Method for grinding or polishing curved surfaces of solid bodies and apparatus for carrying out this method

Apparatus for removing a step-like ridge from, and for simultaneously grinding, an extended portion of the surface of a substantially rotationally symmetric stem of a glass or ceramic article, which surface is curved both laterally and longitudinally, comprising:

• (a) means for rotating the article about the axis of symmetry of said stem, said means including means for securely holding the article as it is rotated;
• (b) at least one rigid tool having a rigid, extended work surface curved to complement said lateral and longitudinal curvature of a sector of said extended portion of the surface of said stem for removing the step-like ridge from, and for simultaneously grinding, said extended portion, the boundary of said work surface defining a sector delimited by:
• (i) the arc of a first circle intercepted by two radii thereof, (ii) the arc of a second, concentrically situated circle intercepted by said two radii, and (iii) said two radii, the angle subtended by said two radii comprising at least about 100.degree.;
• and
• (c) means operatively connected to said tool for pressing said tool work surface against said extended portion of the surface of said stem, said means for pressing being positioned in a plane extending radially with respect to the axis of rotation of the stem to provide a resultant force in said radial plane sufficient to accomplish the desired ridge removal and grinding when the article is rotated, said means for pressing including elastically displaceable support means for displacing the tool during ridge removal and grinding in response to any asymmetry of said surface.