Abstract: Rotary drill apparatus is disclosed herein which is secured to a turning shaft by an adapter plate. A cylindrical core drill body downwardly depends from the plate to terminate in a plurality of cutting teeth capable of cutting an annular groove to define a core intended to be pulverized. An internal drill bit is carried on the plate in coaxial spaced relationship with respect to the circular arrangement of teeth for forcibly engaging the defined core so as to grind and powderize the core within the core drill body. A circulating coolant system carries the ground and powderized core away from the drill leaving no core chunks or residue.