Trepanning tool with plug management

A trepanning apparatus, comprising:

• a) a shaft portion extending along a longitudinal axis;
• b) an annular cutter portion spaced axially forward of, and coaxial with, the shaft portion, the cutter portion having a forward end for supporting a cutting surface and a rearward end axially rearward of the forward end, and the cutter portion having a generally cylindrical radially outer surface and a radially inner surface opposite the radially outer surface;
• and
• c) a connecting portion extending axially between the shaft portion and the cutter portion, the connecting portion including a pair of arms each having a front end connected to the cutter portion and a rear end connected to the shaft portion, the arms circumferentially spaced from one another about the longitudinal axis to provide diametrically opposed first and second openings on opposed sides of the longitudinal axis, and
• wherein a first plug retaining surface is defined by a first portion of the rearward end of the cutter portion having a first circumferential extent bounded by the front ends of the arms and aligned with the first opening, and wherein a second plug retaining surface is defined by a second portion of the rearward end of the cutter portion having a second circumferential extent bounded by the front ends of the arms and aligned with the second opening, the first circumferential extent greater than the second circumferential extent, and
• wherein the shaft portion has a generally cylindrical outer shaft surface, with a first planar tapered surface centered about the first opening and inclined laterally from the outer shaft surface towards the rear ends of the arms in a forward direction along the longitudinal axis.

A trepanning apparatus, comprising:

• a) a shaft portion extending along a longitudinal axis;
• b) an annular cutter portion spaced axially forward of, and coaxial with, the shaft portion, the cutter portion having a forward end for supporting a cutting surface and a rearward end axially rearward of the forward end, and the cutter portion having a generally cylindrical radially outer surface and a radially inner surface opposite the radially outer surface;
• and
• c) a connecting portion extending axially between the shaft portion and the cutter portion, the connecting portion including a pair of arms each having a front end connected to the cutter portion and a rear end connected to the shaft portion, the arms circumferentially spaced from one another about the longitudinal axis to provide diametrically opposed first and second openings on opposed sides of the longitudinal axis, and
• wherein a first plug retaining surface is defined by a first portion of the rearward end of the cutter portion having a first circumferential extent bounded by the front ends of the arms and aligned with the first opening, and wherein a second plug retaining surface is defined by a second portion of the rearward end of the cutter portion having a second circumferential extent bounded by the front ends of the arms and aligned with the second opening, the first circumferential extent greater than the second circumferential extent, and
• wherein the radially inner surface of the cutter portion is tapered radially inward in a rearward direction along the axis, the spacing between the radially inner and outer surfaces defining a wall thickness of the cutter portion, the wall thickness greater at the rearward end than at the forward end.