This paper presents the mirror grinding of high chromium roll steels using a metal bonded coarse grain cBN wheel prepared by the micro dressing. Many grain cutting edges having a flat surface consisted of ductile smooth surfaces as well as a lot of micro brittle dents are formed on the working surface of the coarse grain cBN wheel with a mesh size #140 by the micro dressing using a fine grain diamond dresser. A series of surface grinding experiments with these wheel working surfaces are

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... d to confirm the possibility of creating the mirror surface. The mirror surface with a roughness less than 0.2 μm Rz can be efficiently formed using a working surface prepared by this micro dressing method. This prepared wheel surface can be kept creating the mirror surface with a roughness less than 0.2 μm Rz for nine hours or more. The flat plane due to attritious wear of the cutting edge extends gradually with an increase of the accumulated stock removal, and at the same time, the evenness on the wear flat plane increases gradually with increasing its area. This increasing in the evenness of the wear flat plane is a main factor for increasing the roughness of the mirror surface.