Cross out Standard Tolerances in Title Block

[outlawjj]

Our drawings contain "Unless otherwise specified" the following dimensions applied, ex. XXX=+/-.005 or edges shall be radius/chamfer.005/.015. A few of our customer drawings specify a different default radius/chamfer lets say .004/.012. So I place the new default tolerance in the notes. Should I be crossing out the tolerance in the title block? I treat it as "unless otherwise specified" and I do have the new specification in the notes so I have not been crossing them out. Is there a standard on doing this?

 

[JNieman]

I don't understand the problem.

A part is defined by the drawing containing it (among additional text or CAD data that may accompany it) so what conflict is there at all? You speak like you're trying to make two different title blocks work for one part. What is the nature of your situation where that could possibly happen?

What does your drawing have to do with your customers part, which has its own drawing?

 

[outlawjj]

The problem is our drawings have a radius/chamfer callout of .005/.015, which need to meet my customer's requirements of .004/.012.

In the past, my company has crossed out our tolerance of .005/.015 and placed a note stating the radius/chamfer tolerance is .004/.012. I believe this is incorrect as the title block states "unless otherwise specified" and I am specifying the correct radius/chamfer tolerance of .004/.012 in the notes.

 

[JNieman]

Are you recreating your customers drawing on your own title block?

 

[KENAT]

You can argue the 'unless otherwise specified' route but as it is a universal general tolerance I think it's a bit confusing having it in the block & in the notes.

So I'd probably go with the cross out in this case.

Posting guidelines faq731-376

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[MintJulep]

Just change the values in the title block.

 

[KENAT]

I'd actually vote against changing the numbers in the title block in some circumstances. If everyone is used to them being a certain value, then changing them tends to get missed.

Arguably still the person using the drawings fault for not properly reading it but having been involved in this kind of thing I now avoid changing standard format tolerance blocks in most cases.

Posting guidelines faq731-376

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(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[dgallup]

While you are correct that strictly speaking you don't need to cross out the title block default tolerances, I agree with KENAT that it can't hurt to cross them out. Just eliminates a possibility for error. We make our default tolerances parametric and read in the values from the model.

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[SwinnyGG]

If the customer's specification is .004/.012, than dimension the features with that tolerance. I, like JNieman, don't see the problem.

 

[outlawjj]

Thanks for all the good information. I think I will start crossing the title block tolerances out when they are superseded.

 

[BiPolarMoment]

The way I've handled this in the past is to put a flag note in the title block next to the default tolerances that then specifies in the notes the alternative tolerances. However, I have had many a time where people have failed to read the note and assume the title tolerance. Fortunately, I haven't yet received a bad part because of this oversight but it's bound to happen someday. Our drawings leave something to be desired for sure, and I'm not innocent in that charge.