| 摘要 |
PURPOSE:To enable to machine a groove for insulation of the shape having excellent pressure resistant characteristic, namely, the groove having large hole size and small bottom curvature and to eliminate early damage by bonding flat grindstone of thin flat plate shape having a size slightly larger in the outer diameter than a one side angular grindstone on the other side surface of the one side angular grindstone. CONSTITUTION:Since a grindstone 17 is formed of a one side angular grindstone 20 and a flat grindstone 21 having a size slightly larger in the outer diameter than the grindstone 20, the hole size of a groove 22 for insulation can be, in case of machining the groove 22, formed in the large size proportional to the inclining angle and cutting depth of the end of the grindstone 20, and the bottom curvature can be formed in size sufficiently smaller than approx. 1/2 of the thickness of the grindstone 21. According to the grindstone 20, when the notch is formed, horizontal plane force components Fx, Fy are operated, the component Fx largely affects the influence of the lifetime of the grindstone 21, but the flat grindstone 21 which is affected by the horizontal plane force component Fx is supported by the grindstone 20, and the grindstone 21 does not accordingly bend nor break. |
