Instructor:James ThornburghUnit 1GD&TAgenda:ObjectivesWhat is GDT?Why its ImportantMeasuring Break

ObjectivesIdentify and draw GD&T SymbolsCorrectly use GD&T symbols Describe Maximum and Minimum material conditionsDescribe and correctly apply DatumsIdentify various inspection toolsDemonstrate the use of measuring devices.

What is GD&T?GD&T is a way of dimensioning that takes into account function and fit with related parts.

Why GD&T is importantAre Parts Made exactly to the drawings?GD&T allow drawing to be more accurately dimensioned, with looser tolerances.

Why GD&T is important

Measuring & Inspection DevicesHelp you to determine if a part is to spec.OpenYou measure the piece by its selfFunctionalYou put the piece in a fixture to determine if its goodGo, No-Go Gauges

CalipersVernier

Dial

Digital

Reading Vernier Caliper

Reading Vernier Caliper

MicrometersVernier

Digital

Reading Vernier Micrometer

Surface Plate

Height Gauge

Dial Indicator

CMM

Material ConditionsMMCMaximum Material ConditionWhen a Feature Weighs the MostSmall Hole, Large ObjectLMCLeast Material ConditionWhen a Feature Weighs the LeastLarge Hole, Small Object

Material ConditionsRFSMaterial size doesn't matter for Tolerance

GD&T Symbols

Control TypesForm Controls Orientation ControlsLocation Controls

Form ControlsStraightnessFlatness CircularityCylindricity

Form Controls

FlatnessMicroscopic View of surface

Flatness

Orientation ControlsParallelismPerpendicularityAngularityProfile

Orientation Controls

Angularity

Profile

Location ControlsPositionConcentricityRunout

PositionWhat is the shape of a normal Tolerance Zone?

PositionWhat is the Max it can be out of position?

PositionThe Position Tolerance sets a round Tolerance ZoneUse Basic Dimensions that have Zero ToleranceSymbolized by drawing a Rectangle around Dim

Position

Runout

Defining Datums

Defining Datums

Feature Control FrameHouses GD&T Symbols

Datums for Plane

Datums for Axis & Centerline

What do They all Mean?

What do They all Mean?

Datum B Feature11.91238.60.40.538.50.50.638.40.60.738.30.70.838.20.80.938.10.91.038.01.01.1

Lab Assignments & HomeworkLabMeasuring HandoutWorkbook 16.1-16.3HomeworkRead Ch 16Do Review Questions 1-10