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GD&T reference

CyborgMetrology

Plastic
Joined
Aug 10, 2021
My birthday is coming up, and I want to ask the boss to buy me some books for the office. We definitely need a new-er copy of the Aluminum Extrusion Manual from AEC for any disputes with suppliers, our present copy is 1999. (250$) I'm looking for a GD&T Rosetta Stone for disputes with engineering...

On Friday, when nobody from engineering is in the facility, my coworker had to check a part that had six holes with countersink on the near side and four holes with countersink on the far side. The near side holes were drawn concentric circles to indicate countersink, the far side holes were drawn single-circle with the 4x (hole diameter)(countersink). The machinist came in spitting nails on Monday morning because his parts got red-tagged. Well, yeah, after you point at it and yell, it makes sense now, but NS does not mean near-side in GD&T and FS does not mean far-side... that's some homebrew horseshit right there. We don't have a book to point at when we're shouting at engineering...

I know engineers are supposed to be bad at English talky-talky, keep the customers away from them, but wtf?!? I worked a previous job where our best machinists were Serbians working 3months in America and trading-off with family back home every so often, but the engineers at that shop always made sure to translate through the owner and then check the translation through the old lady in the gage room... we've got no translators here because we're all talking English like it's the same language.

Help... book recommendation.
 
we've got no translators here because we're all talking English like it's the same language.

"I know you believe you understand what you think I said, but I'm not sure you realize what you heard is not what I meant."
 
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My birthday is coming up, and I want to ask the boss to buy me some books for the office. We definitely need a new-er copy of the Aluminum Extrusion Manual from AEC for any disputes with suppliers, our present copy is 1999. (250$) I'm looking for a GD&T Rosetta Stone for disputes with engineering...

On Friday, when nobody from engineering is in the facility, my coworker had to check a part that had six holes with countersink on the near side and four holes with countersink on the far side. The near side holes were drawn concentric circles to indicate countersink, the far side holes were drawn single-circle with the 4x (hole diameter)(countersink). The machinist came in spitting nails on Monday morning because his parts got red-tagged. Well, yeah, after you point at it and yell, it makes sense now, but NS does not mean near-side in GD&T and FS does not mean far-side... that's some homebrew horseshit right there. We don't have a book to point at when we're shouting at engineering...

I know engineers are supposed to be bad at English talky-talky, keep the customers away from them, but wtf?!? I worked a previous job where our best machinists were Serbians working 3months in America and trading-off with family back home every so often, but the engineers at that shop always made sure to translate through the owner and then check the translation through the old lady in the gage room... we've got no translators here because we're all talking English like it's the same language.

Help... book recommendation.

I found the book "Fundamentals of Geometric Dimensioning and Tolerancing" by Alex Krulikowski, to be helpful.

It explained things fairly well, using a lot of drawings, and gauge/measurement examples.

Regards,

William
 
We used to send all of our new employees and interns through a GD&T online course. It's a good intro, but nothing like reading the spec.
Your issue sounds more like a print reading or communication issue though. If you see some letters on a drawing and aren't certain what they mean, ask around until you find the answer. I'd much rather get a call on my cell at 9 PM than walk in the next morning to find parts I can't use.
Nearly all of the shops I work with now, domestic or international, including the in house one, insist on a .step or other 3d format file before they start work. It does require that the models be solid, but it also has all but ended the occasional "What is this view showing?" questions.

One downside to reading the standard is that you'll find a huge portion of people have learned it through tribal knowledge and are not using it correctly. Resolving those issues is a different problem.
 
Sounds like a few issues:
1. If specifications aren't going to be spelled out in actual words, ("near side" "far side"), then you should have the terms/abbreviations used by engineering, or whoever is making the drawings, defined in a set of company-specific manufacturing standards. This is frequently done in larger companies that can afford the documentation overhead.
2. Use of hidden lines would have made it immediately obvious as to intent of the drawing. Many drawings these days omit hidden lines to make the drawing less cluttered, more readable, etc., but this isn't an "always" situation IMO.
3. It isn't clear to me that a typical GD&T reference is going to be prescriptive in terms of how to label near-side/far-side features. If, on the other hand, you DON'T have a reasonably current ANSI y14.5 standard copy, you should.
 
I would also recommend a Wall Chart. Look at WordPress › Error . There is a lot of info in the ASME Standards. Also, GD&T and Drafting changes some what to a lot from version to version.
 
I second this!! I use both the textbook and the pocket handbook almost daily. Also, GD&T Basics offers a free poster too. Very useful to have around the shop.
 
Just get a copy of ASME Y14.5

While you are at it, get a copy of Y14.100 too.


While you're shopping, add a copy of ASME Y14.38 - Abbreviations and Acronyms for Use in Product Definition and Related Documents.
In there you'll find that backwoods horsepuckey 'NS' and 'FS' abbreviation business is actually defined and that good for nothin' honkey Engineer in your shop actually used the abbreviations correctly.

ASME Y14.38-2019_FS.jpg

ASME Y14.38-2019_NS.jpg
 








 
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