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Dean said:I still wouldn't hesitate to apply position on a conical feature
Dean said:I would recommend that either profile of a surface or position (without the <FF> modifier) be used if (M) or (L) is the functional case for drafted features.
Dean said:For MMC or LMC, the functional case is that clearance/space must be available for MMC, or material must be present for LMC. Since the mating feature will not center itself within the considered feature the axis is not relevant (or not relevant enough) for these cases, the surface is the feature element that should be controlled, from a functional point of view.
3DDave said:I'm trying to figure out what problem FF fixes, so I thought this was a current draft; hence my interest in looking for it.
3DDave said:How different is that than any nominally circular/width feature that ends up made with a taper? The magic expanding plug stops at the narrow end and that's the UAME
Kedu said:Speaking about UAME and its definition, I would like to ask you if there is any support from Y14.5 point of view to drive an axis from a conical surface?
In other words, if a hole 10mm ±0.5 is made as 9.5mm at one end and 10.5mm on the other how reliable an axis could be driven from this "as made" hole?
I think it is not stable and UAME could not be repeated in a consistent way.
Kedu said:Why in your slot definition (this link allowing position at MMC (or LMC) is not an option? Or maybe it is an option?
Otherwise stated, could you have position at MMC or LMC for that 2D conical circular element or for that 2D width ?
Burunduk said:Why not? The only difference between a 3D width/cylindrical feature and a 2D width/circle is the number of cross-sections at which the single width/diameter dimension and tolerance that was specified applies. One cross-section versus an infinite number.
For a tapered feature, there is no unique MMC/LMC, there's a different value for every cross-section. Suppose that you perceive a conical taper to be produced at LMC. Offset it in the axial direction relative to some fixed reference, and you get what can be perceived as an MMC cone. That is because cone size depends on where you measure it.
Kedu said:So, then why if the full feature term <FF> is added to the conical feature's position along with draft minus or draft plus notation, the callout became invalid?
myself said:Why not? The only difference between a 3D width/cylindrical feature and a 2D width/circle is the number of cross-sections at which the single width/diameter dimension and tolerance that was specified applies. One cross-section versus an infinite number.
For a tapered feature, there is no unique MMC/LMC, there's a different value for every cross-section. Suppose that you perceive a conical taper to be produced at LMC. Offset it in the axial direction relative to some fixed reference, and you get what can be perceived as an MMC cone. That is because cone size depends on where you measure it.