position vs true position - just semantics?
position vs true position - just semantics?
(OP)
Everyone at my work who "knows" GD&T from learning it at their old job refers to position, incorrectly, as true position. I think this misuse of terms happens pretty frequently throughout industry. Is it worth fighting the good fight to try to have the people at my work refer to the terms correctly knowing full well that any time they speak with anyone outside of our organization that other person will most likely be using these terms incorrectly anyways?
I have found that if someone was confusing RAME with UAME and you set them straight on the definitions they would probably thank you for the clarification. But when you tell them the actual definitions of position and true position they tend to dismiss it.
Am I the only stickler for correct usage of terms? To me it is nails on a chalkboard every time I hear position called true position.
Also, how come no one incorrectly refers to profile as true profile? At least be consistent with you incorrect use of terms.
I have found that if someone was confusing RAME with UAME and you set them straight on the definitions they would probably thank you for the clarification. But when you tell them the actual definitions of position and true position they tend to dismiss it.
Am I the only stickler for correct usage of terms? To me it is nails on a chalkboard every time I hear position called true position.
Also, how come no one incorrectly refers to profile as true profile? At least be consistent with you incorrect use of terms.





RE: position vs true position - just semantics?
When teaching a GD&T class, I make a point of this distinction, and try to get everyone to call the tolerance the "position" symbol. But in your everyday job, I wouldn't make an issue out of it.
For those who might really insist on calling it the true position symbol, one strategy you can use is to ask them why they don't call flatness the "true flatness" symbol (or true perpendicularity, or whatever).
One popular textbook used to refer to position as TOP, or "tolerance of position." Not wrong in itself, but I say just stick to the terms used in the standard. I think in the newer editions he's backed off from using that acronym.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: position vs true position - just semantics?
I blame Foster for his 'Geometrics...' books and early, non-standard works like Foster's 1963 Honeywell book "A Treatise on Geometric and Positional Dimensioning and Tolerancing."
Slang is a tough thing to stamp out.
**As in the phrase 'put some GD&T on the drawing.' Such drawings already have dimensions and direct tolerances, so the only thing it could mean is to add feature control frames and maybe datum symbols. Hence FCF == GD&T.
RE: position vs true position - just semantics?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: position vs true position - just semantics?
For example, the International Organization for Standardization is using the short form ISO even though it is not correct abbreviation in any official ISO language.
The story usually associated with that is that the short form ISO is not an acronym, but rather, a word derived from the Greek isos, meaning “equal.”
Now, if you ask 100 people what ISO is, 90 of them are probably unaware about “Greek” origin of the word. Nevertheless the term is universally accepted and understood in 200-something ISO member countries (and they don’t bother to create their own local abbreviations, just call it ISO anywhere from Greece to Russia to China)
Similarly, abbreviation GD&T, even if not defined as a term in latest version of the standard, is universally accepted and understood.
It still used by biggest names in the industry, including, but not limited to (in no particular order):
Alex Krulikowski: http://www.amazon.com/Fundamentals-Geometric-Dimen...
David P. Madsen: http://www.amazon.com/Geometric-Dimensioning-Toler...
James D. Meadows: http://www.amazon.com/Geometric-Dimensioning-Toler...
Bruce A. Wilson: http://www.amazon.com/GD-Application-Interpretatio...
Gene Cogorno: http://www.amazon.com/Geometric-Dimensioning-Toler...
Robert H. Nickolaisen: http://www.amazon.com/Certification-Geometric-Dime...
Georg Henzold: http://www.amazon.com/Geometrical-Dimensioning-Tol...
And many others who I hope will forgive me for not mentioning their names.
It is also interesting to note that J. D. Meadows uses term “Geometric product definition”, and G. Henzold uses “Geometrical properties”, so one may say, GD&T should be generally understood as “Dimensioning and tolerancing of geometrical features”.
I really don’t mean to sound rude, but my personal idea would be: just let it go.
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: position vs true position - just semantics?
On the other hand, I have occasionally experienced serious issues caused by improper use of term 'datum' instead of 'datum feature'. From my experience some people that say 'datum' (when they really mean 'datum feature') tend to incorrectly think that relationships between datum features don't have be controlled on the drawing because by definition these features are perfect to each other. It takes some time to explain them that they are wrong. Not to mention it costs money to fix the drawings missing these extremely important relationships.
Another example along the same lines that I can think of is 'squareness' vs. 'perpendicularity'. Perhaps for English speaking people this is clear/obvious, but I can recall at least a couple situations when a non-English speaking person had a really hard time to figure out what the 'squareness' really is in GD&T vocabulary (pardon me, Dave - in D&T vocabulary
RE: position vs true position - just semantics?
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: position vs true position - just semantics?
RE: position vs true position - just semantics?
Certified Sr. GD&T Professional
RE: position vs true position - just semantics?
RE: position vs true position - just semantics?