How to model part with specified minimum dimensions 1

[cinnamongirl]

How do I model 3D part features that are only specified by minimum dimensions? The drawings I'll be making from these 3D parts will only call out minimum dimensions on certain features because that's what the ASME standards specify.

For example, I have a coupling which must maintain a minimum wall thickness according to the ASME standard. Do I model it according to the minimum thickness? Or do I make the walls slightly thicker and override the value on the drawing dimension to specify the minimum? The coupling is cylindrical and if I make the walls slightly thicker it will minimize the amount of machining necessary because the overall diameter will be closer to diameter of the stock material.

Thank you.

 

[pylfrm]

Does this meet CAD and dimensioning standards?

I don't think you've said which dimensioning standard you're aiming to meet. Is it some version of ASME Y14.5? Does your drawing specify that it be interpreted per this standard?

What you've show appears unclear. The "2X 7/16" apparently doesn't have a tolerance, so it doesn't express any requirement. The "3/8 MIN" is enclosed in parentheses which (if interpreted per ASME Y14.5) identifies it as reference, making it a non-requirement as well.

Why not just specify "2X .4375 +/- .0625" or something like that? It seems like you'd need to specify both a high limit and a low limit unless there's some other relevant tolerance not shown in your image.


pylfrm

 

[ctopher]

I agree with pylfrm.
I have never seen a dim like that before that follows ASME.

ctopher, CSWP
SolidWorks '17
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[cinnamongirl]

My dilemma is I want to show both the dimension of the parts that have already been made (in order to maintain some consistency with new parts that will be made from my files) and the minimum requirement as given in the spec sheet, expressed as a MIN, for inspection purposes.

I guess I could use "2X .4375 +/- .0625" as pylfrm suggested (I should also add there is no maximum stated in the specs, but it must stay within a reasonable range).

 

[ctopher]

The dim/tol should match what the part is, or will be, on the drawing. This is what the part will be inspected to.

ctopher, CSWP
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