Basic Geometric Dimensioning and Tolerancing
ASME Y14.5:2009

Geometric dimensioning and tolerancing (GD&T) is a symbolic language used on engineering drawings and computer generated three-dimensional solid models for explicitly describing nominal geometry and its allowable variation. Geometric dimensioning and tolerancing training is used to define the nominal geometry of parts and assemblies, to define the allowable variation in form and possibly size of individual features, and to define the allowable variation between features (Wikipedia). Course instruction will be to standard ASME Y14.5-2009


16 hours


Upon completion of this course, the participant will be able to:

  • Define terminology and symbology
  • Understand rules and concepts
  • Calculate material conditions
  • Interpret tolerance zones for GD&T applications
  • Understand inspection requirements

Introduction to Geometric Dimensioning and Tolerancing

  1. Terminology and Symbols
  2. Feature Control Frame
  3. Features and Features of Size
  4. Material Conditions (MMC, LMC, RFS)
  5. Rule Number One
  6. Rule Number Two
  7. Basic Dimensions
  8. Virtual Condition

ASME Y14.5 Standard

  • General Rules
  • Symbols
  • Modifiers (MMC, RFS, LMC)
  • Datums
  • Tolerance Zones
  • Virtual Condition/Size

Form Tolerances

  • Review
  • Flatness
  • Straightness
  • Circularity (Roundness)
  • Cylindricity

Orientation Tolerances

  • Review of datums
  • Secondary Alignment datums
  • Parallelism
  • Perpendicularity
  • Angularity

Runout Tolerances

  • Introduction
  • Definition of Runout
  • Circular Runout
  • Total Runout

Profile Tolerances

  • Introduction to Profile
  • Bilateral/Unilateral zones
  • Basic dimensions
  • Profile of a Line
  • Profile of a Surface
  • Profile – Coplanar Surfaces
  • Locating a surface

Location Tolerances

  • Position Tolerances
  • Introduction & Basic dimensions
  • Position Vs Coordinates
  • Conversion
  • Bonus tolerances
  • Functional gages
  • Hole Patterns
  • No datum
  • Primary datum only
  • All three datums
  • Composite tolerances
  • Functional Gaging
  • Bonus tolerance
  • Base line & Chain dimensioning
  • Position Coaxial
  • Position at LMC
  • Bi-Directional Position
  • Position -Size Datums
  • Graphical Inspection Analysis
  • Projected Tolerance Zones


  • Conc. versus Runout
  • Measuring methods
  • Verifying concentricity