Seen in the context of manufacturing machining process, the ability to rough-grind glass, an essentially brittle material, firstly to form, incurring considerable sub- surface damage, and then to free-abrasively polish it to nanometric roughness levels and micrometric form, is remarkable. Single-point studies of the fracture mechanics and machinability of glasses show that, at incursion levels of sub-micrometer order and forces of the order of grams, plastic deformation dominates material deformation processes. The implications of brittleness being scale- dependent ar considerable embracing the possibilities for single-point machining. Whereas it is difficult to experimentally observe the action of a single-particle among the many under a lap, observation and analysis of single- point machining may be usefully employed to explain lap-grit actions. Surface roughness values, damage-depths, interface presentation, limitations on inherent form-convergence and the role of statistical averaging in abrasion may be combined to provide a mechanical model for certain particulate actions.