TYPE OF 
TOLERANCE

CHARACTERISTIC
AND SYMBOL

DATUM
REFERENCE

IMPLIED
CONDITION

ALLOWABLE
MATERIAL MODIFIERS

TOLERANCE
ZONE SHAPE

KEY POINTS TO REMEMBER

FORM

STRAIGHTNESS

NONE

RFS

MMC OR LMC
ON THE TOLERANCE
IF THE TOLERANCE
APPLIES TO A
FEATURE OF SIZE


TOTAL WIDTH

CYLINDRICAL
  1. COMPARES TO A PERFECT
    COUNTERPART OF ITSELF
    (STRAIGHT LINE)
  2. ADDITIVE TO SIZE WHEN
    APPLIED TO AN AXIS

STRAIGHTNESS:
A condition where an element of a surface or an axis is a straight line

STRAIGHTNESS TOLERANCE ZONE:
A tolerance zone within which the considered element or derived median line, must lie.