Discontinuities
A variety of small or large disfigurations in a fastener such as pits (slight depressions on the surface), tool marks, voids (small cracks), laps, folds and seams (slightly bunched or folded material at the corners of a fastener), and inclusions (a slight non-metallic impurity in the metal). Minor discontinuities are permissible in both commercial fasteners and those made to various MS and other specs.
