Fundamentals of Geometric Dimensioning & Tolerancing (GD&T)

Geometric dimensioning and tolerancing (GD&T) is used as a symbolic way of showing specific tolerances on drawings. GD&T is a valuable tool that effectively communicates the design intent to manufacturing and inspection. It is governed by the technical standard ASME Y14.5-2009. This course introduces participants to the GD&T system, providing a working knowledge of the correct interpretation and application of each symbol, general rules, the datum system, and 'bonus' tolerance and highlighting some of the changes in the updated Y14.5 standard. The material is reinforced with many practice exercises.

What Will You Learn

By participating in this web seminar, you will be able to:
  • Explain the benefits of geometric tolerancing
  • Identify datum features and determine their order of precedence
  • Identify and interpret each of the characteristic symbols
  • Describe the material condition modifiers and how "bonus" tolerance occurs
  • Correctly interpret GD&T feature control frames, and explain the impact on manufacturing and inspection

Is This Course For You

This course is ideal for anyone who has a need to apply or interpret geometric tolerances on a product print. Product engineers, manufacturing engineers, CAD designers, quality inspectors, and other engineering and manufacturing personnel will all benefit from a better understanding of design requirements; improved communication with customers and suppliers; and improving designs by taking advantage of bonus tolerance and other GD&T benefits. Participants should have an understanding of basic blueprint reading. If you already are applying basic GD&T concepts, you may be interested in the advanced competency courses in the GD&T Web Seminar Series.


This course satisfies a requirement in the Product Engineering Tools and Methods Certificate Program.

Materials Provided

This data is not available at this time

Course Requirements

*Global toll-free telephone numbers are provided for many countries outside the U.S., but are limited to those on the WebEx call-in toll-free number list. Check here to see if your country has a global call-in toll free telephone number for this web seminar. If your country is not listed, you may still connect using the US/Canada Call-in toll number or Voice over Internet Protocol (VoIP).

Although WebEx Training Manager will automatically launch when you join the web seminar, you or your system administrator are encouraged to download the plug-in in advance to help ensure successful setup. Click here, then follow the onscreen instructions.


Session 1
  • Why Use GD&T?
    • Review of traditional dimensioning
    • Benefits of GD&T
    • Technical standards
    • Definitions
    • Basic dimensions
    • How to read the feature control frame

Session 2
  • Rules and the Form Symbols
    • Rule #1: Size controls form
    • Rule #2: Assume RFS
    • Flatness
    • Surface straightness
    • Circularity
    • Cylindricity

Session 3
  • Bonus Tolerance
    • GD&T applied to a feature of size
    • Bonus and the MMC modifier
    • Virtual condition
    • Gaging and inspection of GD&T

Session 4
  • Datums
    • Datum vs. datum feature
    • The datum reference frame
    • Primary, secondary, and tertiary datums

Session 5
  • Profile and Orientation
    • General definition of profile
    • Profile of a line
    • Profile of a surface
    • Use of datums with profile
    • Perpendicularity
    • Angularity
    • Parallelism

Session 6
  • Position Tolerance I
    • True position
    • Position tolerance RFS
    • Using MMC or LMC
    • The "boundary" concept
    • The pitch diameter rule

Session 7
  • Position Tolerance II
    • Projected tolerance zone
    • Inspecting parts for position
    • Calculating tolerance values
    • Composite position tolerance

Session 8
  • Symmetry and Coaxial Controls
    • Concentricity
    • Symmetry
    • Circular runout
    • Total runout
  • Wrap-up