Rule #1. In the world of engineering drawing there is an infinite amount of complexity to be detailed. All over the world there are parts and mechanisms that are dreamed up every day and for many of them there is a need for the assurance that a particular design will be flexible enough to work […]

Actual Mating Envelope – The Basics Actual mating envelope is a term that refers to a machined / manufactured part’s feature of size “as is” condition. To define what that means specifically, we need a specific individual part to talk about. The reason for that is when you have a part, or bunch of parts, […]

In today’s installment I want to talk about the language of GD&T and perhaps a little about basic geometry and how shapes fuel our thoughts. Any language, to achieve communication, must somehow capture a physical method, accomplishable by our bodies, to change a thought or imagined image, into a physical presentation of some kind. Put […]

Having received feedback about our GD&T blog, I am writing material responding to requests to go over the basics. I can appreciate a reader’s desire for basics from the standpoint of people who learned the convention over the course of their job’s daily routines of making parts and seeing what works and sometimes what doesn’t. […]

In this blog, we’ll discuss the tendency for many engineers to produce partially defined drawings (PDDs) that contain elements of GD&T but leave off the applicable basic dimensions. Not only that, but they fail to note most of the X-Y dimensions that define the geometry. When is it okay to leave information off drawings? But […]

The GD&T (Geometric Dimensioning & Tolerancing) protocol is rapidly becoming the standard for communicating engineering tolerances and allowable variation for product parts. It’s an elegant but not a simple system. Close to 50% of the GD&T drawings coming across my desk use the system incorrectly in whole or in part. This is not meant to […]