Definition of Terms- Maximum Material Condition

By Chris A. Lindenberger

With the previous topic, Rule #1, we discussed the need for a guiding principle to govern the need for geometry to follow rules that allow things to fit under all conditions, given that the proper engineering has been established for the condition being considered. That principal was stated as “size controls form.” In it the […]

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Definition of Terms-Feature Control Frames

By Chris A. Lindenberger

Today our featured GD&T term is “feature control frames.” We at Metalcraft decided some time ago to put together a glossary of sorts. It will be alphabetized in proper fashion but as various terms are added they will not be added in A to Z fashion, but more in order of importance, or more importantly, […]

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Definition of Terms-Rule #1

By Chris A. Lindenberger

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 […]

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Definition of terms- Actual Mating Envelope / Related and Unrelated.

By Chris A. Lindenberger

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, […]

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The Language of GD&T

By Chris A. Lindenberger

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 […]

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GD&T Fundamentals

By Chris A. Lindenberger

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. […]

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Partially Defined Drawings: Adapting to the World of CAD-Based, Geometry-Defined Working Drawings.

By Chris A. Lindenberger

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.    CAD models don’t have tolerances and they don’t have […]

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Implications of the GD&T System for Communicating Tolerances

By Chris A. Lindenberger

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 […]

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