ISO 14405-1:2025

ISO 14405-1:2016 establishes the default specification operator (see ISO 17450?2) for linear size and defines a number of special specification operators for linear size for features of size, e.g. "cylinder", "sphere", "torus,"[1], "circle", "two parallel opposite planes", or "two parallel opposite straight lines". It also defines the specification modifiers and the drawing indications for these linear sizes. It covers the following linear sizes: a) local size: - two-point size; - spherical size; - section size; - portion size; b) global size: - direct global linear size: - least-squares size; - maximum inscribed size; - minimum circumscribed size; - minimax size; - indirect global linear size; c) calculated size: - circumference diameter; - area diameter; - volume diameter; d) rank-order size: - maximum size; - minimum size; - average size; - median size; - mid-range size; - range of sizes; - standard deviation of sizes. ISO 14405-1:2016 defines tolerances of linear sizes for the following: - a + and/or ? limit deviation (e.g. 0/?0,019); - an upper limit of size (ULS) and/or lower limit of size (LLS) (e.g. 15,2 max., 12 min., or 30,2/30,181); - an ISO tolerance class code in accordance with ISO 286?1 (e.g. 10 h6); with or without modifiers. ISO 14405-1:2016 provides a set of tools to express several types of size characteristic. It does not present any information on the relationship between a function or a use and a size characteristic. [1] A torus is a feature of size when its directrix diameter is fixed.