Y14.5-2018 Published 1

[pmarc]

This is just to let you know that new version of Y14.5 is available.

https://www.asme.org/products/codes-standards/y145-2018-dimensioning-and-tolerancing

 

[greenimi]

Thank you pmarc.

I am proposing something: to find mistakes in it.

I am sure training companies will update their training material (what is changed, what is new, what is removed etc.) but for us, here on the forum, finding errors is more fun.
What do you think?

 

[pmarc]

greenimi,
We can try to find mistakes but at this point I would be more interested to see what others think about the document itself. I know there are different opinions about it.

 

[fsincox]

I got mine last week and have been anxiously awaiting its arrival on the board, I am interested also in what people think.
Concentricity and symmetry gone, plus and minus for location almost gone, and a new dynamic profile?
Frank
Thanks again pmarc

 

[dgallup]

I hate revised standards, just opens more cans of worms.

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[3DDave]

After the extensive public comment period and the way they posted all the issues and proposed fixes I have no doubt this version will be error free. /s

I guess they redefined position to absorb symmetry and concentricity?

I wonder if it has clear support for my contention that a wedge shape can have a flatness tolerance applied to it, owing has to how a wedge has a median plane.

 

[mkcski]

3DDave - I'm curious, how/where did you "find" the posts of the comments to the Draft? I am not a ASME member. Where they only available to Committee members?

I pre-ordered a copy and am waiting for it to arrive.


Certified Sr. GD&T Professional

 

[3DDave]

/s = sarcasm. There's no way they would have an actual, publicly exposed development process.

 

[axym]

pmarc and All,

The comments from committee review and public review were discussed and dispositioned in meetings that are open to the public, but these discussions are not published and are not to be discussed publicly. So only those who were there will know what really happened.

The new development that I like the best is dynamic profile. I think that this will be a useful addition to the toolset.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[chez311]

Evan,

dispositioned in meetings that are open to the public, but these discussions are not published and are not to be discussed publicly

I'm sure everything has its reason, but those two things seem slightly contradictory.. I wish there was more transparency in this regard - seems like this is a commonly shared sentiment from the recent posts/responses.

That being said, I wasn't aware these meetings were open to the public - I guess they would they be posted in the general "committee meetings" (

http://calendar.asme.org/home.cfm?E...34.988888701.1550776529-994293487.1547843827)

portion of the ASME site?

I also share your interest in dynamic profile, I remember you mentioning it a while back and I have been looking forward to see how it is implemented.

 

[greenimi]

Evan,
Which transition you would consider more impactful for a better product definition: from 1994 to 2009 or from 2009 to 2018? Otherwise stated, which standard has more beneficial changes, clarifications, etc: 2009 or 2018?

As for the 2018: I do not like the change in the stabilization procedure for irregularities on datum features applicable at RMB. And that’s probably because I am not understanding it. Candidate datum set has been there for long time and is kind of known (at least for me).
Single solution that minimizes the separation….hmmm.

 

[greenimi]

And one more of my pet peeve: why 2018 version did not put the brakes on using (legally) total runout on a cone?
Just saying the total runout will control cylindricity (in addition to others) is good enough? I remember some discussions where has been concluded that might not be sufficient (in outlaw the practice)

 

[chez311]

greenimi,

I haven't seen the new standard yet, but recalling the first instance where I heard about dynamic profile in this thread (

https://www.eng-tips.com/viewthread.cfm?qid=439427)

it was in reference to how it would make the debate over whether total runout is legal for conical features *moot as the new dynamic profile could probably be used instead. See Evan's post on (1 Jun 18 17:05) - are there any examples of this in the 2018 version?

*edit: missing a word

 

[greenimi]

Chez311,
What moot?

My question is: how would you divert people of not using total runout on cones?
Just because you have another method of defining the cones will not be good enough.

Make it illegal would.

 

[Belanger]

The new development that I like the best is dynamic profile.
I think that this will be a useful addition to the toolset.

You and me both, Evan. I recall our mutual dislike for Figure 8-18 in the 2009 standard. Maybe it's true that squeaky wheels get the oil!

 

[pylfrm]

[pre]
ASME Y14.5M-1994: 196 pages
ASME Y14.5-2009: 184 pages ( 94% of previous)
ASME Y14.5-2018: 309 pages (168% of previous)
[/pre]
I probably shouldn't complain before actually seeing the new standard, but this certainly seems like progress in the wrong direction.

Something written by Antoine de Saint Exupéry comes to mind:

It seems that perfection is attained not when there is nothing more to add, but when there is nothing more to remove.

pylfrm

 

[3DDave]

The key isn't making any particular language feature legal** or not; it is providing unambiguous declarations of applicability and clear rules for the expected results of application.

If total runout is described as a control limiting variation as measured by moving parallel or perpendicularly to an axis, as applicable, it automatically rules out cones and arcs and other shapes.

Is there something about dynamic profile that would not have fallen under the composite tolerance rules? Excepting that the '2009 and earlier simply didn't show an example?

**By definition, any language feature as expressed in the language spec is legal, just like any rule in a board game is legal for the game. They may also be ill considered, contradict some other part of the specification, or have some basic defect in the way it reflects the application domain.

 

[pylfrm]

Is there something about dynamic profile that would not have fallen under the composite tolerance rules? Excepting that the '2009 and earlier simply didn't show an example?

Yes. In the draft, dynamic profile was basically a generalization of total runout to things other than surfaces of revolution. I assume this hasn't changed significantly.


pylfrm

 

[chez311]

The key isn't making any particular language feature legal** or not; it is providing unambiguous declarations of applicability and clear rules for the expected results of application.

greenimi,

I meant the argument between whether total runout on cones is legal or not would become moot/irrelevant. However 3DDave hit the nail on the head. I could be wrong, but I don't think the standard spends much time on what is not allowed or specifically stating something as "illegal". Instead it is typically more important to as clearly and specifically as possible define rules and applications for each topic (which, if we're being honest it comes up short in several areas... but no standard is perfect I guess - or at least I'll keep telling myself that).

Take for example the rules for position tolerancing. I don't believe the standard says anywhere "directly toleranced dimensions are not allowed/illegal in combination with position tolerance". Instead it specifically states in 7.2 "Basic dimensions establish the true position from specified datums and between interrelated features" and only shows examples with basic dimensions. The logical conclusion would be that position tolerancing and the definition of true position is only allowed with basic dimensions, and any use of directly toleranced dimensions would violate the definition of position and would have no support in the standard as to how to interpret it.

 

[greenimi]

So, let me ask then what would be the purpose of adding cylindricity to the 2018 version on the total runout definition? To clarify what? Why not keep it the way is it in 2009?