Drawing tolerance

[dogbural]

Hi,

Is below the correct interpretation on the drawing tolerance specification?

specification 1 will override specification 2?

Thanks
MK

 

[pmarc]

dogbural,

Typically, #1 is used to control features that are defined with basic dimensions whereas #2 is for non-basic dimensions.

 

[greenimi]

pmarc,

This is the same as the unsettled argument about this figure. We disccussed it here:

https://www.eng-tips.com/viewthread.cfm?qid=503466

But we haven't reached any conclusions. At least I don't think we did find out any meaningfull way of interpreting this drawing.

When you say Typically what does that mean? Common understanding? Since we all know the UOS is anything but clear.

 

[powerhound]

From ASME Y14.5-2018

John Acosta, GDTP Senior Level

 

[greenimi]

So based on powerhound embedded picture, should we understand that the OP drawing is at fault?
Or it is good "as -is" and it is interpretable?

 

[Burunduk]

should we understand that the OP drawing is at fault?

It is, but from different reasons, not related to that part of the standard which was put in focus by powerhound here (are you guessing what they might be?). It is not invalid per ASME Y14.5.
The OP example doesn't state that untoleranced dimensions are basic. It might be clear from the drawing views (which we can't see) which dimensions are basic and which are toleranced. The Y14.5 rule indicates that the example from the other thread (the one you mentioned) is incorrect, and it was intended to prevent the ambiguity related to it. This rule was also brought up in the other thread.

 

[powerhound]

The OP example doesn't state that untoleranced dimensions are basic.

Note 4 seems to say that all dimensions are basic, unless otherwise specified. Is that not pretty much the same thing?

John Acosta, GDTP Senior Level

 

[greenimi]

powerhoud,

I think Burunduk is talking about the OP example where we don't have note 4 or something related with untoleranced dimensions as being basic

 

[Garland23]

Greenimi,
But if there is a general profile tolerance, doesn't that imply that profile applies to some basic shapes on the drawing?

 

[Burunduk]

powerhound,
There is no note 4 in the OP example.

 

[Wuzhee]

These drawings are the result of several years of reworking through a dozen departments and engineers across a company. One wants a general tolerance table, the other requires a standard callout, third wants basic dimensions etc. And everyone just slaps their table on the sheet without thinking for a second.