ISO/TC 213/WG 12 - Size

This document defines a number of specification operators for the specification of extended edge transition features between features. An edge transition feature is an integral feature connecting two adjacent integral features. The extended edge transition feature includes portions of the adjacent features. All these specifications apply to any line in a defined direction in the extended edge transition feature. This document also defines the specification modifiers and the drawing indications for such transition specifications. The proportions and dimensions of the graphical symbols to be used are also specified. The specifications defined in this document are suitable for relatively simple edge transition functions, for example ensuring assembly without interference. For more complex functions, geometrical tolerancing offers more precise tools. This document is by intention limited to only edge transition features between two planes and between a cylinder and a plane nominally perpendicular to it. Annex A gives the first approach for an algorithm to identify toleranced features and adjacent reference sections. This algorithm is subject to change as more experience is gathered. This document provides a set of tools to express several transition specifications. It does not present any information on the relationship between a function or a use and a transition specification. NOTE 1 Corners (the transition between three or more features) are not edge transition features and are consequently not covered by this document. NOTE 2 An edge transition feature exists between two single features. A defined edge transition feature has a defined nominal shape and is not sharp (r = 0).

This document illustrates the ambiguity caused by the use of dimensional specifications to control properties other than linear or angular size and the benefit of using geometrical specifications instead. Dimensional tolerancing can be indicated by ± tolerancing or geometrical specifications. The ambiguity caused by using ± tolerances for dimensions other than linear or angular sizes (for individual tolerances and general tolerances according to, e.g. ISO 2768-1 and ISO 8062-3) is explained in Annex A. NOTE 1 The figures, as shown in this document, merely illustrate the text and are not intended to reflect actual usage. The figures are consequently simplified to indicate only the relevant principles. NOTE 2 For indications of dimensional specifications, see the following: — ISO 14405-1 for linear size; — ISO 14405-3 for angular size; — ISO 2538-1 and ISO 2538-2 for wedges; — ISO 3040 for cones. NOTE 3 The rules for geometrical specifications are given in ISO 1101.

This part of ISO 14405 establishes the default specification operator for angular size and defines a number of special specification operators for features of angular size: cone (truncated, i.e. frustum, or not), wedge (truncated or not), two opposite straight lines (intersection of a wedge/truncated wedge and a plane perpendicular to the intersection straight line of the two planes of the wedge/truncated wedge, intersection of a cone/frustum and a plane containing the axis of revolution of the cone/frustum). See Figure 1 and Figure 2. This part of ISO 14405 also defines the specification modifiers and the drawing indications for these angular sizes. This part of ISO 14405 covers the following angular sizes: —   local angular size: —   angular size between two lines; —   portion angular size; —   global angular size: —   direct global angular size: —   least squares angular size; —   minimax angular size; —   rank order angular size/indirect global angular size: —   maximum angular size; —   minimum angular size; —   average angular size; —   range of angular sizes; —   mid-range angular size; —   median angular size; —   standard deviation of angular size. This part of ISO 14405 defines the meaning of tolerances of angular sizes indicated as —   + and/or - limit deviations, e.g. 0°/-0,5°, or —   indicated with upper limit of size (ULS) and/or lower limit of size (LLS), e.g. 35° max. or 15° min., 34°/36°, —   with or without modifiers. This part of ISO 14405 provides a set of tools to express several types of angular size characteristics. It does not give any information on the relationship between a function or a use and an angular size characteristic.

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.

ISO 3040:2016 specifies graphical indication applicable to a cone (right-angle circular cones) to define its dimensioning or to specify its tolerancing. For the purposes of this International Standard, the term "cone" relates to right-angle circular cones only (any intersection by a plane perpendicular to the axis of the nominal cone is a circle). NOTE 1 For simplicity, only truncated cones have been represented in this International Standard. However, this International Standard can be applied to any type of cone within its scope. NOTE 2 This International Standard is not intended to prevent the use of other methods of dimensioning and tolerancing.

ISO 2538-1:2014 specifies terms and definitions for wedges, three series of wedge angles from 120° to 0° 30′ and a series of wedge slopes from 1:10 to 1:500, for general mechanical engineering purposes.

ISO 2538-2:2014 specifies methods for the dimensioning and tolerancing of wedges. For simplicity, only truncated wedges have been represented; however, ISO 2538-2:2014 can be applied to any type of wedge.

ISO 1119:2011 provides calculated values for a series of cones or conical tapers, ranging from 120° to less than 1°, or ratios from 1:0,289 to 1:500, intended for general use in technical engineering. It applies only to plain conical surfaces, and excludes prismatic pieces, taper threads, bevel gears, etc.

ISO 286-1:2010 establishes the ISO code system for tolerances to be used for linear sizes of features of the following types: a) cylinder; b) two parallel opposite surfaces. ISO 286-1:2010 defines the basic concepts and the related terminology for this code system. It provides a standardized selection of tolerance classes for general purposes from amongst the numerous possibilities. Additionally, it defines the basic terminology for fits between two features of size without constraints of orientation and location and explains the principles of “basic hole” and “basic shaft”.

ISO 14405-2:2011 illustrates the use of geometrical tolerancing for dimensions that are not linear sizes to avoid the ambiguity that the use of ± tolerances on these dimensions causes. Both linear and angular dimensions, except size of features of size, are covered. Dimensional tolerancing can be indicated by ± tolerancing or geometrical tolerancing. The ambiguity caused by using ± tolerances for dimensions other than linear sizes is explained in an informative annex.

ISO 14405-1:2010 establishes the default specification operator for linear size and defines a number of special specification operators for linear size for feature of size types “cylinder” and “two parallel opposite planes”. It also defines the specification modifiers and the drawing indications for these linear sizes. It covers the following linear sizes: local size; global size; calculated size; and rank-order size. ISO 14405-1:2010 defines tolerances of linear sizes when there is a + and/or – limit deviation, or when there is an upper limit of size and/or lower limit of size; with an ISO size tolerance code in accordance with ISO 286-1, with or without modifiers. ISO 14405-1:2010 provides a set of tools to express several types of size characteristics. It does not present any information on the relationship between a function or a use and a size characteristic.

ISO 3040:2009 establishes the definition of cones and specifies the graphical symbol to be used for their indication and methods for their dimensioning and tolerancing. For the purposes of ISO 3040:2009, the term “cone” relates to right-angle circular cones only.

ISO/TR 16570:2004 describes the ± limit specification of step dimensions, distances, angular sizes and radii when the function relates to two features only.