ASME Y14.5-2009 pdf download

ASME Y14.5-2009 pdf download.Dimensioning and Tolerancing.
5.4.2 Flatness Flatness is the condition of a surface or derived median plane having all elements in one plane. A flat- ness tolerance specifies a tolerance zone defined by two parallel planes within which the surface or derived median plane must lie. When a flatness tolerance is spec- ified on a surface, the feature control frame is attached to a leader directed to the surface or to an extension line of the surface. It is placed in a view where the sur- face elements to be controlled are represented by a line. See Fig. 5-7. With flatness of a surface, where the con- sidered surface is associated with a size dimension, the flatness tolerance must be less than the size tolerance. When the independency symbol is applied to the size dimension, the requirement for perfect form at MMC is removed and the form tolerance may be larger than the size tolerance. 5.4.2.1 Application of Flatness RFS, MMC, or LMC to Noncylindrical Features. As an extension of the princi- ples of para. 5.4.1.2, flatness may be applied on an RFS, MMC, or LMC basis to noncylindrical features of size. In this instance, the derived median plane must lie in a tolerance zone between two parallel planes separated by the amount of the tolerance.
6.4.1 Orientation Tolerance Zone An orientation tolerance specifies a zone within which the considered feature, its line elements, its axis, or its center plane must be contained. 6.4.2 Orientation Tolerance An orientation tolerance specifies one of the following: (a) a tolerance zone defined by two parallel planes at the specified basic angle from, parallel to, or perpen- dicular to one or more datum planes or a datum axis, within which the surface or center plane of the consid- ered feature must lie. See Figs. 6-1 through 6-5. (b) a tolerance zone defined by two parallel planes at the specified basic angle from, parallel to, or perpen- dicular to one or more datum planes or a datum axis, within which the axis of the considered feature must lie. See Figs. 6-6 and 6-7. (c) a cylindrical tolerance zone at the specified basic angle from, parallel to, or perpendicular to one or more datum planes or a datum axis, within which the axis of the considered feature must lie. See Figs. 6-8 through 6-15. (d) a tolerance zone defined by two parallel lines at the specified basic angle from, parallel to, or perpen- dicular to a datum plane or axis, within which the line element of the surface must lie. See Figs. 6-16 and 6-17.
6.4.5 Explanation of Orientation Tolerance at MMC An orientation tolerance applied at MMC may be explained in terms of the surface or the feature axis. In certain cases of extreme form deviation (within limits of size) of the hole, the tolerance in terms of the feature axis may not be exactly equivalent to the tolerance in terms of the surface. In such cases, the surface interpretation shall take precedence as in Fig. 7-6. (a) In Terms of the Surface of a Hole. While maintaining the specified size limits of the hole, no element of the hole surface shall be inside a theoretical boundary (vir- tual condition) oriented to the datum reference frame. See Fig. 7-6.