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GEOMETRIC DIMENSIONING AND TOLERANCING
Applications and Techniques for Use in Design, Manufacturing, and Inspection

Lesson 1 of 12: The Major Principles

This 70 minute CD-ROM or DVD covers the major principles of geometric tolerancing. While tolerancing a simple 2-part assembly, Jim Meadows discusses the following topics: 

    • Plus and Minus Tolerancing as it Relates to Profile and Position Tolerancing 

    • Converting from Plus and Minus to Position Tolerancing to Avoid Ambiguities 

    • Selecting Datum Features  

    • Tolerancing Datum Features  

    • General Rules of Tolerancing  

    • Calculating Geometric Tolerances  

    • Worst Case Boundaries for Tolerancing Analysis  

    • Minimum Wall Thickness Calculations  

    • Maximum and Least Material Conditions  

    • Virtual and Resultant Conditions  

    • Basic Dimensions and Where Their Tolerances Come From  

    • How to Tolerance without Too Much Symbology  

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 Lesson 2 of 12: Tolerancing Mating Parts in a Rotating Assembly

This 63 minute CD-ROM or DVD is a powerful learn-while-doing training session. 

    While tolerancing a crankshaft and coupling assembly, Mr. Meadows discusses the following topics:

    • Criteria for Optimum Datum Feature Selection  

    • Form Controls for Assembly and Inspection Repeatability  

    • Orientation Controls for Datum Feature Interrelationships  

    • The Definition and Use of Positional Controls  

    • How to Calculate and Distribute Tolerances throughout an Assembly  

    • Tolerancing for Assemblability and Balance  

    • The Difference between Bonus Tolerance and Pattern Shift  

    • The Effect of Maximum Material Condition Symbols after Datum Features of Size and Uniformity of Assembly Airspace and Balance in a Rotating Assembly  

    • Tolerancing Threaded Holes and the Use and Inspection of Projected Tolerance Zones  

    • What the Geometric Characteristics Really Control 

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 Lesson 3 of 12: Direct vs. Indirect Datum Structures

This 50 minute CD-ROM or DVD explores various datum structures and their effect on the availability of tolerances while tolerancing a three-part assembly. Topics discussed include 

    • Direct vs. Indirect Functional Relationships  

    • Tolerancing for Producibility and Functionality  

    • The Goal of Datums in Inspection and Assembly  

    • How to Choose between Datum Structures  

    • How to Mathematically Calculate the Feasibility of Various Datum Schemes 

    • Consistency in Geometric Controls from Part to Part in an Assembly  

    • Weighing One Geometric Control Against Another for Suitability  

    • How to Spot Similarities in Dissimilar Part Configurations  

    • How to Lower Cost without Adversely Affecting Functionality and Ability to Assemble Mating Features  

    • Comparison of Coaxiality Controls and How to Choose Between Them 

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Lesson 4 of 12: The Basics of Symbology

This 46 minute CD-ROM or DVD covers the meaning of, and various inspection procedures for, controls of form, orientation, profile, runout and location. It addresses the basic questions of: "What does it mean?" and "How do I inspect it?" Topics discussed include: 

    • Straightness  

    • Flatness  

    • Perpendicularity  

    • Parallelism  

    • Angularity  

    • Dimension Origin vs. Profile of a Surface  

    • Circularity, Cylindricity, Circular Runout  

    • Total Runout  

    • Compound Datums and Concentricity 

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Lesson 5 of 12: Allowed vs. Actual Deviation from True Position:  Bonus Tolerancing and Virtual Condition Boundaries

This 38 minute CD-ROM or DVD uses imagery and storytelling to convey the functional reasons behind the growth of geometric tolerance zones as features are produced at varying sizes. It covers the logic of the concept of Maximum Material Condition and the functional worst mating boundaries created and protected.    This session is a combination of calculations to determine how far from perfect a feature has been produced versus how far from geometric perfection it may stray before it fails to function. Topics discussed include: 

    • Calculating Bonus Tolerances  

    • How to Read a Feature Control Frame to Determine Part Function  

    • Calculating Actual Deviation from True Position  

    • Determining if Features have Violated their Geometric Tolerances  

    • Assessing Spherical Features for Compliance with Spherical Tolerance Zones  

    • Protecting Virtual Condition Boundaries, and  

    • How Additional Geometric Tolerances Derived from Feature Size Limits Relate to Worst Mating Condition Boundaries 

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Lesson 6 of 12: Profile, Flexible Parts and Datum Targets

This 74 minute CD-ROM or DVD uses a wide variety of complex geometric configurations to show the viewer how to choose datums and tolerancing schemes for sheet metal and plastic parts as well as other parts with multiple curvatures and angles. It discusses free state variation and restrained versus free state inspection requirements. Topics discussed include: 

    • Profile of a Line  

    • Profile of a Surface  

    • Unilateral, Equal Bilateral and Unequal Bilateral Profile Tolerances  

    • Varying Tolerances from Segment to Segment on Surfaces  

    • Inspection Procedures for Profile Controls  

    • Basic Dimensions for Size, Shape, Angle, and Location Toleranced by Profile  

    • All Around and All Over Controls  

    • Eliminating Tolerance Accumulation  

    • Tolerancing Curved Mating Features for Fit  

    • Measuring Parts as They Function  

    • Implying a Manufacturing Sequence  

    • Simultaneous vs. Separate Gaging Requirements  

    • Pattern Shift with Simultaneous Requirements  

    • Orienting all Part Features to Each Other  

    • Amoebae Shaped Parts  

    • Fixturing and Stabilizing Parts in Presses  

    • Patterns of Features as Datums  

    • Compound Pattern Datums  

    • Poka-yoke (Foolproofing)  

    • Fixtures as Gages  

    • Functional Gage Tolerancing  

    • Datum Targets  

    • Points, Lines and Areas  

    • Dimension Origin Controls  

    • Step Datums  

    • Castings and Draft Angle  

    • Sheet Metal/Complex Flexible Parts  

    • Plastic Parts  

    • Restrained vs. Free State Requirements  

    • Boundary Concept  

    • Automobile Panels  

    • P.C. Boards 

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Lesson 7 of 12: Tolerancing Fixed Fastener Assemblies and Calculating Boundaries 

This 52 minute CD-ROM or DVD helps the viewer to become comfortable with calculating geometric tolerances for mating features in fixed fastener assemblies.   It shows all pertinent formulas and relates the process of part tolerancing and geometric control sequencing to manufacturing and gaging procedures.     As with almost every session in this series, this session is completely applications-based.    The participant learns by doing.    Topics discussed include: 

    • Calculating Geometric Tolerances for Mating Features in Assemblies  

    • How to Relate the Job of Tolerancing to Manufacturing Procedures  

    • How to Design Gages to Inspect Geometric Part Definitions  

    • How Visualizing Gages Can Help to Understand Functionality  

    • How to Read Feature Control Frames as though they were Sentences Describing How Parts Function 

    • Shifting Patterns of Mating Features vs. Growing Tolerance Zone Sizes  

    • Fixed Fastener Situations and How to Tolerance them  

    • How to Rework Parts to bring Them into Tolerance 

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Lesson 8 of 12: Tolerancing Floating Fastener Assemblies With Two Single-Segment Positional Controls 

This 48 minute CD-ROM or DVD focuses on the logic of datum feature selection and the cost-effective use of multi-level positional controls.    Using a floating fastener assembly with radial hole patterns, Mr. Meadows introduces the methodical process of applying deductive reasoning to optimize geometric product definition.  Topics discussed include: 

    • What a Floating Fastener Situation Is  

    • How to Calculate the Tolerances  

    • Selecting the Best Datum Features  

    • The Four Criteria for Datum Selection  

    • Line Geometry/Relating Axes Radially to a Datum Axis for Angle and Distance 

    • Considering All Spatial Degrees of Freedom  

    • Rotation and Translation of Axes  

    • Implied vs. Specified Datums  

    • Datums for Ease of Part Setup during Inspection  

    • The Logical Selection of Each Geometric Control and Datum Feature for Ease of Manufacture  

    • Geometric Definition for a Sensible Manufacturing Sequence  

    • Datum Feature Accessibility  

    • Refining and Optimizing Geometric Controls for Greater Yields  

    • The Two-Step Approach for Functionality and Cost Reduction  

    • Datum Features at Maximum Material Condition  

    • Equal vs. Unequal Airspace in Assemblies  

    • Two Single-Segment Positional Controls  

    • Moving Tolerance Zones within Stationary Tolerance Zones  

    • Composite vs. Two Single-Segment Positional Controls  

    • Separately Verifiable Controls  

    • Zero Positional Tolerancing at Maximum Material Condition 

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Lesson 9 of 12: Tolerancing Complex Assemblies with Multi-Level Geometric Controls and Varying Datum Structures 

This 59 minute CD-ROM or DVD focuses on the application of appropriate datum structures and geometric tolerances to a part that is both challenging and realistic.   Participants are treated to a detailed analysis of the optimal use of datums and geometric controls that escalate in sophistication as the product definition progresses from beginning to end. 

    Form, orientation  and location  controls are added in what  is determined  to  be the most functional and producible approach possible.      Tolerances are calculated and distributed between three parts in this assembly.     Geometric controls are converted to  multi-level/two single-segment  controls for  cost reduction and compatible mating conditions.    Tolerances are analyzed and minimum wall thicknesses protected. 

    New formulas are introduced for analysis and worst case boundaries for the first time in this session.    Datum structures are changed for direct tolerancing relationships throughout the assembly for ease of manufacture, functional inspection and to produce the greatest yield of functional parts. This session is jam-packed with new information and reinforcement of previously discussed concepts.    Exciting and fun! 

    [NOTE: This CD-ROM or DVD discusses some of the most critical and difficult concepts of geometric definition.     We recommend viewing it in sequence to avoid confusion.] 

    Topics discussed are: 

    • Varying Datum Structures  

    • Multi-Level Geometric Controls  

    • Projected Tolerance Zones for Threaded Holes  

    • Manufacturing Sequencing through Geometric Symbology 

    • Form, Orientation and Location Controls Properly Sequenced  

    • Distributing Tolerances Throughout the Assembly  

    • Pattern Shift with Datum Features at Maximum Material Condition  

    • Tight Tolerances to Critical Datums and Looser Tolerances to Less Critical Datums  

    • Multiple Virtual Condition Boundaries  

    • Minimum Wall Thickness Calculations  

    • The Key Questions to Ask That Lead One to the Optimum Controls  

    • Two Single-Segment Positional Controls vs. Composite Positional Tolerancing 

    • Zero Positional Tolerancing at MMC  

    • Linear Logic of Geometric Product Definition 

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Lesson 10 of 12: Composite vs. Two Single-Segment Controls for Position and Profile

This 63 minute CD-ROM or DVD addresses a wide variety of new and complex  geometric principles found in the latest revision of  ASME Y14.5M-1994.    The most sweeping change in this new standard is the redefinition of Composite Tolerancing and the added concept of Two Single-Segment Controls for Position and their extension to the concept of Profile Tolerancing.   This session  devotes its attention to thoroughly explaining each control, the rules, the differences and how they can accomplish geometric control never before available.   It also employs the deductive reasoning skills of participants to logically deduce the meaning of these controls on complex part configurations.   Topics discussed include: 

    • Composite Positional Tolerancing  

    • Feature Relating Tolerance Zone Frameworks  

    • Pattern Locating Tolerance Zone Frameworks  

    • The Dreaded Hypotenuse Effect  

    • Rotating Patterns of Tolerance Zones  

    • Composite Tolerancing and Orientation Only Datums  

    • Two Single-Segment Positional Controls  

    • Tighter Tolerances of Distance to One Datum Only  

    • The Essence of Position  

    • How to Keep One Set-up for Multiple Controls  

    • Position without Datums  

    • The Relative Strength of Various Geometric Characteristics  

    • Tolerance Zone Paths of Movement vs. Tolerance Zone Configurations  

    • ASME Y14.5M-1994 vs. ANSI Y14.5M-1982  

    • Deductive Reasoning on Complex Geometries  

    • Radial Hole Patterns  

    • Slots as Angular Orientation Datums  

    • The Logic of Geometric Tolerancing  

    • The Strict Rules of Composite Tolerancing  

    • Centerplane Datums and Their Set-up for Simulation  

    • The Essence of Profile  

    • Profile All-Around  

    • Composite Profile Tolerancing  

    • Multiple Tolerance Zones for Irregular Features  

    • Two-Single-Segment Profile Controls 

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Lesson 11 of 12: Converting from Plus And Minus To Composite Position and Wall Thickness Calculations 

This 73 minute CD-ROM or DVD is an applications-based training session that uses a variety of assemblies and part geometric configurations to show participants how to convert from plus and minus tolerancing to Composite Positional Tolerancing.    It also shows how to calculate functional and cost-saving geometric tolerances, then analyze the tolerances for clearance, interference and minimum wall thickness.

    Topics discussed include: 

    • The Ambiguity of Plus and Minus tolerancing  

    • Floating Fastener Situations  

    • Establishing Functional Datum Features  

    • Tighter Tolerances Between Features Within a Pattern than to the Datums  

    • Converting from Plus and Minus to Composite Positional Tolerancing  

    • Criteria for Datum Precedence and Usage  

    • Tolerance Zone Descriptions  

    • Material Condition Symbols  

    • What Each Level of Control Tolerances  

    • Calculating and Testing Tolerances  

    • Bonus Tolerances  

    • Determining Geometric Tolerances and Calculating Minimum Wall Thickness  

    • Setting Minimum Wall Thickness, then Calculating Pattern Locating Geometric Tolerances from Them  

    • Zeroing Out a Composite Positional Control for Greater Yields  

    • Redistributing Tolerances Between Size Limits and Geometric Controls  

    • The Effect of Size on Form and Wall Thickness  

    • Angular Tolerances and How They Effect Wall Thickness  

    • Optimizing Complex Controls Without Changing the Worst Case Boundaries  

    • Differences Between Composite Position and Two-Single-Segment Positional Controls  

    • Problem and Causal Statements  

    • Sequential Controls of Form and Orientation for Geometric Definition and Problem Solving  

    • Making Tolerance Analysis Easy  

    • Positional Coaxiality  

    • Centerplane Datums  

    • Position With and Without Datums 

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Lesson 12 of 12: Complex Tolerancing Using Various Datum Structures

This 73 minute CD-ROM or DVD explores a wide variety of datum structures for ease of set-up in manufacturing and inspection and optimal interrelationships of functional features.   It discusses patterns of holes used to create datum reference frames.  It demonstrates the enormous power of creating simultaneous gaging requirements. 

    Participants are taught to use geometric controls and datum structures to dimension 
    and tolerance complex curved surfaces that mate with other complex curvatures, while additional features such as holes and shafts must simultaneously mate. 

    Centerplane and centering mating features on parts in an assembly are also shown.  All concepts are reinforced through problem solving using a logical approach to geometric tolerancing.   Topics discussed include: 

    • Profile of a Surface on an Irregular Surface  

    • Positioning of Hole Patterns  

    • Datum Targets  

    • Direct vs. Indirect Relationships  

    • Patterns of Holes as Datum Features  

    • Virtual Condition Boundaries  

    • Unilateral Profile Tolerancing All-Around Controls  

    • Centroids of Revolution of Groups of Features  

    • Methods of Profile Inspection  

    • Secondary and Tertiary Datum Features of Size  

    • The Relative Power of Various Datum Structures  

    • Angular Orientation  

    • Compound Datum Features of Size vs. Secondary and Tertiary Datum Holes 

    • Datum Structuring for Ease of Inspection  

    • Fixturing and Gaging Visualization Techniques for Geometric Understanding  

    • Immobilizing all Spatial Degrees of Part Freedom  

    • The Power of Datum Precedence  

    • Gage Pin Configurations/Cylindrical vs. Diamond  

    • Compound Planar Datum Features  

    • Coplanarity  

    • Simultaneous Gaging Requirements to Gain Direct Geometric Relationships  

    • Creative Tolerancing Schemes for Ease of Inspection and Optimal Power of Interrelationship  

    • Indicating Specific Features for Clarity of Control  

    • Pattern Shift Because of Datum Features Referenced at Maximum Material Condition  

    • Separate Gaging Requirements  

    • Sequential Creation of Geometric Definitions  

    • Interrelating All Datum Features Before Using Them in Tandem 

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