TYPE OF
TOLERANCE
CHARACTERISTIC
AND SYMBOL
DATUM
REFERENCE
IMPLIED
CONDITION
ALLOWABLE
MATERIAL MODIFIERS
TOLERANCE
ZONE SHAPE
KEY POINTS TO REMEMBER
PLUS / MINUS
ANGLE
YES
RFS
N/A
DEPENDENT
ON

DIMENSION
  1. CONTROLS ORIENTATION OF FEATURE RELATIVE TO A DATUM REFERENCE
  2. DOES NOT PERMIT FUNCTIONAL GAGING TECHNIQUES
  3. DOES NOT ALLOW ADDITIONAL TOLERANCE BASED ON SIZE (BONUS)
  4. RELATIVELY INEXPENSIVE TO VERIFY

PLUS/MINUS ANGLE:
The condition of a surface, center plane, or axis at a specified angle (other than 90 degrees) from a datum plane or axis.

PLUS/MINUS ANGLE TOLERANCE ZONE:
Where an angular surface is defined by a combination of a linear dimension and an angle, the surface must lie within a tolerance zone represented by two non-parallel planes.


The tolerance zone will widen as the distance from the apex of the angle increases. Where, a tolerance zone with parallel boundaries is desired, a basic angle may be specified.