I have a bore that is Datum B. It has a perpendicularity callout to Datum A, which is a flat surface. So, I have to measure it as a cylinder. I have another bore that has a circular runout callout to AB. So do I have to measure B again as a circle? Because I would have to assign that as another datum to build the feature control frame. But if I just use B as a cylinder, then wouldn't it be measuring total runout and give me a different result than circular runout?
I don't recall if Xact "slices" the cylinder IF the toleranced feature IS a cylinder and the tolerance is single runout. Maybe
neil.challinor can chime in to fill in the blanks.
Legacy does not do this, so if you choose a cylinder for a single runout, legacy will give you the worst runout over the length of the cylinder = total runout. Here, you as the operator must choose circles as the toleranced feature since the software isn't taking the source feature type into consideration. This means that you must MEASURE them as circles and evaluate them as circles.
GeoTol however, works fine with single runout with a cylinder as toleranced feature since the invisible helping hand will slice the cylinder (recommended to measure the cylinder with concentric circles) and evaluate these sliced circles and report the worst runout of these circles.
I corrected my post above. I failed to mention that the old programs were measuring the circular runout of a bore or turn by simply measuring them as one SINGLE circle. If I understand it, that's not correct since it's only taking a single "slice" of the cylinder. This is what I'm afraid to bring up since it likely means that they were sending non-conforming parts for years and I, as a rookie, have to call them out for it.
I corrected my post above. I failed to mention that the old programs were measuring the circular runout of a bore or turn by simply measuring them as one SINGLE circle. If I understand it, that's not correct since it's only taking a single "slice" of the cylinder. This is what I'm afraid to bring up since it likely means that they were sending non-conforming parts for years and I, as a rookie, have to call them out for it.
