Mechanical drilling aid

Mechanical drilling aid for guiding a drilling tool when drilling a correct bore into an object, in particular into a wall, said correct bore to be drilled being disposed eccentrically to an existing faulty bore, wherein the cross-sections of said faulty bore and said correct bore to be drilled intersect each other or extend immediately adjacent to each other, comprising:

• a guide element provided with an opening therein having a cylindrical wall serving for guiding said drilling tool, said cylindrical wall defining a circle at least as large as the circumferential circle of said drilling tool and having a longitudinal center axis coaxial with the axis of the drilling tool, and
• a rod-shaped part projecting from said guide element, said rod-shaped part being introducible into said faulty bore and abutting against an inner wall of said faulty bore, at least along an outer edge of said rod-shaped part, said rod-shaped part being detachable from said guide element so that it can be left in said object, thereby filling a space between said correct bore and said faulty bore,
• wherein the distance between said outer edge of said rod-shaped part and said longitudinal center axis of said cylindrical wall in said guide element is equal to the sum of the amount of eccentricity between said faulty and said correct bore, and the radius of said faulty bore, wherein said distance is measured across a center point of said cross-section of said faulty bore.