Customer Rejecting Part for Basic Dimension

Cari Spears

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While I'm new to the industry, I know that this is a "basic dimension" and does not have a tolerance. Without a tolerance I don't know how to make this a conforming part because I know there is no way for us to achieve a perfect part that is 63.5000 mm long.
...
Should the drawing contain other information about the length?
One big take away from here for you, I hope, is that basic dimensions do have tolerances.
 

Michael_M

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I wondered why everyone was missing the "Both Sides" note.

I saw it and "ignored it" based on the training from a long time ago. I probably miss-remember but I remember being told that profiles needed to be called out on each surface specifically if they apply or a 'designation' line indicating where the profile starts or ends. I may be translating a 'customer' requirement to a general requirement, like I said, I was trained long long ago in a galaxy far far away with several bad drawing between.
 

Miner

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I saw it and "ignored it" based on the training from a long time ago. I probably miss-remember but I remember being told that profiles needed to be called out on each surface specifically if they apply or a 'designation' line indicating where the profile starts or ends. I may be translating a 'customer' requirement to a general requirement, like I said, I was trained long long ago in a galaxy far far away with several bad drawing between.
That would be a much better way to dimension a drawing. This drawing was poorly dimensioned and open to interpretation. Exactly what GDT was designed to prevent.
 

Ron Rompen

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Cari is correct - the total 'tolerance' is ± 1.5 (.75 for the profile tolerance, and .75 for the perpendicularity tolerance).

Check the parts that they are rejecting, and ensure that the profile and perpendicularity are within tolerance. If they are, then the parts are conforming and not rejectable. The 'basic' dimension is a theoretical construct, which is used to define the location of the profile zone. It cannot be measured.
 

thehovie

Registered
After reading the later responses, I pushed back to our customer on having an ambiguous print and rejecting based on a basic dimension, while we were conforming to all toleranced dimensions and callouts. They're design team reviewed it and agrees! They are going to revise the print and issue a temporary deviation until it is effective. Thanks for your help guys!
 
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