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pass rate for ASME Y14.5 certification test

pass rate for ASME Y14.5 certification test

(OP)
I just read on the Tec Ease web site that the pass rate for the senior level test is only 15%. Does anyone know what the pass rate for the technician level test is? I am planning on taking the 2009 technician level test as soon as it is available (~end of January). If the pass rate for the technician test is anywhere near as low as the senior test I will adjust my studying accordingly.

RE: pass rate for ASME Y14.5 certification test

AndrewTT:

FYI: In 1998 I studied about 1 hour, 4-5 days a week for around a year and passed the Senior Level with a 90's score.

Certified Sr. GD&T Professional

RE: pass rate for ASME Y14.5 certification test

2
I train non-English speaking people to pass GDTP-T exam written in English. Up to this point from out of approximately 80 people trained there was only one person that didn’t pass the exam. In my opiniom that speaks for itself.

Have nothing against Tec-Ease or any other GD&T training company, but if the company offers preparation course for a GDTP certification, it is in its best interest to present it as very difficult to pass without extra assistance.

RE: pass rate for ASME Y14.5 certification test

They are probably reporting the expected rate based on the applicable population, not for those who study. I know 3 people who took the '1994 test; one who had good experience and studied, one a loud mouth who studied, and the third was a loud-mouth know-it-all who didn't need to study. Of them, only the last didn't pass the first time, so that's a 66% pass rate in that tiny sample.

Based on the work of those who haven't studied, I'd say 15% is high, but maybe TecEase finds those who have self-selected.

What is more key is if a lot of the test is 'parrot.' This is the type where phrases are slightly altered from the exact wording of the standard and it is up to the test taker to identify which most accurately parrots the original. 'Parrot' questions require memorization but not much understanding. Taking off points, for example, by not recognizing that a datum cannot be modified; that modifiers only apply to datum features.

I contrast those with 'ferret' questions, where one needs to understand how the rules work to produce results.

'Parrot' questions are popular because they are easy to make into multiple choice questions and true-false questions.

Some are likely to be hard. For example, on http://gdtseminars.com/2010/09/06/sample-senior-le... , question 3 is a question that is not answerable because the relation between the involved datums -ooops- datum features, isn't specified. Answering it requires making an assumption about the relationship between datum feature B and datum feature A.

RE: pass rate for ASME Y14.5 certification test

Dave -- your beef noted and drawing revised. (Added the perpendicularity.)

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

RE: pass rate for ASME Y14.5 certification test

Quote (pmarc)

I train non-English speaking people to pass GDTP-T exam written in English. Up to this point from out of approximately 80 people trained there was only one person that didn’t pass the exam. In my opiniom that speaks for itself.


Well, I think that is because YOU are an excellent teacher. No irony at all. You don't believe me? Look at your own posts here on eng-tips (and how many stars / appreciations you got:)) bigsmile

pmarc,
Let the company make some money (that's why they are in business) from the people who are not autodidacts.

RE: pass rate for ASME Y14.5 certification test

(OP)
I learned a new word. smile

So, if I got all 6 questions from the above link correct (thought they were pretty easy) am I probably good for the technician test?

RE: pass rate for ASME Y14.5 certification test

No guarantees on that, Andrew pipe
It's meant to just give a flavor for the type of questions that might appear.

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

RE: pass rate for ASME Y14.5 certification test

@Belanger about Sample test question 1:

Do we still use definition of "derived median plane" as "imperfect plane"?

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

RE: pass rate for ASME Y14.5 certification test

Oh brother -- now 3DDave has put all of this on center stage...

CH, recall that the certification test is based on the 1994 standard. So paragraph 1.3.15 would say yes. And in 2009, paragraph 1.3.30 also uses the same terminology of "imperfect" plane.

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

RE: pass rate for ASME Y14.5 certification test

Given definition of plane as "theoretically perfect surface" could we add it to our virtual "errata list"?

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

RE: pass rate for ASME Y14.5 certification test

JP - Google helped. I searched for Y14.5 test questions.

The funny/sad result was discussion from a guy who said he had studied the heck out of the '2009 standard, back in 2012 and done really poorly on the ASME test, not realizing that it was based on a nearly 20 year old version.

Makes me believe that if ASME wants to get in the for-profit testing business they need to develop and vet the test among the committee members before the related standard can be issued, so they all hit the market at the same time. Waiting more than a decade is unacceptable. I am also curious if/why they require some proof of industry experience. That makes no sense because it suggests that industry is sufficiently informed to reliably vet the users; if so, there would be no need to certify anyone.

RE: pass rate for ASME Y14.5 certification test

(OP)
I have read people's posts saying they have seen drafts of the new version of Y14.5. I don't understand how you can work on or come out with a new revision to the standard and not have the test available for the last revision yet.

I don't want to get certified to the 1994 standard if it is about to be 2 revisions old. Yet I cannot get certified to the current standard because there is no test available. Here I sit, still waiting.

RE: pass rate for ASME Y14.5 certification test

AndrewTT:

I was at a Y14.5 Committee meeting in Dayton OH in 2010 and "discovered" that members are not compensated by ASME for the time. The entire standards system is (indirectly) financed by companies, gov't entities and other organizations who "use" the standard. In this light consider the effect of a reduced industrial base in the USA. At the 2010 meeting there was a discussion that several active members could no longer attend because they no longer had jobs at the company who was financing there participation. Sad but true. So I assume one reason for the "delay" in updating tests is a lack of adequate participation (membership) to keep all of the sub-committees staffed. Food for thought.

Certified Sr. GD&T Professional

RE: pass rate for ASME Y14.5 certification test

Quote (Belanger)

Oh brother -- now 3DDave has put all of this on center stage...
Apologies in advance, but while we're on the subject...

For sample question #3, I'm getting 16.15 as the answer. Imagine datum feature B is a perfect cylinder of diameter 152.5 everywhere except for a flat spot at the top that results in 151.5 local size. Do you agree?

pylfrm

RE: pass rate for ASME Y14.5 certification test

Maybe -- I'll sketch it out on Monday and see. (Others can chime in too if that sounds right.)

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

RE: pass rate for ASME Y14.5 certification test

Quote (greenimi)

Well, I think that is because YOU are an excellent teacher. No irony at all. You don't believe me? Look at your own posts here on eng-tips (and how many stars / appreciations you got:))

Thank you, but I would not say it is a matter of what kind of a teacher I am - at least not in case of preparation course for GDTP certification. One of the most important things (if not the most important) is that these folks are told they have to study the standard carefully before they go to the exam. The training I do for them is only 10 hours long (1 hour per week), so it is technically impossible to touch in details everything that is required to pass the test. They have to study the book on their own afterward. There is a body of knowledge document available for free on the ASME website (also in form of official Y14.5.2 standard) that is very useful to determine what needs to be studied in particular.

Perhaps I shouldn't, but I always tell them that this test (Technologist level) is not to recognize how good they are in GD&T, but is to check their knowledge of the content of the standard, and that this obviously has some pros and cons. One of the pros is that they may actually have no idea on how to properly apply GD&T on real drawings yet they can become GDTP certificate holders (that is unfortunately one of the biggest flaws of the exam on both levels, in my opinion). One of the cons is that even the most experienced guys that went through hundreds of different real-life applications of GD&T, will most likely have difficulties to pass the exam, because in the test they may find questions about things like minimum allowable distance between dimension line and the part contour, or proper selection of different line styles (chain vs. phantom vs. dashed vs. thick vs. thin, etc.). Who cares about remembering that in reality? One may always open the book and check such details when needed, right?

There is a lot to say about this subject...

Quote (CH)

Do we still use definition of "derived median plane" as "imperfect plane"?

Quote (CH)

Given definition of plane as "theoretically perfect surface" could we add it to our virtual "errata list"?

When the draft of the new version of Y14.5 was released for public review, among many other comments I submitted the very same question to the committee. Since the Derived Median Plane is imperfect, then how is it possible that they call it "plane", which by mathematical nature is perfect? It was in January 2016 - I am still waiting for a reply.

Quote (pylfrm)

For sample question #3, I'm getting 16.15 as the answer. Imagine datum feature B is a perfect cylinder of diameter 152.5 everywhere except for a flat spot at the top that results in 151.5 local size. Do you agree?

Since J-P let others to chime in, I agree with the above. The OD B can be also imagined as a perfect cylinder of diameter 151.5 produced with maximum possible perpendicularity error for that size = 1.0.

RE: pass rate for ASME Y14.5 certification test

I agree the analysis that pmarc made:

Quote (pmarc)

Since J-P let others to chime in, I agree with the above. The OD B can be also imagined as a perfect cylinder of diameter 151.5 produced with maximum possible perpendicularity error for that size = 1.0.
So the answer is the one pylfrm gave earlier - 16.15.

Certified Sr. GD&T Professional

RE: pass rate for ASME Y14.5 certification test

EDIT: LMB = 151.5 would be correct if B was referenced primary datum feature at LMB in the position callout.

Since B has been called out secondary, LMB calculation must include orientation relationship between OD and the datum plane A. That makes LMB = 150.5 = 151.5-1.0.

RE: pass rate for ASME Y14.5 certification test

(OP)
Since the perp. callout is at MMC don't you have to consider the related actual mating envelope (outside of the material) and not the actual minimum material envelope (inside the material)? The smallest value the RAME could have is 151.5 which would be the feature made at its smallest size with perfect orientation to A. Is this perhaps why the question writer had 16.65 as the correct answer?

RE: pass rate for ASME Y14.5 certification test

pylfrm and pmarc (and AndrewTT, mkcski et al.) -- Thanks for the input. One other thing to think about though: the perpendicularity is only of concern if we are looking for the thinnest wall at one particular cross-section (depth-wise). The thinnest wall as a complete wall (throughout the depth) would be based only on the RAME. Thoughts?

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

RE: pass rate for ASME Y14.5 certification test

I am beginning to think there are two correct answers depending on your interpretation of the phrase "minimum permissible distance" from the question. Maybe??

Certified Sr. GD&T Professional

RE: pass rate for ASME Y14.5 certification test

The definition of the "minimum permissible distance", "minimum wall thickness" is subject to multiple interpretations. This is not the first example where we have seen that. GDTP preparation book from Robert H. Nickolaisen had a couple of these calculations and the answers are not the same amoung the experts.

So, UOS "unless otherwise specified" the definition is.......................
And yes, I know, you guys like to use the UOS note...bigsmile

RE: pass rate for ASME Y14.5 certification test

Quote (J-P)

One other thing to think about though: the perpendicularity is only of concern if we are looking for the thinnest wall at one particular cross-section (depth-wise). The thinnest wall as a complete wall (throughout the depth) would be based only on the RAME. Thoughts?
Well, not really, J-P. You may get uniform wall thickness of 16.15 throughout the entire depth. Take pylfrm's example again and imagine that the flat spot on the OD goes from the top to the bottom of the part. If the toleranced hole is produced at its LMC size and perpendicular to datum plane A, this will produce the uniform wall thickness.

Quote (mkcski)

I am beginning to think there are two correct answers depending on your interpretation of the phrase "minimum permissible distance" from the question. Maybe??
As greenimi said, it is not the first time on the forum when discussion like this ends up with conclusion that the answer may depend on what someone understands by "minimum permissible distance".

RE: pass rate for ASME Y14.5 certification test

I'd be looking at the smallest distance from any point on the surface of the hole to any point on the surface of the outer diameter.

RE: pass rate for ASME Y14.5 certification test

(OP)
If I have ~60 seconds on a test to give an answer to this question then I probably land on the 16.65 answer because I don't know that I could arrive at the 16.15 answer without 2D cad or more time to lay out a drawing manually.

Maybe they should have worded it "Assuming the part is made perfectly cylindrical...".

RE: pass rate for ASME Y14.5 certification test

AndrewTT: Since the 16.15 answer is not on the answer-list, by default I would choose 16.65 answer.

All: I really appreciate these discussions!!! They really allow me to "see" other approaches to what I thought was the "only way" Thanks.

Certified Sr. GD&T Professional

RE: pass rate for ASME Y14.5 certification test

Andrew,
Don't worry. I would not really expect this kind of questions on the Technologist level exam.

RE: pass rate for ASME Y14.5 certification test

Quote (pmarc)

Quote (Belanger)

One other thing to think about though: the perpendicularity is only of concern if we are looking for the thinnest wall at one particular cross-section (depth-wise). The thinnest wall as a complete wall (throughout the depth) would be based only on the RAME. Thoughts?
Well, not really, J-P. You may get uniform wall thickness of 16.15 throughout the entire depth. Take pylfrm's example again and imagine that the flat spot on the OD goes from the top to the bottom of the part. If the toleranced hole is produced at its LMC size and perpendicular to datum plane A, this will produce the uniform wall thickness.

Agreed. I chose that example because it works for all interpretations I could imagine for "minimum permissible distance between the outside of the part and the edge of a hole".

Additionally, the case where datum feature B is a perfect cylinder with diameter 151.5 and maximum perpendicularity error only yields a local wall thickness of 16.15 in the limit as the plate thickness approaches infinity.

I too would have chosen 16.65 from the options provided.

pylfrm

RE: pass rate for ASME Y14.5 certification test

Then the simple answer is to drop it from the batch of questions I posted there. No use making the question itself confusing. Thanks again all...

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

RE: pass rate for ASME Y14.5 certification test

Belanger,

I don't think the question itself is confusing in its current state, just the answer choices provided.

Quote (AndrewTT)

Maybe they should have worded it "Assuming the part is made perfectly cylindrical...".
This would actually make it worse I think. The answer would then depend on the interpretation of "minimum permissible distance between the outside of the part and the edge of a hole". If you go with "smallest distance from any point on the surface of the hole to any point on the surface of the outer diameter", then you'd have to use a perpendicularity error, but that depends on the plate thickness. Assuming a thickness of 12, which looks pretty close visually, the answer would be about 16.43. I wouldn't consider that very practical to calculate in a test without CAD software though.

pylfrm

RE: pass rate for ASME Y14.5 certification test

pylfrm - have you a sketch that shows that thickness affects the minimum distance? I don't envision perpendicularity as a consideration.

pylfrm - nevermind - I got it. It's what I would have done in making this calculation. It just needs a square root key on the calculator, not CAD.

This is easier when the fixture to check the part is the primary consideration and then allowable variation is superimposed over it.

RE: pass rate for ASME Y14.5 certification test

I'm actually fine with the notion of an indentation around the circumference (thus the answer does need to be changed), but my main concern is whether the wall thickness is to be found at only one spot, or throughout the thickness of the part. That's why it's not a good question for a test.

Attached is a quick sketch showing this dilemma. (You all can discuss it as much as you want, but I'm gonna yank the question.)

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

RE: pass rate for ASME Y14.5 certification test

Belanger,

I now realize that various combinations form and orientation errors can result in a local (point to point) wall thickness of less than 16.15, so I guess it does make sense to remove the question. Alternately, perhaps it could be modified to state that perfect form and orientation shall be assumed for all features.

This (along with thread1103-419878: Middle plane orientation) is a good example of how a characteristic that might appear to be indirectly controlled is often not really controlled at all.

pylfrm

RE: pass rate for ASME Y14.5 certification test

I like your suggestion, pylfrm. I've kept the question but modified it to assume perfect form and orientation.

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

RE: pass rate for ASME Y14.5 certification test

JP - I've thought for a long time that the standard should just adopt the perfect form /orientation explanation. Based on the number of people I have worked with who refuse to consider errors in form or orientation in their selection of datum references and analysis of tolerances it seems useful to simply be done with it and codify it. Plus it makes the math so much easier. As a practical matter, when asked about variations in form or orientation I'm always rebuffed with the same argument - 'they' wouldn't make it that way/it would be rejected for workmanship.

RE: pass rate for ASME Y14.5 certification test

Belanger,

Glad it could be saved. It certainly was an interesting question.


3DDave,

What do you mean by "the standard should just adopt the perfect form /orientation explanation"? Just as a simplifying assumption for some of calculations in the examples?

pylfrm

RE: pass rate for ASME Y14.5 certification test

Pylfrm,

Accepting as a general principal that orientation effects on positional tolerances not be considered, only such variations as parallel axis translations. The standard already ignores orientation contributions in Fig 4-16 (c) because it makes the math easier to manage. Perhaps the analysis of the figure is repaired in the 20xx public draft.

Looking at the desire to change the example problem suggests that this is the way the problem is typically analyzed. It isn't an example of a restriction on most drawings, but it is the typical.

RE: pass rate for ASME Y14.5 certification test

Quote (J-P)

I like your suggestion, pylfrm. I've kept the question but modified it to assume perfect form and orientation.
And now the perpendicularity callout you added at the beginning of the thread has become useless wink

Quote (3DDave)

I've thought for a long time that the standard should just adopt the perfect form /orientation explanation.
If done (which seems like is not going to happen in the 20xx version), it would have to be done very cautiously. I agree it helps to perform "hand" math, but unfortunately it may also lead to false conclusions in certain situations. In J-P's example, if the composite position callout applied to pattern of 5 holes was specified at RFS, the perfect-form-and-orientation assumption would lead to a different minimum distance between the outside of the part and the hole surface than possible without the assumption.

RE: pass rate for ASME Y14.5 certification test

pmarc,

I was going after only orientation; even so the result would be different values. But I think it would fit better with the incomplete understanding of the geometry that most users seem to have of what the allowances of variation can have on acceptable parts.

I've mentioned before my 3 buds who took the test, 2 passed, 1 failed. The one who failed didn't understand offhand why the projected tolerance zone formula in the 1982 version multiplied the base position tolerance by 2 in the portion relating to the projection zone ratio. Simple geometry, and he was contracted as a D&T expert. As long as he didn't have any problems that involved orientation, the answers were OK, but where orientation of the resulting feature could affect things? Not so good. I don't know about the other two because the question didn't come up for them.

I think it is rare for current machining technology to get parts that are sufficiently out-of-square to notice the allowable orientation errors. There was an entire military program that had been worked for years for TACOM that had no default angle tolerances and didn't use FCFs to control them. Parts would not have been rejectable per the drawing even if nominally 90º angles were 5º off, but no one noticed and parts fit. I mention TACOM specifically because they had developed a rule that there should be no default tolerances on angles. So the project team just eliminated that section from the title block. (The entire rule was that no dimensions should depend on a default tolerance and that all directly applied tolerances should be applied to the individual dimensions.)

So if a major military contract with deliverable drawings and customer sign-offs misses a critical orientation tolerance is missing entirely and the production of parts to that contract are delivered and used without noticing, then it seems like a good chunk of industry in insensitive to orientation requirements because the variation of the parts is smaller than a value that matters.

If true, and it seems to be true, then there isn't any point in including mention of orientation sensitivities, except as an appendix item for special applications. It would certainly simplify the test questions and fit within the limited mental model most users seem to have while not violating the performance expectations for actual parts.

RE: pass rate for ASME Y14.5 certification test

That's an excellent example of what I wrote earlier. The OB is held perpendicular, though there is no such limitation in the standards to do so.

RE: pass rate for ASME Y14.5 certification test

Quote (3DDave)

So if a major military contract with deliverable drawings and customer sign-offs misses a critical orientation tolerance is missing entirely and the production of parts to that contract are delivered and used without noticing, then it seems like a good chunk of industry in insensitive to orientation requirements because the variation of the parts is smaller than a value that matters.

So how did they calculate correct sizes of MMBs for secondary datum features of size relative to primary datum planes? Unless you want to say that they did not have to do it because they never specified secondary datum features at MMB and they never used hard gages to simulate datums. Is it really what the rest of the world do or should do?

RE: pass rate for ASME Y14.5 certification test

They didn't use datums for most of the features - straight-up conventional dimensioning and tolerancing. A rectangular plate could have been out of perpendicular by 5 degrees and not violated any drawing requirement, which had no limitation on the implied non-basic 90 degree angles.

I don't know about the rest of the world. Just the US DoD and our suppliers and our QA/QC never noticed or cared about the omission.

I have since worked at an FDA regulated company. While they did have angle tolerances, parts made to those limits could not be assembled, but they had no interest in changing them, because they just assumed the supplier would make usable parts regardless of the tolerance.

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