Name of ASME Document Governing "Dimensioning" 2

[ModulusCT]

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!!

 

[fsincox]

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!

 

[CheckerHater]

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.

 

[fsincox]

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

 

[drawoh]

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

 

[ewh]

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.

...write them down and take responsibility

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

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.




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

 

[fsincox]

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