Drawings as legal documents

[edmario4]

I'm doing research on the use of drawings as evidence in court. I would appreciate any information about such use in any engineering specialty. I'm especially interested in situations in which drawing errors or substandard drawings were an important factor in a legal decision.

Thank you very much fo your help.

 

[PeterStock]

If there is no standard referenced, the standard that would be used is the one where the person creating the drawing looses.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net

 

[MechNorth]

Basically, Peter has the right idea. In the absence of a documented standard, any reasonable interpretation as determined by a skilled practitioner (i.e. expert witness / sme) will be the basis of the decision.

Dates on a drawing mean nothing, or more correctly almost nothing, as far as basis for interpreting the drawing. Without invoking a specific standard & revision level, would you interpret concentricity by the ASME '82, '94, '09 or maybe one of the ISO releases, or CSA, or DIN, or JSA, or MilSpec? Or maybe by your high school math definition of concentricity? Without invoking a GD&T standard, there's no means (that I'm aware of) for referencing to datums, and no definition of what parallelism means in that particular context. Basically, invoking a specific standard establishes the "Rosetta Stone" for interpreting that drawing. Without it, it's like a Na'vi trying to speak Klingon without the benefit of Wikipedia or Google Translate.

Jim Sykes, P.Eng, GDTP-S
Profile Services

http://www.profileservices.ca

TecEase, Inc.

http://www.tec-ease.com

 

[drawoh]

If there is no standard referenced, the standard that would be used is the one where the person creating the drawing looses.

Is that the law, or your opinion?

It appears that most people sitting in front of CAD stations do not understand GD&T, and make no effort to think out their tolerancing. A witness, expert in the standards, is not really an expert in what such a drafter was trying to say.

JHG

 

[ewh]

But if what the drafter was trying to say does not agree with the standard noted on the drawing, he loses. I would think that the other approving signatories would stand to lose more, however.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[PeterStock]

"Quote (PeterStock):
If there is no standard referenced, the standard that would be used is the one where the person creating the drawing looses."

I was making the point that if your in court and the interpretation of your drawing is in question, it would be up to you to show that the other party is in error. If there is no standard in place, the standard would be the practice of the other party not yours. This is just my opinion, but I think it is reasonable.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net

 

[fsincox]

edmario4,
I really owe you an apology for hijacking this thread. I believe business people weigh the risks, business itself is described as taking a risk, a gamble. If I am to “judge by the fruits”, as I was taught, I would have to say that outside of government and big businesses most companies are not really swayed by the “legal” fear factor all that much. "It just will not happen to me or if it does we can absorb it". This may be a legitimate position to take. I think from all the conversations here about poor drawings it should be obvious to all. In another forum there is a gentleman, Walt, who noted something like “businesses are exist to make money”, I was shocked at first, I though what does this have to do with good GD&T. Then, I believe, I realized what he was getting at.
Until GD&T just makes the job easier, faster, better not more complicated it will be avoided. There are some here that advocate not using it for the same reason. I have areas myself where I find it hard to justify from a buisness point of view, although not a legal one.
Frank

 

[fcsuper]

There's a lot of myths about GD&T that 90% of the engineers believe in. Here's a list that I had to stave off just the other day when I helped another engineer to clean up his drawing:

-GD&T is not needed

[GD&T is usually more representative of design intent with cleaner drawings.]

-GD&T costs more or "I've been doing this for XX years and I've always seen GD&T raise the cost"

[For some reason, it seems there are a lot of people that think the CNC machines are magically less efficient when making a part from a drawing that has GD&T, even when tolerance zones for pos tols are bigger and the set up is exactly the same.]

-GD&T requires someone to know how to measure it

[Depending on how it is employed, GD&T allows for more methodology for inspection. Vision systems or optical comparators do the same job on measuring holes regardless. ...and no one had better be using calipers to find the center of a hole anyway!]

-GD&T requires the vendor to do more work

[See previous responses]

-GD&T over-constrains the part

[Only if someone applies it incorrectly, which can happen with linear dimensions too. GD&T can reduce constraints by allowing for more variation within the design intent.]

Anyone where any others recently?




Matt Lorono
Lorono's SolidWorks Resources & SolidWorks Legion

http://groups.yahoo.com/group/solidworks & http://twitter.com/fcsuper

 

[KENAT]

I posted a whole thread about it some time back, maybe in 2006 or 2007.

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