| 摘要 |
PROBLEM TO BE SOLVED: To provide a coring machine which consists of a simple constitution and enables efficient and stable working without causing a defective state such as a chip in the edge of a circular hole at finishing grinding. SOLUTION: A supporting board 5 for supporting a work 6 is fixed on a reversal base 8 which is rotated normally and reversely at 180 degrees. A spill port 5a having a hole diameter larger than the outside diameter of the grind stone 2 of a core drill 1 is provided in the central part of the supporting board 5 and the reversal base 8. Grinding of the work is enabled in the normal rotation edge and the reverse rotation edge of the reversal base 8. A pedestal 14, which is vertically moved and supports the work while being ground in the ascending edge, is provided in the underside of the reversal base 8.
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