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LATENT MILLING MARKS ON GLASS *
Author(s) -
Jones F. Shirley
Publication year - 1946
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1946.tb11561.x
Subject(s) - diamond , grinding , materials science , composite material , diamond grinding , etching (microfabrication) , isotropic etching , mineralogy , polishing , optics , geology , grinding wheel , physics , layer (electronics)
A bstract It is possible for ground or polished glass surfaces, which were originally milled to the desired shape with a diamond‐charged wheel and which are apparently flawless to microscopic examination in plain or polarized light, to reexhibit the milling pattern on being etched in acid. The depth of glass that must be removed to banish the effect varies with the size of the grit used in the tool. Thin polished slabs (under pressure) break at times along a milling mark whose presence is verified later by etching. The effect can be interpreted as due to tiny vertical fractures similar to those described by Preston in cutting glass with a glazier's diamond. The sides of the fracture must be in optical contact to escape detection by visual means. Another interpretation might be that a certain amount of surface flow exists during grinding. The glass in the milling marks differs in either case from the body of glass in its chemical and physical properties.