I'm arriving a little late to this discussion but have read all of your arguments. I'm glad to see I'm not the only one who has had heated discussions on the topic of profile.

First, let me say that I agree entirely with Tom. The profile callout is stated as a tolerance "zone", this zone must be split up for measurement purposes (bi-lateral), but to compare apples to apples you must state the final measurement result as a "zone". The reported "zone" is twice the maximum deviation from the nominal surface (ie. points ranging from +0.6 to -0.1 create a zone of 1.2). Agreeably the reported result of 1.2 doesn't tell you how to fix the feature, this is where the separate point data comes into play.

Basically, my advise would be, if the profile is within tolerance, the single profile result is sufficient. If the profile falls out of tolerance, separate point data will be required. It has been my experience that the people reviewing inspection results don't spend a lot of time on the dimensions which fall within tolerance.

I'm sure this topic will continue to be a source of argument since the ANSI Y14.5M explanation of profile does not specifically cover the reporting of the results but only the interpretation of the callouts.

Bill Reilly
Quality/Technical Manager
Quality Inspection Technologies