Parts defined with point tables and no tolerances or dimensions

[RLD89]

I see a lot of parts with surfaces that have complex curvatures. Drawings(only) define the parts and those complex part surface features. Many drawings have hole locations in the part defined with point tables (with 3 place X,Y,Z coordinates). The drawings have no datums, no tolerances and no dimensions (except for hole sizes). To me, this implies default title block tolerances of +/-.010, and so, I assume a profile of .020 applies to each surface. I suppose we could simply say this is an incomplete drawing, but parts have been made, subject to any number of interpretations,. I need some basis for assumptions in order to do a tolerance stack up on an multi part assembly, which not so surprisingly has many problems.
Any suggestions or comments?

 

[drawoh]

RLD89,

If the drawing has no tolerances, you cannot inspect the part. Specifying datums means that everyone fixtures to the same point. If there is no agreement or control over this, the part is not inspectable.

--
JHG

 

[powerhound]

Agreed. You're chasing phantoms by trying to guess at this.

John Acosta, GDTP Senior Level
Manufacturing Engineering Tech
SSG, U.S. Army
Taji, Iraq OIF II