How straight is straight enough? How flat is flat enough? Aluminum extrusions , and extrusion-based components, can be produced to very precise tolerances, as well as to accepted "industry standard" dimensional tolerances. More complex components may call for geometric dimensioning and tolerancing, in order to specify the shape-related intricacies of the design.

Tolerance Tables

Additional information regarding tolerances can be found in AEC's Aluminum Extrusion Manual. Tolerance tables, setting forth both industry standard and "precision" tolerances, are available in Aluminum Standards & Data published by The Aluminum Association. Note that many extruders can — if required — achieve tighter tolerances than indicated in the tables. Thus, tolerance requirements for a particular component is often an important discussion topic between designer and extruder.

The following excerpt from the 2009 Aluminum Standards & Data — depicting standard tolerances — is presented with permission of The Aluminum Association.