Patent ID: 7377730

Claim:
A drill comprising: a cutting head releasably mounted on a forward end of a tool shank, having a common axis of rotation defining a direction of rotation, the cutting head comprising a cap portion and a fixation portion, the cap portion comprising a head surface, a head base surface and a peripheral side surface extending therebetween, the head base surface being transverse to the axis of rotation, the fixation portion protruding rearwardly from the head base surface away from the head surface and comprising a head fixation surface extending circumferentially relative to the axis of rotation; at least two head flutes extending along a periphery of the cap and fixation portions, and forming identical head segments between adjacent pairs of head flutes, each head segment comprising: a cap recess opening out to the peripheral side surface and the head base surface and dividing the head base surface into first and second head base surfaces no part of the cap recess acting as one of the first or second head base surfaces, a head torque transmission wall extending along a portion of the cap recess transverse to the head base surface and generally facing opposite the direction of rotation, a head fixation recess dividing the head fixation surface into first and second head fixation surfaces; at least two shank flutes extending along a periphery of the tool shank and forming identical shank coupling portions between adjacent pairs of shank flutes, at the forward end of the tool shank, each shank coupling portion comprising: a forwardly facing shank support surface, a shank fixation surface located axially rearwardly relative to the shank support surface, a shank fixation recess dividing the shank fixation surface into first and second shank fixation surfaces; a protuberance protruding forwardly from each shank support surface and dividing the shank support surface into first and second shank support surfaces, and a shank torque transmission wall extending along a portion of the protuberance transverse to the shank support surface and generally facing the direction of rotation; wherein pairs of head segments and shank coupling portions are in mating relationship, and wherein for each such pair the first head base surface abuts the first shank support surface, the second head base surface abuts the second shank support surface, the head torque transmission wall abuts the shank torque transmission wall, the first head fixation surface abuts the first shank fixation surface and the second head fixation surface abuts the second shank fixation surface.