The handle (12) has a variable dia. through hole, which accepts a section of the drill in the form of a clamp ring and a sprit level bubble mounted on the handle. At least one external surface of the handle forms a measurement plane. A rotatable carrier unit (42) mounted on the surface opposite the measurement plane surface carries a tube spirit level (44) parallel to the external surface. A measurement groove in the measurement plane is parallel to the lateral edge of the plane. A scale is formed on at least one straight edge of the handle.
