To better define a product, geometric dimensioning and tolerancing (GD&T) is often used as a symbolic way of showing specific tolerances on drawings. GD&T is a valuable language that communicates the design intent to manufacturing and inspection. It is governed by the technical standard ASME Y14.5-2009. This course covers all aspects of GD&T. In addition to learning the theory, participants will see numerous examples that demonstrate specific applications. Participants are welcome to bring sample prints to the class for discussion or private consultation.

Class Details

Class Name:
Product engineers, inspectors, machinists, CAD designers, manufacturing engineers, tool and die makers, gage designers and makers, management personnel, and support staff who need to understand mechanical prints.
3 Day Course

Learning Objectives

After participating in this class, participants will be able to:

  • Describe the benefits of using geometric dimensioning and tolerancing.
  • Explain how Rule #1 imposes certain geometric controls automatically.
  • Identify whether a given feature is considered a surface or a feature of size.
  • Interpret feature control frames, and identify correct/incorrect syntax in a given feature control frame.
  • Calculate virtual condition and describe why it is important.
  • Define a basic dimension, and explain how it relates to GD&T.
  • Recognize the MMC modifier and calculate the appropriate bonus tolerance.
  • Describe the tolerance zone for each of the 14 GD&T symbols.
  • Correctly identify datum features and determine their order of precedence.
  • Determine proper inspection methods for a given GD&T callout.

Outline At-a-Glance

  • Review of coordinate dimensioning and tolerancing
  • How GD&T can improve a drawing
  • Overview of the Y14.5 standard
  • Surface vs. feature of size
  • Basic dimensions
  • Rule #1 – Size controls form
  • Definition of MMC, LMC, RFS
  • Reading the feature control frame
  • Virtual condition
  • Form tolerances
  • Datums
  • Datum targets
  • Simulating datums on fixtures and/or CMMs
  • Profile tolerances
  • Orientation tolerances
  • Location tolerances
  • Advanced location – projected zone, fixed/floating fasteners
  • Runout tolerances
  • Bridging the theory of GD&T with the real world
  • Discuss sample prints
  • Wrap-up

Job Roles