Implied 90 degrees: Is it enough?

[GDT2009Rules]

I have searched through all the threads and reread Y14.5 but still can't articulate the answer to settle this argument so I'd appreciate some opinions.

The flange in the weldment drawing pictured is welded to a pipe which is in turn welded to a plate. The flange (detailed on a separate drawing) has two small holes on a diameter.

The weldment drawing has a title block angle tolerance.

Is "implied 90°" enough to control the orientation (rotation) of the flange as shown to within the title block angular tolerance or are additional control needed?

Hope this makes sense, and thank in advance.

 

[ctopher]

It depends on the shop making it. It's somewhat implied, but technically the way it's shown the holes can be any orientation.
If in doubt, dimension it.

Chris, CSWA
SolidWorks 14
SolidWorks Legion

 

[3DDave]

The problem with the implied 90 rule is that it requires checking all possible combinations of 90 degree pairs and doesn't clearly apply to separated features - for example, clocking on one small hole or the other or clocking on the combination of two holes relative to a third.

It is best relied on when there is no intention to closely check the result, as when confidence in the general skills of the fabricators exceeds the perceived need for precision. Many warships and clockworks were made with that technical understanding.

The development of feature control frames and geometric characteristics was to make plain what features of a design are related to one another and in what way. It makes recording those relationships easier, but you could write a note that describes the desired outcome. It's there is you need it.

 

[KENAT]

I'd err on the side of no it's not adequate for your situation, unless you have some other annotation etc. not shown in your sketch.

Refer to ASME Y14.5M-1994 2.7.3 for my reasoning thread1103-344036

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