GD & T - A Brief Summary

GD & T - A Brief Summary

Geometric Dimensioning and Tolerancing (GD&T) is a system for defining and communicating engineering tolerances. It uses a symbolic language on engineering drawings and computer-generated three-dimensional solid models that explicitly describes nominal geometry and its allowable variation.

 If it is a geometrical aspect of a feature rather than its size that is crucial to its function, sometimes features that are not within dimensional limits can still be functional. This realisation is said to have marked the beginning of GD&T.

There is a lot to learn when it comes to mastering GD&T, so this post will serve as a launching point to help you understand the most important GD&T concepts, including:

o Computer Numberial Control (CNC) machining tolerances

o The Datum Reference Frame (DRF)

o Interpreting GD&T Symbols

o The Feature Control Frame

o Communicating Basic Dimensions

o Material Condition Modifiers

References:

GD&T 101: An Introduction to Geometric Dimensioning and Tolerancing -- https://www.fictiv.com/hwg/fabricate/gdt-101-an-introduction-to-geometric-dimensioning-and-tolerancing

GD&T Basics -- https://www.gdandtbasics.com/gdt-symbols/

GD&T Video -- https://www.youtube.com/watch?reload=9&v=gHoRlBgfsRw

GD&T Video -- https://www.youtube.com/watch?v=-V3j3XvSZuA

GD&T Basics – An Introduction -- https://www.sigmetrix.com/case-studies-2/gdt-case-studies-and-whitepapers/gdt-basics/