2004

532 | Chapter 20 Dimensions and Tolerances
Display Lateral Tolerances
A lateral tolerance specifies the amount by which a dimension can vary. By
specifying tolerances in manufacturing, you can control the degree of accu-
racy needed for a feature. A feature is some aspect of a part, such as a point,
line, axis, or surface.
You can apply tolerances directly to a dimension by appending the toler-
ances to the dimension text. These dimension tolerances indicate the largest
and smallest permissible size of the dimension. You can also apply geometric
tolerances, which indicate deviations of form, profile, orientation, location,
and runout.
Lateral tolerances can be specified from theoretically exact measurements.
These are called basic dimensions and have a box drawn around them.
If the dimension value can vary in both directions, the plus and minus values
you supply are appended to the dimension value as deviation tolerances. If
the deviation tolerance values are equal, AutoCAD displays them with a ±
sign and they are known as symmetrical. Otherwise, the plus value goes
above the minus value.
If the tolerances are applied as limits, AutoCAD uses the plus and minus
values you supply to calculate a maximum and minimum value. These values
replace the dimension value. If you specify limits, the upper limit goes above
the lower.
symmetrical deviation tolerancedeviation tolerance