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

Table of Contents

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
    • Controlled Radius
    • Spherical Radius
    • 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

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