True Position of holes, without Diameter symbol in Control Box??

let me lay this out for you guys and gals the best I can:

I have Datum A wich is a inside Circle recessed into the top of the part. We will call this "Datum A"

I have another recessed circle on the bottom of the part. We will call this "Hole"

"Hole" has a dimension callout that reads as follows: Dia. 7.06"
[T.P./.010/A] Notice there's no Dia. Symbol in the Cntrl Frame

I have never seen this callout before without the Dia. Symbol in the control frame when in reference to a datum that is a circle or cylinder, have you?

If I run this with both features as Circles, I get a measurment of 0 (ZERO)

If I run this with both features as Cylinders, I get some actual numbers, but I don't know if they are correct.

If I run this with Datum A as a Cylinder and Hole as a Circle, I get 0(ZERO)

I am confused as to which way i am supposed to do this. Is the callout on the drawing messed up, or am I giving Pcdemon incorrect features to calc this dimension?

Any help would be greatly appreciated.

Sam

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REDWINGJ over 12 years ago

Per ASME Y14.5 the location tolerance zone applies to the entire length of the feature unless specified otherwise. This means that it is never proper per the standard to use only a circle to report position, you should always use a cylinder. For this very reason Xactmeasure will not let you report the position of a circle. Please be careful about giving incorrect advice.

So your saying that if datum_A on my part is only .060" thick and there are 30 holes spaced out over that plane Xactmeasure won't let me position them? With material that thin creating a cylinder is pretty much a time sink, both in programming and in execution. I've never NOT been able to report them with Xactmeasure.

I am aware of the standard but honestly with a touch probe the CMM is never truly measuring the entire length of a feature. Even with a scanning probe if that feature is not a thru hole you can't probe it right up to the surface it intersects. The point could be argued and in my opinion my information was not incorrect.
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REDWINGJ over 12 years ago

Per ASME Y14.5 the location tolerance zone applies to the entire length of the feature unless specified otherwise. This means that it is never proper per the standard to use only a circle to report position, you should always use a cylinder. For this very reason Xactmeasure will not let you report the position of a circle. Please be careful about giving incorrect advice.

So your saying that if datum_A on my part is only .060" thick and there are 30 holes spaced out over that plane Xactmeasure won't let me position them? With material that thin creating a cylinder is pretty much a time sink, both in programming and in execution. I've never NOT been able to report them with Xactmeasure.

I am aware of the standard but honestly with a touch probe the CMM is never truly measuring the entire length of a feature. Even with a scanning probe if that feature is not a thru hole you can't probe it right up to the surface it intersects. The point could be argued and in my opinion my information was not incorrect.
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