Skip to main content

Category: GD&T & Print Reading Basics

Articles related to reading engineering drawings and interpreting GD&T on the prints

Restrained Condition Note

by Jason Richter on June 9, 2022.

Some parts, such as those made of rubber or sheet metal, may fail inspection due to deformation from gravity if left in their "free state." This can be prevented by invoking a "restrained state."

Position Tolerance vs “True Position”

by Crystal Bemis on June 8, 2022.

Though many people refer to the GD&T Position symbol as "True Position," they are not the same thing. Read on to learn the difference between Position and True Position and how they work together to define the position of a feature.

Why Use GD&T?

by Crystal Bemis on April 27, 2022. (sticky)

We get a lot of questions from students asking why they would want to use Geometric Dimensioning and Tolerancing (GD&T) over coordinate dimensions. Some believe that using GD&T will result in tighter tolerances and increase a part’s cost. Others believe...

The Datum Reference Frame

by Crystal Bemis on April 4, 2022.

What is a Datum Reference Frame? Datums are used in GD&T drawings to create a reference system for inspecting a manufactured part. This reference system is called a Datum Reference Frame (DRF). Datums are derived from datum features. Datum features...

Take our GD&T Skills Assessment Quiz!

by Crystal Bemis on January 28, 2022.

Having a good understanding of Geometric Dimensioning and Tolerancing is very important for anyone working in a mechanical field. GD&T is the language used in design, manufacturing, and quality inspection to communicate on engineering prints. It combines a set of...

How to Use the Drill Tap Wall Chart

by Crystal Bemis on November 5, 2021.

The most common way to produce an internal thread is to drill a hole and then use a tap to produce the thread. This is usually referred to as a tapping drill for the size of the thread that needs...