2012

Table Of Contents
Quick Reference
Commands
LEADER
Creates a line that connects annotation to a feature.
TOLERANCE
Creates geometric tolerances contained in a feature control frame.
Datum Reference Frames
The tolerance values in the feature control frame are followed by up to three
optional datum reference letters and their modifying symbols.
A datum is a theoretically exact point, axis, or plane from which you make
measurements and verify dimensions. Usually, two or three mutually
perpendicular planes perform this task best. These are jointly called the datum
reference frame.
The following illustration shows a datum reference frame verifying the
dimensions of the part.
Quick Reference
Commands
LEADER
Creates a line that connects annotation to a feature.
1624 | Chapter 31 Dimensions and Tolerances