Instructor: James Thornburgh Unit 1 GD&T Instructor: James Thornburgh Agenda: Objectives What is GDT? Why it’s Important Measuring Break

Objectives Identify and draw GD&T Symbols Correctly use GD&T symbols Describe Maximum and Minimum material conditions Describe and correctly apply Datums Identify various inspection tools Demonstrate 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 important Are 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 Devices Help you to determine if a part is to spec. Open You measure the piece by it’s self Functional You put the piece in a fixture to determine if it’s good Go, No-Go Gauges

Calipers Vernier Dial Digital

Reading Vernier Caliper

Reading Vernier Caliper

Micrometers Vernier Digital

Reading Vernier Micrometer

Surface Plate

Height Gauge

Dial Indicator

CMM

Material Conditions MMC LMC Maximum Material Condition When a Feature Weighs the Most Small Hole, Large Object LMC Least Material Condition When a Feature Weighs the Least Large Hole, Small Object

Material Conditions RFS Material size doesn't matter for Tolerance

GD&T Symbols

Control Types Form Controls Orientation Controls Location Controls

Form Controls Straightness Flatness Circularity Cylindricity

Form Controls

Flatness Microscopic View of surface

Flatness

Orientation Controls Parallelism Perpendicularity Angularity Profile

Orientation Controls

Angularity

Profile

Location Controls Position Concentricity Runout

Position What is the shape of a normal Tolerance Zone? 2.00±.02 . 02 2.00±.02 .75±.02

Position What is the Max it can be out of position? . 02 . 03

Position The Position Tolerance sets a round Tolerance Zone Use Basic Dimensions that have Zero Tolerance Symbolized by drawing a Rectangle around Dim

Position 2.00 .75 Ø2.00 Ø.02

Runout

Defining Datums

Defining Datums

Feature Control Frame Houses GD&T Symbols

Datums for Plane

Datums for Axis & Centerline

What do They all Mean?

What do They all Mean? Datum B Feature 11.9 12 38.6 0.4 0.5 38.5 0.6   Datum B Feature 11.9 12 38.6 0.4 0.5 38.5 0.6 38.4 0.7 38.3 0.8 38.2 0.9 38.1 1.0 38.0 1.1

Lab Assignments & Homework Measuring Handout Workbook 16.1-16.3 Homework Read Ch 16 Do Review Questions 1-10