Core drill apparatus

Claim 1

Apparatus for drilling cores in a workpiece comprising: (A) a drill member having a cylindrical cutter head portion and a shank portion adapted to be inserted into a holder of a machine for rotating the drill member; (B) said hollow cylindrical cutter head portion and said shank portion both being machined from the same single piece of stock so as to form a one-piece unitary body lying along a longitudinal axis; (C) said cylindrical cutter head portion including a relatively thin wall portion having a smooth, continuous lower margin and defining a hollow interior; (D) an abrasive cutting material deposited on said lower margin of said relatively thin wall portion; (E) means defining a shoulder portion in the transition region between said cylindrical cutter head portion and said shank portion; (F) said shank portion having at least a radial fluid passageway and an axial fluid passageway extending from said radial fluid passageway to the hollow interior of said cylindrical cutter portion; (G) a short collar member in the form of a relatively thin disk having a central axial aperture adapted to fit over and surround said shank portion and including lower and upper sealing washers having central apertures substantially equal to the dimension of said shank portion so as to form a substantially fluid-tight seal therewith, the arrangement defining an internal cavity surrounding said shank portion; (H) said disk being counterbored on the bottom and top surfaces thereof to thereby define a central internal ledge; (I) said lower and upper sealing washers being press-fit into respective lower and upper portions of said collar member abutting opposite sides at said internal ledge and being held in place by said shoulder portion and said holder of said machine; and (J) means for supplying a fluid to said internal cavity of said collar member.