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True Position in 3 axis???

1CMM4ME
Ok, I have read the post regarding this so called argument that my boss and I got into today. He told me that you cannot measure true position in 3 axis, as I told him he was wrong. I know it depends on the way the FCF calls it out, but I tried to explain to him that it is possible to measure TP in 3 axis.
I have seen the formulas, so I know it's possible. I just wish I could get one of you gurus to reply back explaining that it is possible and why. I see the picture but he does not. I do not like to get into pissing matches with upper management, but I have learned a h**ll of alot from you guys, and I know this is possible. So if one of you fine gentleman can back me up on this, I would very much appreciate it. Thank you very much.
Now I am going to get a cold beer.Smiley
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  • OK. My illustration shows the FCF attached to the features and is called bi-directional (single axis) on page 60 of my handbook. Perhaps it is an incorrect depiction. I will get a picture of it and post it.

    Anyhow, when I was trained in GD&T (professional certificate course) one of the main rules was that EVERY Basic Dimension HAD to have a FCF associated with it or it was incorrect / undefined / uncontrolled etc. In the event that you have THREE Basic Dimensions locating a Diametric TP (Two Axis) you inevitably have an undefined / incomplete / uncontrolled Basic Dimension as ONLY two of them are significant. Which ones are significant and which ones are undefined are usually easy to discern. Sometimes they are not. I am curious as to what the people on here do when it is unclear which Dims are reported. One good example is when the feature is on a 45° angle. Which Axis is then used? Becomes ambiguous and you CANNOT use all three. In those cases I call the BASIC Dims as SET (perfect) and report the TP normal to the surface it is in. None of the dims on the print show up in the result. But, this does NOT truly satisfy the rules of GD&T - specifically that every BASIC Dimension must have an associated FCF. So, I deem it illegal as it violates the princinples of GD&T. Does that make sense?
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  • OK. My illustration shows the FCF attached to the features and is called bi-directional (single axis) on page 60 of my handbook. Perhaps it is an incorrect depiction. I will get a picture of it and post it.

    Anyhow, when I was trained in GD&T (professional certificate course) one of the main rules was that EVERY Basic Dimension HAD to have a FCF associated with it or it was incorrect / undefined / uncontrolled etc. In the event that you have THREE Basic Dimensions locating a Diametric TP (Two Axis) you inevitably have an undefined / incomplete / uncontrolled Basic Dimension as ONLY two of them are significant. Which ones are significant and which ones are undefined are usually easy to discern. Sometimes they are not. I am curious as to what the people on here do when it is unclear which Dims are reported. One good example is when the feature is on a 45° angle. Which Axis is then used? Becomes ambiguous and you CANNOT use all three. In those cases I call the BASIC Dims as SET (perfect) and report the TP normal to the surface it is in. None of the dims on the print show up in the result. But, this does NOT truly satisfy the rules of GD&T - specifically that every BASIC Dimension must have an associated FCF. So, I deem it illegal as it violates the princinples of GD&T. Does that make sense?
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