A cutter head arrangement comprising a cutter head portion including a cutter head side wall to define a chamber (or cavity) surrounded by the cutter head side wall. A substantially circular rim portion extends from (a distal end of) the cutter head side wall, the rim portion defining a working, contact face of the cutter head portion. A recessed wall portion extends away from the rim portion inwardly into the chanber so as to be surrounded by the cutter head side wall, with the rim portion and/or the recessed wall portion being fitter with a plurality of cutter elemenets, to enable the cutter head portion to blind bore a pilot hole in use. The recessed wall portion that extends away from the rim portion inwardly into the chamber is a substantially conical body so as to define a conical recess.