I run into this problem all the time with AS9102 reports. Our customers want the basic bubbled, but then they complain when a basic '"fails" block tolerance.
Although we learned block tolerances in school, I was blessed to cut my teeth in shops where the bulk of the main customer's drawings did not contain block tolerances. Whether toleranced or basic, all of the dimensions in the drawing views fully defined their drawings. I now understand how freeing this was, because I see so many people in the industry married to the concept of block tolerances and "trickle down" concepts related to them, like what you are encountering. So much extra effort and fuss could be avoided if people freed themselves of these phantom block tolerances that exist only in their minds.
I would like to emphasize that even though the Y14.45 is a new standard, what a metrologist should report is NOT new. If they truly know GD&T, they should know what to report even without this new standard. Unfortunately, the industry is full of people who think they know GD&T but have no idea that they actually do not know GD&T. One very classical example I can give is reporting a feature of size: How many of you know that you have to report 2 values? One for the actual mating envelope and one for the actual local size. Another note is that you can not measure a BASIC dimension, as it is not possible. You have to imagine a very bad part in 3D and try to think what you are really trying to measure to see that. The only +/- dimensions on your drawing should be the features of size, including the general tolerances! +/- general tolerances (length and/or angle) are ambiguous at best.
Ugh, I know what you mean. If they want that information, the drawing should be prepared in some other way. The whole point of the system is that there is one drawing for everyone, not an engineers drawing and then a totally different thing for inspection.
Hi @R. Dean Odell, thanks for this great information, could you share us from your expertise what is the differences, Reference, typical dimension -indicated in brackets- ( ) vs Basic Dimensions? Thanks!!
Great explanation!
Thanks!
I run into this problem all the time with AS9102 reports. Our customers want the basic bubbled, but then they complain when a basic '"fails" block tolerance.
Although we learned block tolerances in school, I was blessed to cut my teeth in shops where the bulk of the main customer's drawings did not contain block tolerances. Whether toleranced or basic, all of the dimensions in the drawing views fully defined their drawings. I now understand how freeing this was, because I see so many people in the industry married to the concept of block tolerances and "trickle down" concepts related to them, like what you are encountering. So much extra effort and fuss could be avoided if people freed themselves of these phantom block tolerances that exist only in their minds.
I would like to emphasize that even though the Y14.45 is a new standard, what a metrologist should report is NOT new. If they truly know GD&T, they should know what to report even without this new standard. Unfortunately, the industry is full of people who think they know GD&T but have no idea that they actually do not know GD&T. One very classical example I can give is reporting a feature of size: How many of you know that you have to report 2 values? One for the actual mating envelope and one for the actual local size.
Another note is that you can not measure a BASIC dimension, as it is not possible. You have to imagine a very bad part in 3D and try to think what you are really trying to measure to see that. The only +/- dimensions on your drawing should be the features of size, including the general tolerances! +/- general tolerances (length and/or angle) are ambiguous at best.
When doing FAI's customer always wants basic dimensions reported. Wish they would get with the times.
Ugh, I know what you mean. If they want that information, the drawing should be prepared in some other way. The whole point of the system is that there is one drawing for everyone, not an engineers drawing and then a totally different thing for inspection.
@@RDeanOdell you're doing a great job of spreading the good word.
Hi @R. Dean Odell, thanks for this great information, could you share us from your expertise what is the differences, Reference, typical dimension -indicated in brackets- ( ) vs Basic Dimensions?
Thanks!!
🙏🙏
💔 ρ尺ｏΜ𝐎ᔕᗰ