Known as the "Doctor of Dimensioning," Alex Krulikowski is a noted educator, author, and expert on Geometric Dimensioning and Tolerancing (GD&T). He has more than 30 years of industrial experience putting GD&T to practical use on the shop floor.
Alex has taught GD&T to tens of thousands through his workshops and seminars, and to countless others through his books, self-study courses, videos, and computer-based training programs.
ETI offers convenient public workshops on a variety of GD&T-related topics.
ETI Public Workshops
offers a series of workshops in Livonia, Michigan.
Take a look at our upcoming workshops.
Fundamentals of GD&T 2009
ISO Geometrical Tolerancing
Intro to Statistical Stacks
Fundamentals 1994 for Inspectors
Engineering Drawing Requirements
ASME Y14.5 1994-2009 Standard Update
Solid Model Tolerancing (Y14.41)
To learn more about these public workshops, click
To register for a workshop, click here.
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ETImail is a regular online publication devoted to geometric dimensioning & tolerancing. Each edition features a host of GD&T resources and links, as well as dimensioning tips by noted GD&T author and ETI founder, Alex Krulikowski.
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How Similar are the Y14.5 1994 and 2009 Standards?
The changes between the 1994 and 2009 versions of the standard are many and have a major impact on drawing interpretation. This is part one of a three-part article.
A fallacy about differences between the 1994 and 2009 Y14.5 standards
In preparing for my upcoming workshop on Y14.5-2009, I was musing about one of the common fallacies regarding the 2009 version of the Y14.5 standard. There is a misperception that the 2009 version of the standard contains only a few minor changes from the 1994 version.
In my travels, I have found that a number of engineers, managers, pundits, and trainers believe this fallacy. I have even heard a few of these misguided souls say, “If you know the 1994 standard, you can just change the standard reference in the title block of the drawing and start using the new standard.”
Keep in mind that an engineering drawing is a legal document, so this practice would be dangerous. It could result in changing the interpretation of some of the GD&T specifications or even having some specifications become illegal.
This article will explain several examples of the differences between the 1994 and 2009 versions of the standard and how they can have a major impact on drawing interpretation. First, let’s look at some reasons why the skeptics believe the two versions of the standard are very much the same.
Why some try to minimize the differences between the 1994 and 2009 standards
Why would anyone want to minimize the differences in the standards if they are significant? There is no way to really know, so I will speculate by classifying the skeptics into two categories: those who may intentionally want to convince others that the changes are minimal and those who unwittingly believe the fallacy.
Some trainers may feel it is easier to sell their 2009 training if customers think the new standard is only a minor change of the 1994 standard. By suggesting that the changes are minor, they may convince potential clients to purchase 2009 training and move their company to the 2009 standard. Other skeptics may be GD&T experts who work in companies. They want to move their organization to the 2009 standard but may not be confident that they can convince management to make the change. For this reason, they gloss over the subtle (but numerous and significant) changes and try to sell the adoption based on the fact that it will be easy to update the company.
There are much stronger reasons to adopt the 2009 standard. Adoption of the 2009 standard should be based on its new features and benefits, not on how minimally it will impact your organization.
Now for a few words about the innocent skeptics who unknowingly believe the changes are minimal. This group is made up of a variety of people, but one common trait they share is that they are often not fluent in GD&T. They may get their misperceptions from one of the groups above or from looking at (but not studying) the Y14.5 standard. The standard itself does not do a good job of listing the revisions in the 2009 edition, so some people may be misled by the description in the standard’s foreword and appendix.
If they have not thoroughly read the new standard, they don’t really know what the changes are. Since the standards appear to be similar, they believe the 2009 version of the standard only contains minor differences.
Differences between 1994 and 2009 Y14.5 standards
How different are these two standards? On the surface they appear to be very similar. There are a number of minor changes like reorganized sections. However, there are also many significant changes. A brief overview of the changes is shown in the chart below.
Click for a larger view or download a printable 8.5x14 PDF
As you can see, there are significant additions and revisions in the new standard, and the impact of these changes ranges from having multiple interpretations to not having any clear interpretation. If you do not fully understand these changes, you, or your employees, suppliers, etc., will be guessing at the interpretation of drawing specifications.
If you would like to gain an in depth understanding of the 2009 Y14.5 standard, consider attending my upcoming workshop. See the link to the April 15th workshop in the side bar of this newsletter.
It is impossible to put a number (percent) on how much of the Y14.5 standard is new or revised. Simply put, the two versions look similar to the untrained eye, but contain major differences that have a significant impact on drawing interpretation.
Do you agree or disagree? I’d like to hear your opinion.
One thought that I would like to leave you with is the fact that, because drawings are legal documents, safety and costs are associated with the preciseness of the specifications and their interpretation on the drawing. For that reason, I believe it is critical for every drawing user to understand the symbols based on the standards referenced on the drawing.
A number of major companies have already adopted the 2009 standard for new designs. These designs are starting to be released to suppliers. If you try to use your knowledge from the 1994 standards to interpret drawings made to the 2009 standards, you will make mistakes - and those mistakes may cost far more than it would to learn the new standard.
This reminds of a quote by James Bryce:
“Three fourths of the mistakes a man makes are made
because he does not really know something he thinks he knows.”
The 2009 Y14.5 standard has many new features that make it worthwhile and profitable to adopt. In the next issue of ETImail, I will explore some of the major benefits of adopting the ASME Y14.5-2009 Standard.
|We welcome your feedback. Send comments about this article to ETImail. Your opinions may be posted in the next issue.
This article may be reprinted free for use by your organization if our Reprint Policy is followed.
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ETI continues to add new GD&T products and services in order to provide you with more GD&T training options. Keep an eye on this section to read about our latest news. This issue: ETI offers many of our workshops in the Detroit-area. Visit us at our Livonia. Michigan headquarters.
Public Workshop Calendar for 2013
Workshops by subject
Workshop info in pdf format
|GD&T Advanced Concepts
| ASME Y14.5 1994-2009 Update
|Engineering Drawing Req's
|Fundamentals of GD&T - 1994
|Fundamentals of GD&T - 2009
|Fundamentals for Inspectors
|ISO Geometrical Tolerancing
|Solid Model Tolerancing
ETI offers a series of training events in the Detroit area. All of the courses were developed by GD&T expert and ETI president, Alex Krulikowski. We are now offering three new courses:
Fundamentals of GD&T: ASME Y14.5-2009 - 2-Day Workshop
If you have a basic understanding of mechanical drawings, we can teach you the terms, rules, symbols, and concepts of GD&T as prescribed in the ASME Y14.5-2009 Standard. This 2-day workshop provides an in-depth explanation of geometric symbols, including each symbol’s requirements, tolerance zones, and limitations. The class includes a comparison of GD&T to coordinate tolerancing; an explanation of tolerance zones; Rules #1 and #2; form and orientation controls; tolerance of position; runout and profile control. Read more about the course.
Fundamentals of GD&T for Inspectors - 2-Day Workshop
This 2-day workshop includes an introduction to geometric dimensioning and tolerancing and how to inspect GD&T requirements. The course is based on ASME Y14.5M-1994, Y14.5.1 and Y14.43 standards. Read more about the course.
ISO Geometrical Tolerancing - 2-Day Workshop
Enable global sourcing for your company and learn to read drawings created in other countries. The ISO Geometrical Tolerancing workshop will teach you the ins and outs of utilizing the ISO standards. The 2-day course will give you a fundamental knowledge of ISO 1101:2004 and related standards and their application on drawings. Read more about this course.
See the complete public workshop by subject. See our location in Livonia, Michigan.
ETI's public workshops are complete courses that teach how to apply and interpret GD&T on the job. They are more in depth than most public seminars, and much more than simply lectures. Each workshop provides hands-on training that includes practice exercises to help reinforce concepts. When you register for any ETI workshop, you know you'll be receiving the most thorough GD&T training available.
Don't have time to travel? ETI can bring the workshops to your site. To learn more about our onsite workshops, call 734-744-5940 or click here for more information.
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