This is a diametric tolerance.  The center of the hole must fall within a .005 diameter circle of it's true position in relation to the X and Y datum.

Don Vischulis

-----Original Message-----
>From: Donald Kyle <[log in to unmask]>
>Sent: Jul 10, 2006 10:09 AM
>To: [log in to unmask]
>Subject: [TN] Geometric Tolerance
>
>We are having a little debate here as to the interpretation of a
>Geometric statement evolving the tolerance of holes on a PCB.
>
>The geometric statement reads from left to right:
>Position (symbol)
>Diameter (symbol)
>.005 (tolerance)
>X (datum)
>Y (datum)
>
>Some say that this statement means a positional tolerance zone within a circle.
>
>Others say that this is just another way of stating a bilateral
>tolerance zone within a square.
>
>How do you interpret this?
>
>If you have IPC-D-325A you can read about this on page 28 and
>appendix B for more information.
>
>Because I don't know how to insert a geometric symbol for POSITION
>and DIAMETER you will need to use your imagination here.
>
>  Geometric      Geometric       Tolerance       Datum
>  Symbol for     Symbol for                      Reference
>  Position       Diameter
>        __             __                   .005                 X      Y
>
>
>Thanks for your time
>
>
>Donald Kyle C.I.D.+
>
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