Is Datum B understood to be a centerline?

[Barnon]

I'm trying to reference Datum B which is the centerline of a cylindrical surface originating on a previous sheet. I see examples similar to this where the Datum is actually the 33.57 dimension (see example at bottom).

 

[mkcski]

In my opinion placing the "DATUM AXIS B" note on the datum axis on another sheet of the drawing is meaningless. The reader still does not know which feature establishes the datum. There could be numerous coaxial features that could be selected as the datum feature. If the note is applied it must direct the reader to the sheet where the datum feature is identified (with the symbol) so there is no doubt which specific feature is the datum feature.



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