
Tolerance & GD&T
True Position for Bolt-Hole and Dowel Patterns: A CNC Buyer’s Decision Guide
Position tolerance—often called “true position” in everyday manufacturing—controls where a feature of size may be located relative to theoretically exact dimensions and a datum reference frame. For bolt-hole and dowel patterns, it can express assembly function more accurately than separate plus/minus X and Y tolerances. It can also be misapplied.