234 Machine Drawing
dharm
d:\N-Design\Des15-2.pm5
15.5.7 Indicating Geometrical Tolerances on the Drawing
To eliminate the need for descriptive notes, geometrical tolerances are indicated on drawings
by symbols, tolerances and datums, all contained in compartments of a rectangular frame, as
shown in Fig. 15.17.
15.5.8 Indication of Feature Controlled
The feature controlled by geometrical tolerance is indicated by an arrowhead at the end of a
leader line, from the tolerance frame.
Table 15.7 Symbols representing the characteristics to be toleranced
Characteristics to be toleranced Symbols
Straightness
Flatness
Form of single features Circularity (roundness)
Cylindricity
Profile of any line
Profile of any surface
Parallelism
Orientation of related features Perpendicularity (squareness)
Angularity
Position
Position of related features Concentricity and coaxiality
Symmetry
Run-out