GD&T Trainer: Fundamentals 2009
Based
on ASME Y14.52009
Goals
and Objectives
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Lesson
1: Drawing Standards
Goal: Understand the importance of standards on engineering drawings.
 Describe
what an engineering drawing is
 Explain the importance of an engineering drawing
 List four consequences of engineering drawing errors
 List the two primary dimensioning and tolerancing standards used globally
 Describe which ASME standards cover dimensioning and tolerancing
 Describe the role of dimensioning and tolerancing standards on engineering drawings
 Identify which dimensioning and tolerancing standards apply to an engineering drawing
Lesson
2: Dimensions, Tolerances, and Notes Used on Drawings
Goal: Understand the types of dimensions, tolerances, and notes.
 Describe three purposes of dimensions and tolerances
 Identify which units of linear measurement apply on a drawing
 Explain the options for expressing units of angular measurement
 Explain three conventions used when metric units apply on a drawing
 Describe three conventions used for angular dimensions
 Describe what a dimension is
 Describe what a tolerance is
 Describe what a limit tolerance is
 Describe what a plusminus tolerance is
 Describe what an equal bilateral tolerance is
 Describe what an unequal bilateral tolerance is
 Describe what a unilateral tolerance is
 Interpret dimensional limits
 Describe local, flag, and general notes on drawings
 Describe why CAD models need to communicate permissible tolerances
 Describe how CAD models communicate permissible tolerances
Lesson
3: Coordinate Tolerancing and GD&T
Goal: Understand why geometric tolerancing is superior to coordinate tolerancing
 Describe what the coordinate tolerancing method is
 Explain the six major shortcomings of coordinate tolerancing
 Explain three potential consequences of using coordinate tolerances
 Describe three appropriate uses for coordinate tolerancing
 Describe what the geometric dimensioning and tolerancing (GD&T) system is
 Describe the design philosophy used with GD&T
 List the six major components in the GD&T language
 Describe where GD&T should be used
 List four benefits of GD&T
 Explain how GD&T eliminates the shortcomings of coordinate tolerancing
 Explain why the “great myth” of GD&T is untrue
Lesson
4: General Dimensioning Symbols
Goal: Understand the general dimensioning symbols
 Interpret the symbols for radius, spherical radius, and controlled radius
 Interpret the symbols for diameter and spherical diameter
 Interpret the symbol for square
 Interpret the symbols for counterbore and spotface
 Interpret the symbol for depth
 Interpret the symbol for countersink
 Interpret the symbol for number of places
 Interpret the symbol to indicate "by"
 Interpret MAX and MIN dimensions
 Interpret the symbol for reference
 Interpret the symbol for dimension origin
 Interpret the model coordinate system symbol
Lesson
5: Key GD&T Terms
Goal: Understand the key terms used in the GD&T language.
 Describe the terms "opposed," "partially opposed," and "nonopposed"
 Describe the terms "size dimension" and "actual local size"
 Explain why it is important to distinguish between a feature and a feature of size
 Describe the terms "feature" and "complex feature"
 Describe the terms "feature of size," "regular feature of size," and "irregular feature of size"
 Classify regular and irregular features of size and nonfeatures of size on a drawing
 Explain why it is important to distinguish between a regular and irregular feature of size
 Describe the terms "actual mating envelope," "related actual mating envelope," and "unrelated actual mating envelope"
 Describe the terms "maximum material condition," "least material condition," and "regardless of feature size"
 Calculate the maximum and least material condition of a feature of size
 Describe the term "pattern"
 List seven ways to specify a pattern on a drawing
Lesson
6: Symbols and Modifiers
Goal: Recognize the symbols and modifiers used in GD&T
 Identify the fourteen geometric characteristic symbols
 List the five types of geometric controls
 Identify the twentyone geometric modifying symbols
 Identify the parts of a feature control frame
 Identify feature control frames on a drawing
 Explain how the continuous feature modifier affects a feature and a feature of size
 Define a basic dimension
 List two uses for a basic dimension
 Describe where the tolerance for a basic dimension comes from
Lesson
7: GD&T Rules
Goal: Understand the rules used in GD&T
 Describe
the difference between derived median line and axis
 Recognize the 16 fundamental dimensioning rules used in GD&T
 Explain the impact of each fundamental dimensioning rule on a drawing
 Explain Rule #1
 Draw the Rule #1 boundary
 Determine where Rule #1 applies to a feature of size
 Explain how Rule #1 affects the interrelationship between features of size
 List two exceptions to Rule #1
 List three ways Rule #1 can be overridden
 Explain what a functional gage is
 Explain how to inspect a feature of size that is controlled by Rule #1
 Describe the independency concept
 Explain Rule #2
Lesson
8: GD&T Concepts
Goal: Understand the concepts of worstcase boundary, virtual condition, and bonus tolerance.
 Describe a worstcase boundary
 Describe the term "inner boundary"
 Describe the term "outer boundary"
 Explain the concept of virtual condition
 Identify the effect on the worstcase boundary where a geometric tolerance is applied to a feature or feature of size
 Calculate the virtual condition of a feature of size with GD&T applied
 Explain the concept of bonus tolerance
 Calculate the maximum permissible bonus tolerance for a geometric tolerance
Lesson
9: Flatness Tolerance
Goal: Interpret the flatness tolerance.
 Describe the terms "flatness," "derived median plane," and "flatness tolerance"
 Describe the tolerances zones for a flatness tolerance
 Describe Rule #1's effects on flatness deviation
 Describe the modifiers that may be used in a flatness tolerance
 Recognize when a flatness tolerance is applied to a planar surface or a feature of size
 Describe realworld applications of a flatness tolerance
 Interpret a flatness tolerance applied to a planar surface
 Interpret a flatness tolerance at RFS applied to a feature of size dimension
 Interpret a flatness tolerance at MMC applied to a feature of size dimension
 Understand flatness verification principles
 Describe how to verify a flatness tolerance applied to a planar surface
 Describe how to verify a flatness tolerance (at MMC) applied to a feature of size
Lesson
10: Straightness Tolerance
Goal: Interpret the straightness tolerance
 Describe the terms "straightness," "derived median line," and "straightness tolerance"
 Describe the tolerance zones for a straightness tolerance
 Describe Rule #1’s effects on straightness deviation
 Describe the modifiers that may be used with a straightness tolerance
 Determine if a straightness tolerance is applied to line elements or to a feature of size
 Describe realworld applications for a straightness tolerance
 Interpret the straightness tolerance applied to line elements of a cylindrical surface
 Interpret a straightness tolerance at MMC applied to a feature of size dimension
 Understand straightness verification principles
 Describe how to verify a straightness tolerance applied to the elements of a cylindrical surface
 Draw a functional gage for verifying a straightness at MMC application
Lesson
11: Circularity Tolerance
Goal: Interpret the circularity tolerance.
 Describe the terms "circularity," "spine," "circularity tolerance," and "minimum radial separation"
 Describe the tolerance zone for a circularity tolerance
 Describe how Rule #1 affects circularity deviation
 Describe the modifiers that may be used in a circularity
 tolerance
 Describe how to specify a circularity tolerance
 Describe realworld applications for a circularity tolerance
 Interpret a circularity tolerance applied to cylindrical surface
 elements
 Understand the verification principles for a circularity tolerance
 Describe how to verify a circularity tolerance
Lesson 12: Cylindricity Tolerance
Goal: Interpret the cylindricity tolerance.
 Describe the terms “cylindricity” and “cylindricity tolerance”
 Describe the tolerance zone for a cylindricity tolerance
 Describe Rule #1’s effects on cylindricity deviation
 Describe how to specify a cylindricity tolerance
 Describe the modifiers that may be used in a cylindricity tolerance
 Describe realworld applications for a cylindricity tolerance
 Interpret a cylindricity tolerance applied to a cylinder
 Understand the verification principles for a cylindricity tolerance
 Describe how to verify a cylindricity tolerance applied to the surface of a diameter.
Lesson
13: The Datum System
Goal: Understand the datum system.
 Describe an implied datum
 Describe the shortcomings and consequences of implied datums
 Describe the datum system
 Describe three benefits of the datum system
 Define the terms “datum,” “datum feature,” “datum feature simulator,” and “simulated datum”
 Recognize a datum feature symbol
 Describe the datum reference frame symbol
 Describe four ways to specify a planar datum feature
 Explain how datum features are referenced in feature control frames
 Describe the six degrees of freedom
 Define “constraint”
 Describe a datum reference frame
 Describe what controls relationships between datum features
 Describe the 321 Rule
 Explain the basis for selecting datum features
 Describe coplanar datum features
 Explain why multiple datum reference frames are used
 Explain the difference between datumrelated and nondatumrelated dimensions
Lesson
14: Datum Targets
Goal: Interpret Applications of Datum Targets.
 Describe datum targets
 Recognize the datum target symbols (datum target, movable datum target, datum target leader line, point, line, and area)
 Explain where datum targets should be used
 Describe how to establish a complete datum reference frame using datum targets
 Describe a datum feature simulator for a point datum target application
 Describe a datum feature simulator for a line datum target application
 Describe a datum feature simulator for an area datum target application
 Describe the datum feature simulator for datum targets applied to a nonplanar surface
 Interpret applications of datum targets applied to a partial surface, to offset parallel surfaces, on irregular surfaces, and using the movable datum target symbol
Lesson
15: Size Datum Features  RMB
Goal: Interpret size datum features (RMB).
 Describe the terms, “regardless of material boundary,” “datum axis,” “datum center plane,” “datum center point,” “coaxial diameters,” and “coaxial datum features”
 Describe common methods used to specify a feature of size as a datum feature
 Describe how to reference a feature of size datum feature at RMB
 Describe two effects of referencing a feature of size datum feature at regardless of material boundary (RMB)
 Describe the datum feature simulator and list the DOF constrained for external and internal cylindrical feature of size datum features (RMB primary)
 Describe the datum feature simulator and list the DOF constrained for external and internal planar feature of size datum features (RMB primary)
 Describe the datum feature simulator and list the DOF constrained for a planar surface primary and internal feature of size (RMB secondary)
 Describe the datum feature simulator and list the DOF constrained for a planar surface primary and internal feature of size (RMB secondary and tertiary)
 Describe the datum established from coaxial datum features of size referenced at RMB
 Describe the datum feature simulator for coaxial datum features of size referenced at RMB
Lesson
16: Size Datum Features  MMB
Goal: Interpret size datum features (MMB).
 Describe the term “maximum material boundary” (MMB)
 Describe two effects of referencing a datum feature at MMB
 Calculate the size of the datum feature simulator for a primary datum feature MMB
 Calculate the size of the datum feature simulator for secondary datum feature MMB
 Calculate the size of the datum feature simulator for tertiary datum feature MMB
 Describe the concept of datum feature shift
 Explain where datum feature shift is permissible
 Calculate the amount of datum feature shift permissible
 Determine when datum feature shift is or is not additive to a geometric tolerance
 Calculate the MMB of the datum feature simulator for a planar surface datum feature at MMB
 Describe the datum feature simulator and the DOF constrained for internal and external cylindrical feature of size datum features (MMB primary)
 Describe the datum feature simulator and the DOF constrained for internal and external width feature of size datum features (MMB primary)
 Describe the datum feature simulator for an internal feature of size (MMB secondary)
 Describe the datum feature simulator for an internal feature of size (MMB tertiary)
 Describe the datum feature simulator and the DOF constrained for coaxial datum features (MMB)
 Describe the datum feature simulator and the DOF constrained for a pattern of features of size (MMB)
 Analyze the effects that changing the datum reference sequence in a feature control frame has on the part and datum feature simulator
Lesson
17: Perpendicularity Tolerance
Goal: Interpret the perpendicularity tolerance.
 Describe what controls the tolerance on implied 90° angles
 Describe the terms “perpendicularity” and “perpendicularity tolerance”
 Describe two common tolerance zone shapes for a perpendicularity tolerance
 List three indirect perpendicularity tolerances
 Describe the modifiers that may be used in a perpendicularity tolerance
 Recognize when a perpendicularity tolerance is applied to a planar surface or a feature of size
 Interpret a perpendicularity tolerance with multiple datum references applied to a planar surface
 Describe realworld applications for a perpendicularity tolerance
 Interpret a perpendicularity tolerance applied to a planar surface
 Interpret a perpendicularity application that uses the tangent plane modifier
 Interpret a perpendicularity tolerance at RFS applied to a width
 Interpret a perpendicularity tolerance at MMC applied to a width
 Interpret a perpendicularity tolerance at MMC applied to a cylindrical feature of size
 Understand perpendicularity verification principles
 Describe how a perpendicularity tolerance applied to a surface is verified
 Draw a gage for inspecting perpendicularity applied to a feature of size (MMC)
Lesson
18: Parallelism Tolerance
Goal: Interpret the parallelism tolerance.
 Describe what controls the parallelism deviation between two parallel surfaces where no parallelism tolerance is specified
 Describe the terms “parallelism” and “parallelism tolerance”
 Describe two common tolerance zone shapes for a parallelism tolerance
 Recognize when a parallelism tolerance is applied to a planar surface or to a feature of size
 List two indirect parallelism tolerances
 Describe the modifiers that may be used in a parallelism tolerance
 Describe realworld applications for a parallelism tolerance
 Interpret a parallelism tolerance applied to a planar surface
 Interpret a parallelism application that uses the tangent plane modifier
 Interpret a parallelism tolerance at RFS applied to a diameter
 Interpret a parallelism tolerance at MMC applied to a diameter
 Understand parallelism verification principles
 Describe how a parallelism tolerance applied to a surface is verified
 Describe how to verify a parallelism tolerance at RFS applied to a feature of size
 Describe how to verify a parallelism tolerance at MMC applied to a feature of size
Lesson
19: Angularity Tolerance
Goal: Interpret the angularity tolerance.
 Describe the terms "angularity" and "angularity tolerance"
 Describe two common tolerance zone shapes for an angularity tolerance
 Recognize when an angularity tolerance is applied to a surface or to a feature of size
 List two indirect angularity tolerances
 Describe the alternative practice for using an angularity tolerance to control orientation
 List which modifiers should be used in an angularity tolerance
 Describe realworld applications for an angularity tolerance
 Interpret an angularity tolerance applied to a planar surface
 Explain the effect of using multiple datum references with an angularity tolerance
 Interpret an angularity application that uses the tangent plane modifier
 Interpret an angularity tolerance at RFS applied to a diameter
 Interpret an angularity tolerance at MMC applied to a diameter
 Understand verification principles for angularity
 Describe how an angularity tolerance applied to a surface is verified
 Describe a functional gage for verifying an angularity tolerance at MMC
Lesson 20: Position Tolerance  Introduction
Goal: Interpret the position tolerance.
 Describe the terms “true position” and “position tolerance”
 Describe the geometry attributes that a position tolerance can affect
 Describe two common tolerance zone shapes for a position tolerance
 List the requirements of a position tolerance
 Describe the modifiers that can be used with a position tolerance
 Explain when each material condition modifier (MMC, LMC, or RFS) should be used in a position tolerance
 Explain the surface interpretation for a position tolerance
 Explain the axis/center plane interpretation for a position tolerance
 List six advantages of using a position tolerance
 Describe four types of feature of size relationships commonly toleranced with a position tolerance
Lesson 21: Position Tolerance  RFS and MMC
Goal: Interpret position tolerance applications RFS and MMC.
 List five conditions that apply where a position tolerance is
 indicated at RFS
 List five conditions that apply where a position tolerance is indicated at MMC
 Describe realworld applications for position tolerances
 Interpret a position tolerance at RFS applied to a hole
 Interpret a position tolerance at RFS applied to a slot
 Interpret a position tolerance at RFS applied to coaxial diameters
 Interpret a position tolerance at RFS applied to a pattern of holes
 Interpret a position tolerance at MMC applied to a hole
 Interpret a position tolerance at MMC applied to coaxial diameters
 Interpret a position tolerance at MMC applied to a pattern of holes
 Understand the verification principles for position tolerances
 Describe how to inspect a position tolerance (RFS)
 Describe how to inspect a position tolerance (MMC)
Lesson 22: Position Tolerance  Special Applications
Goal: Interpret special applications of position tolerances.
 Describe
the term "projected tolerance zone"
 Describe a realworld application of the projected tolerance zone modifier
 Interpret a position tolerance using the projected tolerance zone modifier
 Describe how a position tolerance with the projected tolerance zone modifier can be verified
 Describe what a multiple singlesegment position tolerance is
 Describe a realworld application of a multiple singlesegment position tolerance
 Interpret a multiple singlesegment position tolerance
 Describe what a composite position tolerance is
 Describe a realworld application of a composite position tolerance
 Interpret a composite position tolerance
 Interpret a position tolerance applied to a hole (MMC) at an angle to the datums
 Interpret a position tolerance used as a bidirectional tolerance
 Interpret a position tolerance applied to an elongated hole
 Interpret a position tolerance used to tolerance a symmetrical relationship
 Interpret a position tolerance using the LMC modifier
 Interpret a position tolerance used to tolerance the spacing and orientation of a hole pattern
 Explain what zero tolerance at MMC tolerancing is
 List three benefits of zero tolerance at MMC dimensioning
 Describe a realworld application for using zero tolerance at MMC
 Interpret a zero tolerance at MMC position application
Lesson
23: Position Tolerance Calculations
Goal: Calculate position tolerance values using the fixed and floating fastener formulas.
 Describe
a fixedfastener assembly
 State the general fixed fastener formula for calculating position tolerance values (with equal distribution)
 Calculate the position tolerance values for a fixed fastener application using the general fixed fastener formula
 State the modified fixed fastener formula for calculating position tolerance values (with unequal distribution)
 Calculate the position tolerance values for a fixed fastener application using the modified fixed fastener formula
 Describe a floating fastener assembly
 State the formula for calculating position tolerance values for floating fastener assemblies
 Calculate the position tolerance values for floating fastener applications
 Describe the limitations of the fixed and floating fastener formulas
Lesson
24: Circular Runout Tolerances
Goal: Understand how to interpret the circular runout tolerance.
 Describe
what runout is
 List two types of runout tolerances
 List three ways a datum axis can be specified for a runout tolerance
 Explain what circular runout is
 Describe the tolerance zone for a circular runout tolerance (applied to a diameter)
 Describe how circular runout can be inspected
 Describe how circular runout is a composite tolerance
 Determine the maximum amount of axis offset from a circular runout tolerance
 Interpret a circular runout application
 Describe two common applications for circular runout
Lesson
25: Total Runout Tolerances
Goal: Understand how to interpret the total runout tolerance.
 Describe
what total runout is
 List two requirements of a total runout tolerance
 Describe the tolerance zone for a total runout tolerance (applied to a diameter)
 Describe how total runout is verified
 Describe how total runout is a composite control
 Determine the maximum amount of axis offset from a total runout control
 Describe two similarities between circular and total runout
 Describe two differences between circular and total runout
 Describe two common applications for total runout
Lesson
26: Concentricity Tolerance
Goal: Interpret the concentricity tolerance.
 Describe
a median point
 Describe the term "concentricity"
 Describe the tolerance zone for a concentricity tolerance
 List three requirements of a concentricity tolerance
 Interpret a concentricity tolerance application
 Describe one difference between concentricity and tolerance of position (RFS)
 Describe one common application for concentricity
 Describe how a concentricity tolerance can be inspected
Lesson
27: Symmetry Tolerance
Goal: Interpret the symmetry tolerance.
 Describe the term "symmetry"
 Describe the tolerance zone for a symmetry tolerance
 List four requirements of a symmetry control
 Interpret a symmetry control application
 Describe one difference between symmetry and tolerance of position (RFS)
 Describe one common application for symmetry
 Describe how a symmetry control can be inspected
Lesson
28: Profile Tolerance  Introduction
Goal: Understand the basic concepts of the profile tolerances.
 Describe the terms "profile," "true profile," "profile of a surface tolerance," and "profile of a line tolerance"
 Describe the tolerance zone shape for profile of a surface and profile of a line tolerances
 Describe the geometry attributes that a profile tolerance can affect
 Explain the effect of using profile with or without datum references
 List the modifiers used with profile tolerances
 Describe bilateral, unilateral, and nonuniform tolerance zones
 Describe the effect of the unequally disposed profile symbol
 Describe the default condition for the extent a profile control tolerance zone applies to a part
 Describe the effect of the "between" symbol
 Describe the effect of the "all around" symbol
 Describe the effects of the "all over" symbol
 List three advantages of using profile tolerances
Lesson
29: Profile Tolerance Applications
Goal: Interpret profile tolerance applications.
 Describe realworld applications for a profile of a surface tolerance
 Interpret a profile of a surface tolerance applied to a planar surface
 Describe how to inspect a profile of a surface tolerance that is used to locate a planar surface
 Interpret profile of a surface applied to a closed polygon
 Interpret profile of a surface applied to a conical surface
 Interpret a profile tolerance applied to coplanar surfaces
 Describe what a multiple singlesegment profile tolerance is
 Interpret a multiple singlesegment profile control
 Describe what a composite profile tolerance is
 Interpret a composite profile tolerance
 Describe realworld applications for a profile of a line tolerance
 Interpret a profile of a line tolerance used with a dimension origin dimension to locate the surface
 Interpret a profile of a line tolerance application used to control orientation and form
 Understand the verification principles for profile tolerances
 Describe how to inspect a profile of a surface tolerance that is used to locate a planar surface
