GD&T Fundamentals

Table of Contents

1. Introduction
   1. Introduction to GD&T
2. GD&T Terminology
   1. Types of Surfaces
      1. Opposed Surfaces
      2. Partially Opposed Surfaces
      3. Non-Opposed Surfaces
   2. Axis, Planes, and Lines of a Feature
      1. Axis
      2. Center Plane
      3. Derived Median Line
      4. Derived Median Plane
   3. Types of Features
      1. Feature
      2. Feature of Size
      3. Regular Feature of Size
      4. Irregular Feature of Size
   4. Dimensions of a Feature
      1. Size Dimension
      2. Actual Local Size
      3. Basic Dimension
   5. Mating Envelopes
      1. Actual Mating Envelope
      2. Unrelated vs. Related Actual Mating Envelope
3. Engineering Drawing Symbols
   1. Geometric Characteristic Symbols
      1. Form
      2. Orientation
      3. Location
      4. Runout
      5. Profile
   2. General Dimension Modifying Symbols
      1. Spherical Diameter
      2. Controlled Radius
      3. Spherical Radius
      4. Square Symbol
      5. Dimension Origin
      6. Continuous Feature
      7. Independency
   3. Feature Modifying Symbols
      1. Material Condition Modifiers
         1. Maximum Material Condition
         2. Least Material Condition
         3. Regardless of Feature Size
   4. Geometric Tolerance Modifiers
      1. Projected Tolerance Zone
      2. Statistical Tolerance
      3. Free State
      4. Between
      5. All Around
      6. All Over
      7. Tangent Plane
      8. Unequally Disposed Profile
      9. Non-Uniform Profile
   5. Feature Control Frame
4. GD&T Rules
   1. Rule #1
      1. Exceptions to Rule #1
      2. How to Override Rule #1
      3. Purpose of Rule #1
      4. Examples of Rule #1
   2. Rule #2
      1. Purpose and Applications of Rule #2
      2. Effect of RFS
         1. Examples of Effect of RFS
      3. Effect of MMC or LMC (Bonus Tolerance)
      4. Effect of Zero Geometric Tolerance at MMC or LMC
         1. Determining Bonus Tolerance with Zero Tolerance
         2. Maximum Value Specified
   3. Boundary Conditions for Features of Size
      1. Effect of RFS on Boundaries
         1. Inner Boundary and Outer Boundary
         2. Inner Boundary for an External Feature of Size
         3. Outer Boundary for an External Feature of Size
         4. Inner Boundary for an Internal Feature of Size
         5. Outer Boundary for an Internal Feature of Size
   4. Effect of MMC or LMC on Boundaries
      1. Virtual Condition and Resultant Condition
      2. Virtual Condition for an External Feature of Size
      3. Resultant Condition for an External Feature of Size
      4. Virtual Condition for an Internal Feature of Size
      5. Resultant Condition for an Internal Feature of Size
5. Datum System
   1. Datums
   2. Datum Features
      1. Datum Feature Selection
      2. Datum Feature Designation
      3. Datum Features in the Feature Control Frame
      4. Controlling Datum Features
      5. Additional Datum Terms
         1. Datum Axis
         2. Coaxial Datum Features
         3. Datum Center Plane and Datum Center Point
   3. Boundary Conditions for Datum Features
      1. Maximum Material Boundary
      2. Least Material Boundary
      3. Regardless of Material Boundary
      4. Effect of RMB
      5. Effect of MMB or LMB (Shift Tolerance)
         1. Examples of Effect of MMB or LMB
   4. Datum Feature Simulator
      1. Datum Feature Simulator Identification
      2. Datum Feature Simulator Requirements
      3. Theoretical vs. Physical Datum Feature Simulators
   5. Degrees of Freedom
      1. Constraining the Degrees of Freedom
      2. Constraining DOFs for Primary Datum Features
         1. Planar Surface
         2. Width Element
         3. Cylindrical Surface
         4. Spherical Surface
         5. Conical Surface
         6. Slot Feature
         7. Complex Feature
   6. Datum Reference Frame
      1. Number of DRFs per Print
      2. Establishing DRFs
   7. Datum Target
      1. Datum Target Identification
      2. Datum Target Selection