# GD&T Fundamentals

The GD&T Fundamentals course is an informative, advanced-level course introducing learners who have a thorough understanding of how to read and interpret engineering drawings to the fundamentals of geometric dimensioning and tolerancing (GD&T). In this course, learners are provided with an introduction to the key terminology used within the language of GD&T, the major symbols, the essential rules, and the datum systems used in GD&T. The concepts covered in this course are based on the ASME Y14.5: 2009 standard.

### Learning Objectives

• Recognize the key GD&T terminology and comprehend the applied meaning of each.
• Identify the engineering drawing symbols most closely associated with GD&T.
• Distinguish between and understand the implications of Rule #1 and #2 of GD&T.
• Understand the effect of material modifiers.
• Differentiate between datums, datum features, and the parts of datum systems.
• Calculate bonus tolerance and shift tolerance.
`Course Length: 6 HRS`

#### Terminology

• Types of Surfaces
• Opposed Surfaces
• Partially Opposed Surfaces
• Non-Opposed Surfaces
• Axis, Planes, and Lines of a Feature
• Axis
• Center Plane
• Derived Median Line
• Derived Median Plane
• Types of Features
• Feature
• Feature of Size
• Regular Feature of Size
• Irregular Feature of Size
• Dimensions of a Feature
• Size Dimension
• Actual Local Size
• Basic Dimension
• Mating Envelopes
• Actual Mating Envelope
• Unrelated vs. Related Actual Mating Envelope

#### Engineering Drawing Symbols

• Geometric Characteristic Symbols
• Form
• Orientation
• Location
• Runout
• Profile
• General Dimension Modifying Symbols
• Spherical Diameter
• Square Symbol
• Dimension Origin
• Continuous Feature
• Independency
• Feature Modifying Symbols
• Maximum Material Condition
• Least Material Condition
• Regardless of Feature Size
• Projected Tolerance Zone
• Statistical Tolerance
• Free State
• Between
• All Around
• All Over
• Tangent Plane
• Unequally Disposed Profile
• Non-Uniform Profile
• Feature Control Frame

#### GD&T Rules

• Rule #1
• Exceptions to Rule #1
• How to Override Rule #1
• Purpose of Rule #1
• Examples of Rule #1
• Rule #2
• Purpose and Applications of Rule #2
• Effect of RFS
• Effect of MMC or LMC (Bonus Tolerance)
• Effect of Zero Geometric Tolerance at MMC or LMC
• Determining Bonus Tolerance with Zero Tolerance
• Maximum Value Specified
• Boundary Conditions for Features of Size
• Need for Boundary Conditions
• Effect of RFS on Boundaries
• Effect of MMC or LMC on Boundaries

#### Datum Systems

• Datums
• Datum Features
• Datum Feature Selection
• Datum Feature Designation
• Datum Features in the Feature Control Frame
• Controlling Datum Features
• Datum Axis
• Coaxial Datum Features
• Datum Center Plane and Datum Center Point
• Boundary Conditions for Datum Features
• Maximum Material Boundary
• Least Material Boundary
• Regardless of Material Boundary
• Effect of RMB
• Effect of MMB or LMB (Shift Tolerance)
• Datum Feature Simulator
• Datum Feature Simulator Identification
• Datum Feature Simulator Requirements
• Theoretical vs. Physical Datum Feature Simulators
• Degrees of Freedom
• Constraining the Degrees of Freedom
• Constraining DOFs for Primary Datum Features
• Planar Surface
• Width Element
• Cylindrical Surface
• Spherical Surface
• Conical Surface
• Slot Feature
• Complex Feature
• Datum Reference Frame
• Number of DRFs per Print
• Establishing DRFs
• Datum Target
• Datum Target Identification
• Datum Target Selection