The Projected Tolerance Symbol is in used GD&T to indicate the tolerance zone of a feature is to be assessed beyond the surface extents of the feature.
The Continuous Feature Symbol is used to indicate that a group of disjointed features or surfaces are to be considered as one continuous feature.
The Datum Target Symbol is used to define a specific point, line, or area to be used in order to establish a datum on a drawing.
The Envelope Requirement Symbol is used on ISO drawings to declare that size is to control form with respect to perfect form at MMC.
The Independency Symbol is used on drawings to declare that the requirement for perfect form at MMC or LMC is removed and the form tolerance may be larger than the size tolerance. This symbol only exists in the ASME Y14.5 standards, not the ISO GPS standards.
Position is one of the most useful and most complex of all the symbols in GD&T. The two methods of using Position discussed on this page will be RFS or Regardless of Feature Size and under a material condition (Maximum Material Condition or Least Material Condition). Position is always used with a feature of size.
The circularity symbol is used to describe how close an object should be to a true circle...
Parallelism is a fairly common symbol that describes a parallel orientation of one referenced feature to a datum surface or line...
The Cylindricity symbol is used to describe how close an object conforms to a true cylinder...
Profile of a surface describes a 3-Dimensional tolerance zone around a surface, usually which is an advanced curve or shape...
Runout is how much one given reference feature or features vary with respect to another datum when the part is rotated 360° around the datum axis.
Concentricity, is a tolerance that controls the central derived median points of the referenced feature, to a datum axis. Concentricity is a very complex feature because it relies on measurements from derived median points as opposed to a surface or feature’s axis.
Perpendicularity is a fairly common symbol that requires the referenced surface or line to be perpendicular or 90° from a datum surface or line...
Total Runout is how much one entire feature or surface varies with respect to a datum when the part is rotated 360° around the datum axis...
Profile of a line describes a tolerance zone around any line in any feature, usually of a curved shape...
Angularity is the symbol that describes the specific orientation of one feature to another at a referenced angle...
The standard form of straightness is a 2-Dimensional tolerance that is used to ensure that a part is uniform across a surface or feature. Straightness can apply to either a flat feature such as the surface of a block, or it can apply to the surface of a cylinder along the axial direction. It is defined as the variance of the surface within a specified line on that surface.
