Talk:Geometric dimensioning and tolerancing

GDT undefined

The most interesting aspect to the topic Geometric Dimensioning and Tolerancing (aka GD&T) is that the document most often refered to as basis, ASME Y14.5M-1994, has no definition for Geometric Dimensioning. The Document title is "Dimensioning and Tolerancing." Also, when you become certified by the ASME you take the Geometric Dimensioning and Tolerancing Professional exam (GDTP exam).45.48.101.15 (talk) 06:03, 24 February 2015 (UTC)

The term GD&T is likely the outgrowth of a major proponent, Lowell Foster, who wrote introductory texts called Geometrics, but it is just as likely a marketing term developed by one of the huge number of trainer/consultants in the field of 'Y14.5 application. In the scope of the standard, it is slang.

Geometric tolerancing is defined (paraphrased) as applying to variations part surfaces and derived features, such as axes.

All that aside, the underlying value of the standard is to provide a set of common terminology, and reference methods.

---

The latest version, ASME Y14.5-2009, has removed the last vestige, the term 'geometric dimensioning,' from the body of the standard. It used to exist in one paragraph, and was never defined and never referred to. Three d dave (talk) 04:48, 16 June 2012 (UTC)

Datum References

"These are then referred to by one or more datum feature references which indicate measurements should be made with respect to the corresponding datum feature(s) found in the datum reference frame."

Measurements are not made based on the datum feature, but from the datum simulator. The datum feature is brought into contact with the datum simulator, which is to be of such quality as to be indistinguishable for the purpose from the theoretically perfect datum (gage maker tolerances)45.48.101.15 (talk) 06:10, 24 February 2015 (UTC). In application, one can fix precision angle blocks on a CMM as datum simulators, probe them to establish soft datum simulators, and then bring the part datum features into contact with the datum simulators and check features that reference the datums. Three d dave (talk) 04:48, 16 June 2012 (UTC)

ISO Equivalent

I was wanting to know if there is an ISO document that covers what the ASME Y14.5 document has. any help here would be great.

The ISO standard may have slightly less symbols than what ASME Y14.5 has, but ISO has the same basic content from what I understand. There seems to be several ISO documents for GD&T. It appears ISO split it up into several different sections from datums to runout. Purchasing them all may cost over $1000. Logic would tell one there should be an overiding document that specifies each section, but this remains to be seen. Maybe someone at BMW would know more about the ISO equivalent. — Preceding unsigned comment added by 45.48.101.15 (talk) 06:39, 24 February 2015 (UTC)

re: ISO Equivalent

The ISO breaks the concepts contained in 'Y14.5 into a number of smaller documents. ISO 2692-1998 covers MMC principles. Unless it's been replaced, the root document is now ISO 1101:2017. See http://www.iso.org/iso/en/CatalogueListPage.CatalogueList?COMMID=4647&scopelist=

Lothartklein 07:00, 22 June 2007 (UTC): There is not only a single ISO standards but a whole bunch of them and at least 3 ISO committees are producing GD&T standards (TC10, TC213, TC184) from different perspectives (drawing, product, CAD exchange). I added a few but there are several more for specific areas.

Image

Aside from the article being far too brief, I'd like to point out that the two parts illustrated in the intro to the article at the top of the page are NOT the same. Your feature control frame should have a .040 positional tolerance if you want them to be more similar. Incase you're interested in actually conforming with ASME Y14.5-1994 —Preceding unsigned comment added by 12.71.226.254 (talk) 21:16, 7 July 2009 (UTC)

Per the above comment and the one that was just made in the article, I updated the image to remove the standard tolerances and just show GD&T tolerances. Wizard191 (talk) 02:22, 10 January 2011 (UTC)

The image incorrectly omits a Diameter symbol before the .040 tolerance. When locating a hole, the tolerance zone is in the shape of a cylinder, in this case with a Diameter of .040. Therefore, you must place a diameter symbol in front. Secondly, you can only locate a feature of size. This means, you must dimension the hole with a tolerance, and then place the feature control frame defining location below it. The main image omits this, and incorrectly points the feature control frame directly at the surface of the hole. See of Section 7.2.1.3 of Y14.5-2009. --Bruno.caulk (talk) 22:19, 28 February 2020 (UTC)

I'm going to re-do the (first) symbols chart

I'll be copying the first symbols chart to my sandbox, and completely re-doing it. I'm going to make it to closer match a chart I have that's based upon ANSI Y14.5M-1982. Thank you to who ever made it in the first place, so that 13 of the 14 the graphic symbols are already made. Anybody know who did make the graphics? I will need the "Location-Symmetry" symbol to finish the chart.
LP-mn (talk) 13:16, 26 August 2009 (UTC)

Just out of curiosity, why are you remaking them? Are you going to make SVG versions? Wizard191 (talk) 16:39, 26 August 2009 (UTC)

If you update this to 2009, flatness can be applied to a feature of size it would affect the midplane it that case. — Preceding unsigned comment added by 71.154.217.130 (talk) 20:02, 8 August 2012 (UTC)

Symbols chart; new candidate to replace the....

For those of you who frequent the GD&T page, please revise and/or comment on the below chart. I propose it replace the existing symbols chart, either in its present form, or when more completely fleshed out (See the Symmetry line of chart).

Geometric tolerancing reference chart
Per ANSI Y14.5 M-1982

Type of tolerance	Geometric characteristics	Symbol	Can be applied to a feature?	Can be applied to a feature of size?	Can affect virtual condition?	Datum reference used?	Can use modifier?	Can use modifier?	Can be affected by a bonus tolerance?	Can be affected by a shift tolerance?
Form	Straightness		Yes	Yes	Yes (note 1)	No	Yes (note 1)	No (note 5)	Yes (note 4)	No
Form	Flatness		Yes	No	No	No	No	No (note 5)	No	No
Form	Circularity		Yes	No	No	No	No	No (note 5)	No	No
Form	Cylindricity		Yes	No	No	No	No	No (note 5)	No	No
Profile	Profile of a line		Yes	No	No	Yes (note 2)	No	No (note 5)	No	Yes (note 3)
Profile	Profile of a surface		Yes	No	No	Yes (note 2)	No	No (note 5)	No	Yes (note 3)
Orientation	Perpendicularity		Yes	Yes	Yes (note 1)	Yes	Yes (note 1)	No (note 5)	Yes (note 4)	Yes (note 3)
Orientation	Angularity		Yes	Yes	Yes (note 1)	Yes	Yes (note 1)	No (note 5)	Yes (note 4)	Yes (note 3)
Orientation	Parallelism		Yes	Yes	Yes (note 1)	Yes	Yes (note 1)	No (note 5)	Yes (note 4)	Yes (note 3)
Location	Symmetry		? (note 6)	? (note 6)	? (note 6)	? (note 6)	? (note 6)	? (note 6)	? (note 6)	? (note 6)
Location	Positional tolerance		No	Yes	Yes	Yes	Yes	Yes	Yes (note 4)	Yes (note 3)
Location	Concentricity		No	Yes	Yes	Yes	No	No (note 5)	No	No
Runout	Circular runout		Yes	Yes	Yes (note 1)	Yes	No	No (note 5)	No	No
Runout	Total runout		Yes	Yes	Yes (note 1)	Yes	No	No (note 5)	No	No

NOTES:

1. When applied to a feature-of-size
2. Can also be used as a form control without a datum reference
3. When a datum feature-of-size is referenced with the MMC modifier
4. When an MMC modifier is used
5. Automatic per rule #3
6. The symmetry symbol's characteristics were not included in the version of the chart that this chart is derived from.

The handout that held the original chart that this chart was derived from is about twenty years old. I suspect it was copyrighted, but by whom is unknown. I can provide no guidance as to what note 5 means, nor do I have an intimate, detailed knowledge as to the definitions of each of the column headings. I present it to those who are participating in editing the section in the hopes that they can flesh it out some more.

It looks pretty good overall to me. My notes are:

• What does "al tolerance" mean in the position cell?

The original table had "POSITION", my table had "Positional Tolerance", I wrote it that way to show you and others who watch this page that this box's label has slightly changed. Same situation with "PROFILE (of a Surface)".

• None of the text should be full caps, per WP:MOS.

Fine, I have changed the YESes to Yes and the NOs to No. BUT... Did you mean that the first two columns (that are largely on the original table) should ALSO be in lower case?

• Why is the symmetry row italicized? Wizard191 (talk) 17:31, 27 August 2009 (UTC)

See Note 6 - The italics were done to emphesize (sp?) that this information is not included on my source material.

LP-mn (talk) 02:26, 28 August 2009 (UTC)

tweaked... LP-mn (talk) 02:42, 28 August 2009 (UTC)

I've just changed the parenthetical entries and some other small copy-editing, but otherwise I say go ahead and copy it into the article. It looks good. Wizard191 (talk) 13:18, 28 August 2009 (UTC)

---

Hi, man! I just touched this kind of symbols when doing a software development project for my friend's client few months ago. For easy to track and use, I modified the current two small tables referred to this PDF documentation I found online. You can ask the engineers working on inspection for component industry about some meanings that confusing you on the huge table above. Well, it's sorry that I'm not a pro-guy on it.--Gzyeah (talk) 06:32, 28 August 2009 (UTC)

---

I just tweaked the table one more time. This time I changed the 1st two column's UC to lower case, and made the 2nd column bold. —Preceding unsigned comment added by 204.77.52.227 (talk) 13:37, 31 August 2009 (UTC)
LP-mn (talk) 00:00, 1 September 2009 (UTC)

I've done one more pass at the formatting and I'll copy it into the article now. Wizard191 (talk) 14:25, 31 August 2009 (UTC)

I'm going to move the two Profile symbols up higher on the table to match the other example (pdf WH2...) and I'll add a link to that pdf as well in the external links section.
LP-mn (talk) 01:24, 1 September 2009 (UTC)

LP-mn (talk) 01:26, 1 September 2009 (UTC)
Copying and Pasting tweaked version to the web page.LP-mn (talk) 01:30, 1 September 2009 (UTC)

---

The line containing Symmetry should be removed as it was specifically removed from the 1982 version. It was re-introduced in the 1994 version because the position control did not perform as the symmetry one does. Alternatively, change the table to reflect all versions, and flag those symbols and modifiers where they do not apply.

Rule 3 is that anything that is not a position control is assumed to apply RFS when not otherwise specified.

Who killed the (M) column? Please put the heading back.

Table note 6 should read "Symmetry was dropped from the 1982 version and reinstated in the 1994 version. Nothing happened about 1988.

Three d dave (talk) 04:31, 16 June 2012 (UTC)

Current Specifications

ASME Y14.5M - 1994 has been replaced by ASME Y14.5 - 2009. From ASME's website:

The Y14.5M standard establishes uniform practices for stating and interpreting dimensioning, tolerancing, and related requirements for use on engineering drawings and in related documents. [Geometric Dimensioning and Tolerancing (GD&T)] For a mathematical explanation of many of the principles in this standard, see ASME Y14.5.1M. Practices unique to architectural and civil engineering, land, welding symbology are not included.

Y14.5 is a replacement of Y14.5M.

http://catalog.asme.org/Codes/PrintBook/Y145M_1994_Dimensioning.cfm (italics added)

ASME Y14.5.1M - 1994 (the mathematical definitions of the GD&T tools) is still current. 65.112.42.83 (talk) 14:19, 7 May 2010 (UTC)

Additional information - from AMSE sales page:

Important changes in the new ASME Y14.5 – 2009 Standard address: concept of feature of size; datum references and degrees of freedom; composite position tolerances; surface boundaries and axis methods of interpretation; profile tolerances; and symbology and modifiers tools. Additionally, the subject matter has been restructured for better readability, with profile, orientation, and form now in separate sections, and material within sections reorganized. http://campaign.asme.org/gdt/about.cfm

An article about the changes can be found at: http://machinedesign.com/article/new-asme-y145-2009-standards-for-gdt-1020

In my observation, it is not clear whether Y14.5M is obsolete. ASME still sells the old Y14.5M specification; however, they explicitly state that Y14.5 replaces Y14.5M. The document technical specification provider that my company uses (IHS, Inc.) does not have Y14.5M available anymore, but many companies still use the Y14.5M specification. 65.112.42.83 (talk) 14:44, 7 May 2010 (UTC)

I'm not sure what your question is, but if it is "what is the current ASME spec?" then you answered your question with "Y14.5 is a replacement of Y14.5M.". It's quite common to be able to purchase old specs. Wizard191 (talk) 16:40, 7 May 2010 (UTC)

The "M" stands for "metric". All the "M" means is that the examples in the standard use mm instead of inch. Y14.5 is the subcommittee that has the authority to make new revisions, not the standard. The most current standard is Y14.5M-2009, but that does in no way mean that Y14.5M-1994 is obsolete. In the facility I work in, we keep several old standards available because there are many old drawings that will forever utilize the older standards, and will therefore need to be interpreted relative to those older standards. So I would say that the older standards never really do become "obsolete". Gdtps0566 (talk) 14:49, 22 June 2010 (UTC)

Just a small note: I think the standard is called Y14.5 per [1], which states: "The Y14.5 standard...". Wizard191 (talk) 16:43, 22 June 2010 (UTC)

Yeah, I should have said "not the standard per se". It's just that when you start talking about specific releases, you pretty much should include the year. When we reference the standard in our facility, we say "1982", "1994", "2009". Do you know why they dropped the "M"? Gdtps0566 (talk) 17:06, 22 June 2010 (UTC)

This states that they "no longer deemed it necessary", whatever that means. Wizard191 (talk) 17:33, 22 June 2010 (UTC)

I can't believe I put the "M" in there for 2009. Gee, that's not embarrassing at all. Oh, well. I'm 1994 certified, that's my excuse. "Metric compatible"... yeah, what's the point? A unit is a unit, isn't it? If that's all it was for, no wonder they dropped it. Is there any concerted effort going on right now to improve this article? Gdtps0566 (talk) 18:16, 22 June 2010 (UTC)

Nope. The last big edit was August 2009. Feel free to help in any way. Wizard191 (talk) 18:47, 22 June 2010 (UTC)

Include ISO

This Article has to be extended for ASME Y14.5-2009 and the new/updated ISO TC213 standards in this field. "Geometric Dimensioning and Tolerancing" is a generic term and can therefore not be restricted to Y14.5. For the purpose of wikipedia and because of the huge overlap we have to address both sources (ISO and ASME) in the same article and as useful highlight the major differences. Lothartklein 19:31, 28 December 2010 (UTC)

Roughness?

FYI: I just asked a question I could have put here as well on the roughness talk page. —Ben FrantzDale (talk) 14:31, 9 February 2011 (UTC)

Your question properly belongs at Talk:Surface_roughness, because GD&T doesn't relate to surface finish. Wizard191 (talk) 15:40, 9 February 2011 (UTC)

ASME or ANSI??

The table and one more place gives standard as "ANSI". Is it a typo? I always thought Y14.5 is ASME and never heard or came across ANSI equivalant 166.214.172.224 (talk) 20:45, 28 March 2011 (UTC) Adi

Fixed. Wizard191 (talk) 17:46, 29 March 2011 (UTC)

The first table correctly referred to ANSI Y14.5M-1982 because ANSI had jurisdiction over it back in 1982. Since then ASME took over jurisdiction, therefore ASME Y14.5m-1994 & succeeding that ASME Y14.5-2009 (notice that they dropped the "M" which stood for metric). Why is the first table referring to the 2009 version?

Did I miss any mention in the article about ASME Y14.5-2009? If not, it should be there. — Preceding unsigned comment added by 72.22.191.68 (talk) 14:49, 19 October 2011 (UTC)

Symbol Table Note 6

This note says "(It's been speculated that it will be re-dropped the next time the standard is revised.)" and the standard has been revised. Has this been dropped?208.12.102.4 (talk) 15:31, 31 January 2012 (UTC)

Symmetry was dropped from the 1982 version, reinstated in the 1994 version, and remains in the 2009 version. Three d dave (talk) 04:33, 16 June 2012 (UTC)

Citation request in the "philosophy" section

I'm not comfortable with the two sentences I added citeref tags to, they seem too much like personal research/opinion. If they are indeed true, there should be some way to include a valid reference to them.69.207.144.29 (talk) 16:03, 6 June 2013 (UTC)

ISO GPS and ASME update

I feel like ASME information is outdated. Last issue of ASME Y14.5 is from 2018 (ASME Y14.5:2018).
I also feel like ISO GPS ('Geometrical Product Specification') desserves a new article as it is not an ASME equivalent but a completly different set of standards (see ISO TC 213 presentation)
--JfMaurel (talk) 09:59, 4 February 2021 (UTC)