Everything I needed to know about GD&T I learned from my dog
or
GD&T for Dummies
This free online textbook makes GD&T fun and easily understandable. I used illustrations involving dogs to keep it entertaining and because I am a dog lover. I think you will find that GD&T is easy if presented properly. Have fun!!!
This textbook is based on the ASME Y14.5 2009 standard.
An expanded version of this book, including 336 exercises with solutions, is available for sale in pdf format. Click here to go to the ebook for sale
Ebook showing the significant updates in the 2018 standard vs. the 2009 standard
Video about when to use RFS, MMC, LMC
Video about Pattern Datums
Video about Unequally Disposed Profile
Video about LMC and LMB
Video about Net Hole and Slot
Table of Contents
Some Philosophy
Dimensioning for Function
Rules, Standards, Definitions
ASME or ISO standard
Standard Notes
Where GD&T does not apply
Unequal Bilateral Size Tolerances
Feature Control Frame
Basic Dimensions
Features of Size
MMC, LMC, RFS
Rule #1
Actual Mating Envelope
Free State Modifier
Simultaneous Requirements
Modifiers - Concise Definitions
Maximum Material Condition
Maximum Material Boundary
Least Material Condition
Least Material Boundary
Datum Translation Symbol
Maximum Material Boundary Datum Simulator
Basic Boundary Datum Simulator
Tangent Plane Modifier
Unequally Disposed
Non Uniform Profile
Projected Tolerance Zone
Statistical Tolerance
Free State Modifier
Independency Symbol
Continuous Feature
Between
All Around
All Over
Boundary
Each Element
Each Radial Element
Datums
Datums introduction
Degrees of Freedom
Planar Datums
Feature of Size Datums
Datum Targets
Advanced topic - Customized Datum Reference Frames
Form tolerances
Flatness
Applied to a surface
Applied to a center plane
Straightness
Applied to a surface
Applied to an axis
Circularity
Cylindricity
Orientation tolerances
Perpendicularity
Applied to a surface
Applied to a feature of size RFS
Applied to a feature of size MMC
Parallelism
Angularity
Location tolerances
Tolerance of Position
Rules
Tolerance of Position RFS
Projected Tolerance Zone
Composite and multiple single segment Tolerance
Bonus Tolerance Introduction
Tolerance of Position MMC
Calculating whether or not a hole is in spec with bonus tolerance
Datum Feature Shift Introduction
Tolerance of Position MMC and MMB
Zero Tolerancing at MMC
Tolerance of Position at LMC and LMB
Six different datums derived from one datum feature
How Tolerance Of Position controls Perpendicularity
When to use RFS, MMC, and LMC
Datum Feature Shift relative to a pattern of holes
Boundaries used with Tolerance of Position
Locating datum features to a dash datum derived from those features
CMM and CAD working together for pattern datums & datum targets
Advanced Topic (calculations) - Are holes in spec with bonus and shift
Concentricity
Symmetry
Profile tolerances
Controlling Form
Controlling size with coordinate tolerance
Controlling size with profile tolerance
All around
All over
Unequally disposed
Controlling orientation
Multiple Single Segment and Composite profile
Composite profile for planar surfaces
Profile of a line
Profile with datum feature shift
Runout
Some Practical Examples
Dimensioning Features of Size - buttons on a key pad
Dimensioning Symmetrical Widths
Dimensioning Pipes
Classic datum scheme for a cover
Multiple datum reference frames on a part
Pattern Datums
Dimensioning the outside edges of a part
Dimensioning slots that have draft (including how to locate)
Tolerances between multiple DRFs with a single manufacturing set-up
