Is Circularity and Roundness the Same?

Sometimes called roundness, circularity is a 2-Dimensional tolerance that controls the overall form of a circle ensuring it is not too oblong, square, or out of round. Roundness is independent of any datum feature and only is always less than the diameter dimensional tolerance of the part.

What is the difference between roundness and Cylindricity?

Roundness callouts on drawings have no reference to a datum, as roundness does not relate to the cross-section's location on the part. Cylindricity is the 3D version of roundness. It assesses how closely an object comes to a perfect cylinder, meaning that it is not only round, but also straight along its axis.

What is the difference between circularity and runout?

Circularity is a 2D callout that controls only form. It cannot be referenced to a datum axis. ... The Circular Runout callout (commonly referred to as runout) controls location, orientation, and (usually) form in two dimensions. One exception is when the size tolerance is more strict than the runout tolerance.