TYPE OF 
TOLERANCE

CHARACTERISTIC
AND SYMBOL

DATUM
REFERENCE

IMPLIED
CONDITION

ALLOWABLE
MATERIAL MODIFIERS

TOLERANCE
ZONE SHAPE

KEY POINTS TO REMEMBER

LOCATION

CONCENTRICITY

YES

RFS

NONE


CYLINDRICAL
  1. MUST COMPARE AXIS
  2. USE POSITION, PROFILE OR
    RUNOUT INSTEAD IF POSSIBLE
  3. VERY EXPENSIVE

CONCENTRICITY:
The condition where the median points of all diametrically opposed elements of a feature of revolution are congruent with the axis of a datum feature.

CONCENTRICITY TOLERANCE ZONE:
Defined by a cylindrical tolerance zone whose axis coincides with the datum axis and within which all cross-sectional axes of the feature being controlled must lie.