. . . "No. 51,940 7 (Ilaims. (Cl. 512tl9) The present invention relates to rotary grinding wheels of the type commonly employed for grinding materials such as ceramics, glass, carbides, ferrites and the like and has particular reference to that type of grinding wheel which employs a series of appropriately shaped abrasive segments which are positioned in coplanar relationship on the planar or other opera" .