| 摘要 |
PURPOSE:To make loading hard to occur as well as to aim at improvement in durability, by forming a first stone piece, holding super-hard abrasive grains on a circular peripheral part of a segment metal sheet, and a second stone piece, forming soft abrasive grains into a sheet with a bonding agent, laminatedly in an alternate manner. CONSTITUTION:A sector composite stone piece 40 is made up of laminating a super-hard stone piece 20, sticking super-hard abrasive grains consisting of diamond or cubic boron nitride to a circular peripheral part of a sectoral metal sheet 21, and a soft stone piece 30, mixing soft abrasive grains 31 of silicon carbide, fused alumina or the like with a synthetic resin binder 32 and being heated and molded, alternately. Plural pieces of this sectoral composite stone 40 are clamped to a fixture 50, setting it down to a grinding composite stone 10. Thus, a side of the soft stone piece is vigorouts in autogeneous action on a cutting edge to an impact at time of grinding, whereby it wears earlier and a dent is produced, forming an escaping way for chips, so that loading is hard to occur, and heating value is checkable, while grinding operations become so good as well as durability in the stone is sharply improved.
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