Another GD&T Question

Good afternoon.

Is it true that positions that are called out on a detail drawing do not pertain to final drawing? For instance, we will be running a part that calls for true position callouts on the detail level. On the final part, bosses get welded into the holes. Does the true position callout no longer apply on the final weldment since it is not called out on the final weldment print? So when the part gets welded and the bosses flex one way or the other, we will still have a good part? Is this a quality standard or simply based on customer preference?

Thank you.

Wes Cisco over 4 years ago

Not a quality standard. Not really a customer preference. More like a design/functional requirement.

tl:dr The final drawing should define all the relevant characteristics the final part must meet.
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Rich P over 4 years ago

Y14.5 Rev 2009, Dimensioning and tolerance reference section 1.4 Fundamental Rules
(o) Dimensions and tolerances apply only at the drawing level where they are specified. a dimension specified on one level of drawing (e.g., detail drawing) is not mandatory for that feature at any other level (e.g., an assembly drawing)

I think this is what you are looking for, this is 2009 not sure if that was changed on latest and greatest
that being said your customer may require proof of conformance at the component record, an inspection report
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ThePudds over 4 years ago

Engineers' do not always think to the next steps of the manufacturing process. They could just assume that the true position will be controlled by the child part. Most engineers' think of there part in a 3D state of existence rather than in a literal state. I have came across this many times with my engineers'.
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