GD&T Essentials 2026: A Complete Beginners Guide

Technical drawings are often incomplete and unclear. Only clear drawings can ensure that the functions of a workpiece are fulfilled and that expensive revisions or reworking are avoided. An important tool for achieving this goal is the so-called "Geometric Dimension and Tolerancing". Geometric Dimension and Tolerancing build the basis for a clear and functional specification of components and assemblies with the help of technical drawings. The geometries of a workpiece or assembly relevant to its function are described with the aid of various tolerances. Geometric Dimension and Tolerancing are part of the standard system, the so-called Geometric Product Specification (ISO GPS).

In this course, you will learn the basics, meaning and advantages of Geometric Dimension and Tolerancing compared to older procedures, such as plus-minus tolerances or tolerance chains. You will learn the rules and symbols of the separate tolerance types, such as form, orientation, location and run-out tolerances, and how to apply them to workpieces. The correct application of theoretically exact dimensions (so-called TEDs) and the specification of functional datums and datum systems will no longer be a problem after the course. This course also covers the use of various features of size and dimensional elements. You will also learn how to replace old-fashioned distances and plus-minus tolerances with the new general tolerance according to ISO 22081