Angularity - When angularity is called out should it be to a basic dimension

jfbock · Jul 16, 2010

Simple question I am having a hard time finding a concrete answer on.

When angularity is called out, should the angle it refers to always be a basic dimension? Wouldn't the angularity callout BE the tolerance for the angle.

I have a customer print that has angularity only as a callout (no form tolerance) and a regular (non-basic) angle callout. My understanding is this is not correct.

Appreciate any help.

True Position · Jul 16, 2010

Re: Angularity

You are right that this is not correct. Either you are measuring the angle(traditional result in °) or the form error from the basic angle. (GD&T angularity)

David DeLong · Jul 16, 2010

Re: Angularity

jfbock said:
Simple question I am having a hard time finding a concrete answer on.

When angularity is called out, should the angle it refers to always be a basic dimension? Wouldn't the angularity callout BE the tolerance for the angle.

I have a customer print that has angularity only as a callout (no form tolerance) and a regular (non-basic) angle callout. My understanding is this is not correct.

Appreciate any help.

Using both ASME Y14.5M-94 and now th3 2009 edition, the angle must be shown in a basic dimension. The tolerance in the feature control frame is tolerance for this angle. If the drawing reflects the angle without being a basic dimension, then the drawing is incorrect.

By the way, angles on surfaces in GD&T also include flatness while angles in holes include straightness.

Jim Wynne · Jul 16, 2010

jfbock said:
Simple question I am having a hard time finding a concrete answer on.

When angularity is called out, should the angle it refers to always be a basic dimension? Wouldn't the angularity callout BE the tolerance for the angle.

I have a customer print that has angularity only as a callout (no form tolerance) and a regular (non-basic) angle callout. My understanding is this is not correct.

Appreciate any help.

TP and David have answered the "basic" question, but I'll add that whenever you encounter ambiguous specifications it's best to ask the customer what the intent is. If there's no reference to any GD&T standard on the drawing, it means that the designer can use the symbols to mean whatever she wants them to. Even when the standard is referenced, designers will often demonstrate their failure to understand it.

Stijloor · Jul 16, 2010

Jim Wynne said:
TP and David have answered the "basic" question, but I'll add that whenever you encounter ambiguous specifications it's best to ask the customer what the intent is. If there's no reference to any GD&T standard on the drawing, it means that the designer can use the symbols to mean whatever she wants them to. Even when the standard is referenced, designers will often demonstrate their failure to understand it.

How true this is! I often see drawings with mixed symbols from 1982 and 1994 GD&T standards.. No standard reference in the title block, so it becomes pure guesswork...

Stijloor.

Angularity - When angularity is called out should it be to a basic dimension

jfbock

True Position

David DeLong

Jim Wynne

Stijloor

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