A guiding tool for the drill bit of a drilling apparatus and a method of making drills. The tool includes a body with an orifice for passage of the drill bit and a base with at least three protruding feet for resting on the working surface. The feet are configured with inner holes with an outlet at its ends. The tool is connected to a pneumatic device of pressurized gas supply which includes a signal indicative of correct positioning of the tool for performing a drill when a simultaneous blocking of gas output in said feet is produced when all of them are in contact with said working surface; the tool including a pressurized gas pipeline up to said feet.