining a base and an ear, the ear extending past an outer surface of the shaft with respect to the longitudinal axis when the bar is in the engaged position, the ear defining a barbed shape beyond the outer surface of the shaft, the bar further defining a shear line at an intersection of the ear and the base of the bar, the shear line defined by a weakened portion in a first side of the bar;
• forming a pilot hole in a wall of a pipe with the pilot drill;
• passing the detent of the pilot drill through the wall of the pipe with the detent in the disengaged position;
• and
• removing a cut pipe coupon of the pipe from the pipe with the detent in the engaged position by moving the drill apparatus in a direction opposite the cutting direction, a biasing element moving the detent from the disengaged position to the engaged position, the pilot drill defining an overall diameter measuring greater than a diameter of the pilot hole with the detent in the engaged position.