GD&T Symmetry Definition

In GD&T, symmetry tolerance establishes a tolerance zone for the median points of non-cylindrical part features.  This tolerance is similar to concentricity, and the verification of symmetry tolerence is likewise time-consuming and difficult.  It is generally recommended that position, parallelism, or straightness be used in lieu of symmetry tolerance.

An example of symmetry tolerance is shown below.  The top figure shows the symmetry symbol applied to a notch.  The boxed symbols can be read "the median points of these opposing surfaces must be symmetric about datum axis A within a tolerance zone of 0.7".  The bottom figure shows and example part that meets this requirement.  The median points must lie between two planes 0.7 apart and equally spaced about datum axis A. 

Symmetry

Was this article helpful? YesSomewhatNo
Get Our FREE CAD Software

Easy to use. Expert feedback. Real-time pricing.

Request a Quote

Send us your file for a quote.

Video Tutorial

Testimonials

Thank you. I hoped that there was this kind of service on the net and there you are. And it wasn`t hard to find you. The term "sheet metal ...

- Julius

View all Testimonials >>