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Name of ASME Document Governing "Dimensioning"
2

Name of ASME Document Governing "Dimensioning"

Name of ASME Document Governing "Dimensioning"

(OP)
I am constantly told by people I work with, who are quick to ponit out how much more experience than me they have, that ASME Y14.5-2009 is Geometric dimensioning AND TOLERANCING and not a document about how to be a drafter. I can sort of understand where they're coming from, but am of the opinion that they're totally wrong.

First of all, the document itself says that it supersedes all other specs cited within it, which includes the specs that supposedly govern 'drafting practices'. Seconly, I still haven't found any other document that explains that an angle must start from it's axis of rotation (this is what my checker tells me - this is a plastic, injection molded part), or that a dimension should always have the arrows inside when possible or that two adjacent dimensions should be offset, and not ever share an arrow.

Can anyone tell me which spec covers these things? Because in the past I've always relies on 14.5 and the examples within... Now I'm being told that it's insufficient and that only having knowledge of the 'old way' of drafting is going to be beneficial... or some garbage like that.

Anyway, which ASME spec tells you how to draft? I always thought it was a bunch of theory

Thanks!

I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE plants!!

RE: Name of ASME Document Governing "Dimensioning"

Y14.5 covers dimensioning as well as toleranceing, but not in the depth you are seeking. Supplement the standard by studying some Drafting text books for more insight as to what is being expected of you. The directions that you have been given are not "totally wrong" but are generally accepted good practice (though I disagree with offsetting adjacent dimensions). Ideally, these preferences would be documented in a Drafting Room Manual, but are more frequently tribal knowledge. Don't just look at the information being included on a drawing, but also look at how that info is being presented. The goal is to make the drawing complete, concise, easy to read and subject to only one interpretation.
Considering "knowledge of the 'old way' of drafting" as garbage is unfortunate.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

RE: Name of ASME Document Governing "Dimensioning"

(OP)
None of those specs, except 14.5-2009 actually describes how to dimension a part and what kind of dimensions are acceptable and in what manner they should be placed. According to some people here where I work though, 14.5 is a GD&T manual and not a drafting manual... Which spec in that list shows me how to create a an angular dimension from it's axis of rotation to its second reference?

Any idea what I'm talking about here?

I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE plants!!

RE: Name of ASME Document Governing "Dimensioning"

It's probably time for your company to produce, adopt, or update, its own drafting standards manual to supplement or customize what the ASME document says.

Mike Halloran
Pembroke Pines, FL, USA

RE: Name of ASME Document Governing "Dimensioning"

People who rely on "knowledge of the 'old way' of drafting" are scared of standards because they render their "tribal knowledge" (and themselves) useless.
Ask your "checker" to produce actual document that he is following and listen to the sound of crickets.

RE: Name of ASME Document Governing "Dimensioning"

Agreed CH. This is why I always get into trouble asking to see the documentation from the checkers. That said, there is a lot that is considered "old school" drafting that should be documented (in a DRM or other company standards). Makes for better drawings. You can have very poor drawings that don't violate the standards in any way, but are a bear to read, which is an opportunity for mis-interpretation and mistakes.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

RE: Name of ASME Document Governing "Dimensioning"

ASME Y14.5 is not for learning to do drafting, only GD&T.
Check out MIL-STD-100.

Chris
SolidWorks 13
ctopher's home
SolidWorks Legion

RE: Name of ASME Document Governing "Dimensioning"

MIL-STD-100 has been cancelled, replaced by ASME Y14.100. For dimensioning, you get referred back to Y14.5.
I don't remember MIL-STD-100 being any more detailed as far as dimensioning, but I may be mistaken.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

RE: Name of ASME Document Governing "Dimensioning"

There is no way they are 'TOTALLY WRONG' when they say 14.5 is not a document about how to be a drafter. It lists certain requirements a drawing should meet with regard to dimensioning and tolerancing and more but it's not 'how to be a drafter'.

However, if they do have additional requirements for drafting beyond what section 1 of Y14.5 and the little bits related docs give then they should have some kind of specification to reference - even if it's a fairly informal list or a preferred drafting book or something.

When I was checking I tried to be careful not to arbitrarily impose my preferences, and certainly not to hold up drawings or make a lot of extra work to do so. When it came to things that would stop me approving a drawing I tried to stick to the relevant Y14 series docs and to the things our DRM clarifies plus of course the universal get out of making sure it's a generally clear and easy to understand drawing.

However, I would sometimes suggest what I considered good practices to be used on future drawings.

I think some of the limitations of 14.5 may be a result of it effectively being a consensus document, so some stuff not easily agreed on by those drafting & editing it probably tended to get left out rather than resolved.

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: Name of ASME Document Governing "Dimensioning"

Thanks ewh,
I knew there was a replacement, but didn't go far enough to look it up.
I think the MIL std may be a free download somewhere to use as a start.

Chris
SolidWorks 13
ctopher's home
SolidWorks Legion

RE: Name of ASME Document Governing "Dimensioning"

(OP)
Perfect answer CH... I will ask.

I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE plants!!

RE: Name of ASME Document Governing "Dimensioning"

(OP)
Well apparently, what OH said is absolutely true. Fully defining the part can be done a number of ways, and there may be a better way from time to time, but most of the time, here where I work, the checker just determines what is right and what is wrong... not based on some document she follows. Just based on what she learned during the many years she spent in the aviation industry. That's fine, but when I'm told that if I don't understand why she needs me to take a dimension from one spot as opposed to another, that I need to take a drafting class, I can't help but be a little irritated.

I think a good checker has to be a good teacher as well. Or at least, not a completely coarse and offensive person. The boss says that she's 'good' at what she does because she doesn't back down from what she believes... If that's the only virtue to being a checker, than I need to go back to school and get out of drafting. I've read 14.5 a number of times so that I feel I know how a good drawing is put together (along with 12+ years of experience)... If that's all thrown out the window based on some tribal knowledge than a lot of that work was wasted time apparently.

I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE plants!!

RE: Name of ASME Document Governing "Dimensioning"

ModulusCT,

The title of my copy of ASME Y14.5-2009 is "Dimensioning and Tolerancing". This thing is a standard, and it explains what all those dimensioning and tolerancing symbols and notations mean. Given this standard, or any other standard for that matter, it means that everyone is speaking the same language.

GD&T is a subset of dimensioning and tolerancing.

--
JHG

RE: Name of ASME Document Governing "Dimensioning"

To be well understood, it isn't just what "words" you use in a language that are important but also how you structure your "sentencences". Y14.5 is more of a dictionary than a style manual.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

RE: Name of ASME Document Governing "Dimensioning"

No, I think Y14.5 is pretty good at covering grammar and syntax too, not just the "words," as a dictionary does.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

RE: Name of ASME Document Governing "Dimensioning"

Thesaurus, maybe, but it lacks much in the way of creating a good drawing that a good DRM would cover, such as readability (optimized placement of dimensions).

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

RE: Name of ASME Document Governing "Dimensioning"

Modulus,

Is there a specific drafting technique that is in question? If so, why don't you tell us what the conflict is and we can add our input in order to further complicate things...dazed

John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

RE: Name of ASME Document Governing "Dimensioning"

I personally wouldn't take any drafting manual as gospel. After my interactions with the writers with Drafting Zone, I've discovered that their vetting process leaves a lot to be desired. In general, there are people with opinions on how things should be, but very little in the way of official statements from any agency. Bottom line, as long as you are communicating the requirements in an unambiguous manner, the drawing is suitable.

Matt Lorono, CSWP
Product Definition Specialist, DS SolidWorks Corp
Personal sites:
Lorono's SolidWorks Resources & SolidWorks Legion

RE: Name of ASME Document Governing "Dimensioning"

My quote from another thread:
"What you, and many others want, is the standard to say there is only "one way". My impression is the standard is intended to give multiple ways of solving a problem so people can find the one that is right for their particular application."
I agree with CH, what people really is something that says their way is right.
If you read the preface to the Y14.5M-2009 standard it basically says: "the old way of dimensioning was not good enough". Not many want to here that!
Frank
PS
Thanks to my friends here, I know that now ISO 14495 says it too!

RE: Name of ASME Document Governing "Dimensioning"

Actually I am not a proponent of “chiseled in stone” rules.
Add a note to the drawing. Create an amendment. Let it be “your rules”. But write them down and take responsibility.
Otherwise it’s like police pulling you over for running imaginary stop sign.
“The sign is where I think it is” – even the most law-abiding citizens will not keep up with that.

RE: Name of ASME Document Governing "Dimensioning"

As the thread on a simple plate with holes shows: different people have different methods, I am not opposed to you doing it the "old way" or using composite tolerances, just don't tell me there is only "one right way"!
Frank

RE: Name of ASME Document Governing "Dimensioning"

Quote (ewh)


To be well understood, it isn't just what "words" you use in a language that are important but also how you structure your "sentencences". Y14.5 is more of a dictionary than a style manual.

I didn't say "speaking it well."

There is all sorts of good drafting practise that is outside the scope of ASME Y14.5. Given the standard, there generally are multiple ways of doing everything, and multiple requirements.

--
JHG

RE: Name of ASME Document Governing "Dimensioning"

Quote (fcsuper)

as long as you are communicating the requirements in an unambiguous manner, the drawing is suitable

Yes; DRM's are written to remove some of that ambiguity. No DRM is going to be perfect. Their purpose is to tailor drafting practices to meet the needs of that organization.

Quote (CheckerHater)

...write them down and take responsibility

I agree. Exceptions should be allowed based on the situation, but enforced rules should be documented.

Quote (drawoh)

Given the standard, there generally are multiple ways of doing everything

I agree for the most part. The OP is asking about documentation of preferential practices. I have not found any mention in the standard of an angle having to start from its axis of rotation, and his checker's preference that two adjacent dimensions should be offset, and not ever share an arrow actually goes against the standard. These are the sort of practices that beg to be documented in a supplemental company DRM, as relying only on a checker's undocumented preferences can not be sustained. No one is perfect and no one lives forever.

One area in the standards that seems to be lacking is in Y14.3 MULTIVIEW AND SECTIONAL VIEW DRAWINGS... is an orthographic projected view from a section (full, half or partial) view allowed? The standard addresses taking a section from a section, but that's about it. I am struggling to find support in the standard for prohiting such views as this goes against what I was taught, but this practice is very common where I work (the "DRM" already takes exception to the section-from-section rule). I feel I am going to lose this argument without a documented source for prohiting this practice.

peace

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV

RE: Name of ASME Document Governing "Dimensioning"

These are the kind of "old drafting practices" that have also been changed by the CAD world, when is the last time you saw a revolved section view that DID NOT section the ribs or impeller blade, etc? It is not just dimensioning practices that have been changed to accommodate!
Frank

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