| 摘要 |
PURPOSE: To unnecessitate a drilling tool of a large diameter and easily and surely provide a right bore hole by making a distance between an outer edge of a bar-shaped parts and a longitudinal center axis of a circumferetial circle of a cylindrical wall hole which is matched with a peripheral surface circle of the drilling tool equal to a length that a radius of a faulty bore hole is added to the eccentricity of the faulty bore hole and the bore hole. CONSTITUTION: This device is provided with a guide element 14 because the cross section of a faulty bore hole 20 and the cross section of a bore hole 22 intersect each other or are directly adjacent. In the guide element 14, a hole having a cylindrical wall body and guiding a drilling tool 42 is provided. From the guide element 14, a bar-shaped parts 16 which can be inserted into the faulty bore hole 20 is projected and can be abutted on an inner wall of the faulty bore hole 20 along an outer edge 18. A distance A between the outer edge 18 of the bar-shaped parts 16 and a longitudinal center axis MB of a circumferential circle of a cylindrical wall hole which is matched with a peripheral surface circle of the drilling tool 42 is made equal to a length that a radius of the faulty bore hole 20 is added to the eccentricity E of the faulty bore hole 20 and the bore hole 22 from the viewpoint of a center MF of the cross section of the faulty bore hole 20. |
