Unsure about callout on position

[[Ca...]]

When to use bore pattern vs feature for position? In this case I get different results when using on over the other.

 

 

 

Edited 11 hours ago

[[Ri...]]

Be default I would assume it's a pattern. If do not measure it as a pattern, and just (8) separate Positions, you are only measuring the Perpendicularity of the Cylinder to Datum A. 

[[Ze...]]

The callout is a pattern of 8 which must all be best fit to A. So, use the bore pattern with both Rotation and Translation checked and use View Tolerance under Best Fit method to use the MMC and proper fitting based on a hard gage. 

[[Ca...]]

So any position that calls for 2x or more is a pattern then and cannot be position individually?

Edited 11 hours ago

[[Ze...]]

Not necessarily. It depends on how many degrees of freedom are constrained on the features. If a pattern of holes is fully constrained to A|B|C, for example, then checking them individually to A|B|C or as a pattern to A|B|C will give the same results, as there is no best fitting on fully constrained features. 

[[Ri...]]

That's kind of a loaded question because if MMB/LMB is invoked then it would matter if they are evaluated together or not. And then there are the Composite Tolerance scenarios. 

[[Ca...]]

That is very helpful! 

[[Ca...]]

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Do you use bore pattern for composite and single segment position?

Edited 10 hours ago

[[Ky...]]

You can, but it depends on the exact callout whether or not you absolutely need. The primary use case for the best fit bore pattern is to move patterns together relative the the DRF rather than individually.