GD&T Articles

GD&T Answer video about using a curved profile surface as a datum for 4 holes that are required to remain normal to the curved surface. How do we do this with GD&T profile and position and what do we use as datums? We talk about a lot of very advanced concepts here so make sure…

This is one of our new entries in our GD&T Video Question Line – where we take our student questions from our Engineering Drawing Basics, GD&T Fundamentals, or GD&T Advanced Course (https://www.gdandtbasics.com/gdt-training) and give a detailed response. This question aims to answer how Runout is used to control the form/shape/circularity/cylindricity on a cylinder. It also…

This is a discussion question we received in our Engineering Drawings Basics Course – https://www.gdandtbasics.com/gdt-trai…. Questions about using centerlines are so common that we wanted to post some information about why they are used, and how they impact more than just your hole to hole dimensions.

This is a discussion question we received in our Engineering Drawings Basics Course – https://www.gdandtbasics.com/gdt-training/engineering-drawing-basics/ We get a lot of questions about the projection angle symbols and about the differences between First Angle Projection and Third Angle Projection. In this video, we use animations from our course to illustrate the differences between the two along…

Datums can be confusing. What are they for and how do they restrict our part? In GD&T, Datums are probably the most asked about concept – especially from an inspection point of view. In this video, we discuss how datums actually work and how they are used to control the degrees of freedom on our…

Check out this question brought up about Flatness in our GD&T Fundamentals Course. We get a lot of questions about when flatness can be applied and how datums can be used with this. There are some simple rules in the geometric dimensioning & tolerancing standards about applying flatness to datum features that you can follow,…