Disclosed is a drilling device and a method for the drilling of human or animal bone tissue. The method comprises the following steps (a) providing a drill having an electrically conductive bone cutter and an electrically conducting nosepiece assembly spaced apart from the electrically conductive bone cutter and acting as a counter electrode (b) placing the electrically conductive bone cutter and nosepiece assembly into contact with the bone tissue to be drilled (c) measuring the electrical impedance between the bone cutter tip and the nosepiece or the current through the cutter motor (d) commencing drilling and moving the bone cutter toward the bone surface (e) starting a step counter when the impedance reduces or the cutter motor current increases (f) incrementing the step counter with every step of the vertical drive motor until the step count reaches the prespecified value thereby controlling the depth of the hole drilled.
