The straightness tolerance is the measure of the change of the actual line compared to an ideal straight line. The annotation is given on the drawing, to limit the change of the actual line machining error scope.

Circularity tolerance is the measure of the change of the actual round compared to an ideal round in the considered cross-section.The annotation is given on the drawing, to limit the change of the actual round machining error scope.

  Concentricity tolerance zone controls the median points of a feature of size. Concentricity tolerance is a condition in which the elements of a feature' s surface are common to the centre of a datum feature. A concentricity tolerance specifies a circle tolerance zone whose centre of a circle coincides with a datum centre of a circle. The tolerance zone is equally disposed about the datum centre for concentricity. The concentricity requires that the median points of the controlled feature, regardless of its size, to be within the tolerance zone.

Circular Runout zone is limited in the measuring plane perpendicular to the axis by two concentric circles, the common centre of which lies on the datum axis. Also it is can be defined as two-dimensional geometric tolerance that controls the form, orientation, and location of multiple cross sections of a cylindrica1 part as it rotates. For circular runout, the tolerance zone for each circular element on a surface constructed at right angle to the datum axis. The circular element through a surface point conforms to the circular runout tolerance for a given mating surface if all points of the circular eIement lie down within some circular runout tolerance zone. Circular run out controls the cumulative variation of circularity(roundness) and coaxiality for features constructed around a datum axis and circular elements of a surface constructed an angle not parallel to the datum axis. The tolerance zone is an annular surface of revolution about the center axis of the circle and perpendicular to the feature surface.

Tolerance Grade