lihvketta karakteristik, mis iseloomustab abrasiivosakeste vahelist kaugust; eristatakse abrasiivi tihedat, keskmist ja hõredat paigutust lihvketta struktuuris (vt lihvketas), the spacing of the abrasive particles with respect to each other; grinding wheel structure is measured on a scale that ranges between "open" (widely spaced grains) and "dense" (close-packed grains) (see: grinding wheel)