Practical Geometric Tolerancing
Course Outline

GD and T Image The following MasterTask lesson outline indicates the primary tasks individuals will be able to perform upon completion of each lesson. Some of these tasks require the trainee to explain how something works to insure they have the required understanding of the processes and are not simply memorizing procedures. All of the tasks listed will be a part of the Performance Test within each lesson. To learn more about these tests and the training process itself, see the Philosophy section.

This MasterTask training system will enable trainees to read and interpret geometric tolerances, and to measure those tolerances on workpieces. The tolerances covered in this training system include the tolerances which are commonly applied to cylindrical (two-dimensional) workpieces, such as those manufactured on lathes, screw machines, and cold headers.

Lesson 1: Datums and True Position [ Top ]

After completing this lesson the trainee will be able to:

  1. Identify the following symbols and abbreviations on part prints:
    1. Feature Control Frame
    2. Datum Feature Symbol
    3. Common Datum Symbol
    4. True Position Symbol
    5. Basic Dimension
    6. Reference Dimension
  2. Name and describe the four categories of geometric tolerances:
    1. Location
    2. Form
    3. Runout
    4. Orientation
  3. Explain why measurements are made from datums.
  4. Describe the simulated datum and the theoretical datum which would apply to each of these types of datum features:
    1. Flat Surface
    2. Shaft or Hole
    3. Slot or Tab
  5. Define "Tue Position".
  6. Define "Basic Dimension".
  7. Describe the True Position tolerance zone for:
    1. Rectangular Parts (Hole Location)
    2. Cylindrical Parts (Coaxiality)
  8. Identify or describe the following using actual workpieces and measuring instruments:
    1. Datum Feature
    2. Simulated Datum
    3. Datum

Lesson 2: Material Condition Modifiers [ Top ]

After completing this lesson the trainee will be able to:

  1. Identify the following abbreviations and their symbols:
    1. MMC
    2. LMC
    3. RFS
  2. Define or describe the following:
    1. Maximum Material Condition
    2. Least Material Condition
    3. Regardless of Feature Size
    4. Bonus Tolerance
    5. Common applications of all three material condition modifiers
    6. The "boundary of perfect form at MMC"
  3. State the MMC and LMC size of features (OD or ID).
  4. Measure parts and calculate bonus tolerance from geometric tolerances.
  5. Measure parts and calculate bonus tolerance from datum features.
  6. Calculate total allowed tolerances.
  7. Identify all components of feature control frames including:
    1. Control Symbol
    2. Tolerance Amount
    3. Diameter Symbol
    4. Datum symbols

Lesson 3: Location Tolerances [ Top ]

After completing this lesson the trainee will be able to:

  1. Identify the following symbols on part prints:
    1. Concentricity
    2. Primary, Secondary, and Tertiary Datum Symbols
  2. Describe or explain the following:
    1. The four commonly used measuring methods:
      1. Functional Gages
      2. Open Setup Inspection
      3. Optical Comparator
      4. Coordinate Measuring Machine
    2. Why datums must be established in the order that they are listed in the feature control frame.
    3. The shape and dimensions of the position tolerance zone.
    4. The boundary of perfect form of position tolerances.
    5. The shape and dimensions of the concentricity tolerance zone.
    6. The material condition modifier(s) which are applied to position and concentricity tolerances.
  3. Perform the following tasks:
    1. Check OD and ID true position tolerances using functional gages.
    2. Measure true position using an optical comparator.
    3. Prepare a workpiece for measuring concentricity using:
      1. Precision Spindle
      2. Adjustable V-Blocks
      3. Single V-Blocks
      4. Tri-Roll
    4. Measure concentricity by measuring opposing points on the surface of a feature, then calculating the amount of axis deviation.

Lesson 4: Rotational Tolerances [ Top ]

After completing this lesson the trainee will be able to:

  1. Identify the following tolerance symbols on part prints:
    1. Roundness
    2. Cylindricity
    3. Circular Runout
    4. Total Runout
  2. Identify or describe the following:
    1. The shape and dimensions of the following tolerance zones:
      1. Roundness
      2. Cylindricity
      3. Circular Runout
      4. Total Runout
      5. Circular Face Runout
      6. Total Face Runout
    2. The material condition modifiers which may be applied to the above tolerances.
  3. Perform the following tasks:
    1. Prepare workpieces for measurement; prepare and time an indicator.
    2. Measure roundness.
    3. Measure cylindricity by first measuring the taper with a micrometer, then measuring roundness and straightness with an indicator.
    4. Measure circular runout.
    5. Measure total runout by first measuring the taper, then measuring straightness and runout.
    6. Measure circular and total face runout.

Lesson 5: Flatness and Straightness [ Top ]

After completing this lesson the trainee will be able to:

  1. Identify the following tolerance symbols on part prints:
    1. Flatness
    2. Straightness
  2. Describe the shape and dimensions of these tolerance zones:
    1. Flatness
    2. Straightness of Surface Elements
    3. Straightness of the Axis
  3. State the material condition modifiers which can be applied to the above tolerances.
  4. State whether a particular straightness tolerance applies to the axis or to the surface elements.
  5. Perform the following tasks:
    1. Prepare a part for measuring flatness by leveling the toleranced surface.
    2. Measure flatness with an indicator.
    3. Measure flatness with a flatness gage.
    4. Check straightness with a functional gage.
    5. Measure straightness with an optical comparator.
    6. Measure the straightness of surface elements with an indicator.
    7. Measure the straightness of an axis by determining the form of the feature, measuring the straightness of the surface elements, then calculating the straightness of the axis.

Lesson 6: Orientation and Profile [ Top ]

After completing this lesson the trainee will be able to:

  1. Identify the following symbols on part prints:
    1. Perpendicularity
    2. Parallelism
    3. Angularity
    4. Profile of a Surface
    5. Profile of a Line
  2. Describe the shape and dimensions of the following tolerance zones:
    1. Perpendicularity
    2. Parallelism
    3. Angularity
    4. Profile of a Surface
    5. Profile of a Line
  3. Describe the following types of profile tolerance zones:
    1. Unilateral
    2. Bilateral
  4. Perform the following tasks:
    1. Check perpendicularity with a functional gage.
    2. Measure perpendicularity with an optical comparator.
    3. Measure perpendicularity with a vertical squareness gage.
    4. Measure parallelism with an indicator.
    5. Measure profile with an optical comparator.