GEOMETRIC TOLERANCES

The charts below give the Symbols for Geometric Tolerancing and Additional Symbols,

GEOMETRIC TOLERANCES

Geometric dimensioning and tolerancing (GD&T)is a system for defining and communicating engineering tolerances.

It uses a symbolic language on engineering drawings and computer-generated three-dimensional solid models that explicitly describes nominal geometry and its allowable variation.

It tells the manufacturing staff and machines what degree of accuracy and precision is needed on each controlled feature of the part.

GD&T is used to define the nominal (theoretically perfect) geometry of parts and assemblies, to define the allowable variation in form and possible size of individual features, and to define the allowable variation between features.

Geometric dimensioning and tolerancing provides a comprehensive system for symbolically defining the geometrical tolerance zone.

GEOMETRIC TOLERANCE REFERENCE CHART - ASME Y14.5M And ISO/TC 213
TOLERANCE CHARACTERISTIC SYMBOL DATUM NEEDED APPLICABLE MODIFIERS (RMS, LMC, MMC)
FORM STRAIGHTNESS Straightness NO LMC or MMC CAN APPLY TO FEATURE OF SIZE
FORM FLATNESS Flatness NO DOES NOT APPLY
FORM CIRCULARITY Circularity NO DOES NOT APPLY
FORM CYLINDRICITY Cylindricity NO DOES NOT APPLY
PROFILE LINE PROFILE Line Profile NO DOES NOT APPLY
PROFILE SURFACE PROFILE Surface Profile NO DOES NOT APPLY
ORIENTATION PERPENDICULARITY Perpendicularity YES LMC or MMC CAN APPLY TO FEATURE OF SIZE
ORIENTATION ANGULARITY Angularity YES LMC or MMC CAN APPLY TO FEATURE OF SIZE
ORIENTATION PARALLELISM Parallelism YES LMC or MMC CAN APPLY TO FEATURE OF SIZE
LOCATION SYMMETRY Symmetry YES RFS ALWAYS
LOCATION POSTIONAL Positional YES AND NO LMC or MMC CAN APPLY TO FEATURE OF SIZE
LOCATION CONCENTRICITY Concentricity YES RFS ALWAYS
RUNOUT CIRCULAR RUNOUT Circular Runout YES RFS ALWAYS
RUNOUT TOTAL RUNOUT Total Runout YES RFS ALWAYS
ADDITIONAL GEOMETRIC TOLERANCING SYMBOL CHART ASME Y14.5M And ISO/TC 213
DESCRIPTION SYMBOLS REFERENCES
MAXIMUM MATERIAL CONDITION (MMC) MMC ISO 2692/ASME
LEAST MATERIAL CONDITION (LMC) LMC ISO 2692/ASME
REGARDLESS OF SIZE FEATURE (RFS) RFS ISO/ASME
SPHERICAL DIAMETER (SD) SD ISO/AMSE
RADIUS Radius ISO/ASME
DIAMETER Diameter ISO/ASME
ENVELOPE REQUIREMENT Envelope ISO/ASME
FREE STATE CONDITION (NON RIGID PARTS) Free State ISO 10579/ASME
MINOR DIAMETER Minor Diameter ISO/ASME
MAJOR DIAMETER Major Diameter ISO/ASME
PITCH DIAMETER Pitch Diameter ISO/ASME
COMMON ZONE Common Zone ISO/ASME
EXACT DIMENSION Exact Position ISO/ASME
DIMENSION ORIGIN Dimension Origin ISO/ASME
ALL ROUND (PROFILE) All Round ISO NONE/ASME
DATUM FEATURE INDICATION Datum Feature ISO/ASME
DATUM TARGET INDICATION Datum Target ISO 5459
PROJECTED TOLERANCE ZONE Projected Zone ISO 10578/ASME