PARALLELISM

Parallelism is the relationship of surfaces in different planes. To be parallel the planes passing through the surfaces must be equidistant from each other at all points when measured at 90° to the planes.

Rubber Product with metal Inserts

Example:
In Sketch 1 Fig 9 the plates of the sandwich mount are parallel. In Sketch 2 Fig 9 they are not. On such a part approximately 200mm (8in) square, parallelism to within 0.75mm (.030in) can be expected.