ISO 14405-3:2016 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.
ISO 14405-3:2016 also defines the specification modifiers and the drawing indications for these angular sizes.
ISO 14405-3:2016 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.
ISO 14405-3:2016 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.
ISO 14405-3:2016 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.