Projected Tolerance Zone

[[To...]]

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When I was reviewing Dan's posting of the ISO pics, I was also thinking the 25 long zone starting at 7 from A was bogus. However, I could see this with a position callout.

[[An...]]

It gets better and better.
Here's an example of the combination of:

1.) Perpendicularity
2.) Reference length (P)
3.) Maximum-Material-Condition

Contribution_27_04_2020_1.pdf

[[Da...]]

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Are you kidding me you just Said Totally Bogus to the ISO 1101 Standard. I know you think that your a expert but Sad to say you are not.
It is the ISO standard can't be bogus it is the standard.

Get some training.

Thanks Dan

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[[Da...]]

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Once again the ISO 1101 standard get some training fast before you get more your miss information out there.

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[[Da...]]

MMC is always on threaded features. This applies for both ISO and ASME.
This is the problem that happens with Inspectors that don't have training and never have read the standards even once.
Take some time and read the standard from cover to cover. There is the standards I never quote anything but the standards. If you don't know the standards then take some time and learn them. Then don't act like you understand it better then the team that created the standard everything in both standards are agued over for years before it is released. They have thought about it and the reason it is in there is it has a purpose. I am ASME certified and still get confessed by some of the callouts and why they are there but when we get in to those meeting there is always justified reasons for the creation of the call out.

I don't have access to my ASME Y14.5 2009 Right at this sec but I will get you the MMC for thread holes. For ASME

[[To...]]

Referring the "BOGUS" drawing, a perpendicularity to B with P = 32-7, would get the same result, if it was P = 132-107, or P = 25

[[An...]]

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I fully agree!
A standard should never be bogus.
Unfortunately the reality tells another story.

[[To...]]

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What's the point of having MMC on a threaded hole unless you are actually checking the pitch diameter? Bonus tolerance on the minor or major diameter does almost nothing with regard to how a fastener is located.

[[Da...]]

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I thought the same thing at one time it has to do with gauging. With out MMC you can't use hard Gauging for measurement.
But there is a Explanation in ASME 14.5 -2009 that I really like that talks about that threaded features negate bonus tolerances because it is a self centering feature. I will find the standard so I am quoting as it is written.

[[Da...]]

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This is talking about Projection it can be applied other GD&T callouts. It is not saying that it only applies only to Perpendicularity it can also applied to True Position. Just an example of how it is used and what defines the callout of (P).

[[Er...]]

Lots of pie throwing here, I love it! 😃

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Sounds like you are making a wild guess... Thats not true. Well the arguing, you got that one. For years?! Nah, I know a guy who used to be in the ISO comittee, and from what he say, everyone screams to get their will printed, apperently the french guys are the worst of them all. Like babies in kindergarten.. Anyhow, some of the ISO standard doesnt make perfect sense...

You can't really argue against that, if you truely understand everything in the ISO GPS.

I quote my self: "Yeah I can do that 😱 , but why?" 😎

[[Da...]]

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And I am not making a wild guess I am on the ASME Group and have been to the ISO group. Don't use hearsay.
But It is the standard if applied wrong engineers fault not mine. I do what the print is controlled by the standard and the standard is the controlling document. So you can ague all you want if it is write wrong but still the controlling doc.

[[Er...]]

Nah don't be silly. No one fully follow the ISO standard 🙂 Or you are lack knowlage of what Calypso actually do sometimes.

Oh, what subcommittee are you in?

[[Da...]]

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😕

[[Ia...]]

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Is this what you're looking for?

This is from ASME Y14.5-2018

Edit, just realized Tom posted this exact figure on page 1. Whoops

[[Da...]]

Yes that was it

Thanks

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[[SH...]]

What is happening here??? Is it President Trump debate??? 🤣

[[An...]]

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Here is a short summery of my work during the season 2019/2020.
Every file shown points out a severe fault in the standard.
Sorry to say that.

Summery_1.JPG

[[Da...]]

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Are they Faults? or do you not understand why it was used that way?
Don't always think that things you disagree with are faults.

This is not a Fault it is explaining Projection maybe a bad choose of GD&T callout for this example. But the projection standard is still correct and how to use the (P).
The definition is correct and it is clear how to apply it to a feature. This is not a fault.

[[An...]]

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No!

Contribution_27_04_2020_2.pdf

[[Da...]]

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You are the Problem
Get Training

[[Da...]]

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This happens if the Feature length is long but through plate is thin like sheet metal. You can allow for large Angularity and function will not be affected. Can this be checked in other ways? the answer is yes but it doesn't disqualify its use. Like every call-out there is another that can be used instead. This does not make the P of Perp bogus just a design intent.

[[An...]]

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From real geometries and virtual geometries.
See attached.

Contribution_28_04_2020_2.pdf

[[To...]]

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Please show me an example where the design intent affects the "location" of the evaluation range of a projected tolerance zone on a perpendicularity matters. Yes, it matters for a position callout.

[[Br...]]

Older revisions of Y14.5 placed the projected tolerance zone symbol below the FCF like that. The way you fellas are used to seeing it was first added in the 1994 revision of Y14.5. This could be an older drawing.