BASIC DIMENSIONS USE G D &T TOLERANCING, THE QUESTION IS I HAVE BASIC DIMENSIONS COMING FROM X & Y AXIS. AM I SUPPOSED TO "CUT" THE TOLERANCE IN HALF WHEN DIMENSIONING THE BASIC DIMENSION? example X AND Y ARE BOTH [2.077] THE TRUE POSITION CALLOUT IS ALLOWING UP TO .015 SHOULD I USE .0075 FOR X AND .0075 FOR MY Y TOLERANCE?
You obviously have no idea about how basic dimensions work (or even that there is a button marked 'caps lock' on your keyboard...), so I'll give you the advice that I nearly always give those who either can't or don't understand the mathematical theory behind it:
Take your "true position" value, and divide by 1/3 for the safe amount of tolerance in either direction. This will in effect be over-tolerancing the position, but will keep even the least experienced operator safe from creating scrap.
You obviously have no idea about how basic dimensions work (or even that there is a button marked 'caps lock' on your keyboard...), so I'll give you the advice that I nearly always give those who either can't or don't understand the mathematical theory behind it:
Take your "true position" value, and divide by 1/3 for the safe amount of tolerance in either direction. This will in effect be over-tolerancing the position, but will keep even the least experienced operator safe from creating scrap.
You realize that this forum is for people to come and ask questions without fear of being harrased or embarrased. There are individuals on hear from ALL experience levels and in ALL types of industries. I work with degreed engineers who do not fully understand GD&T and how basic dimensions work. Putting someone down for asking a question is just bad form and typically leads to the admins getting involved. I would offer a bit of advice if you choose to be a part of this forum. Be respectful and mindful that not everyone is as knowledgable as you think you are. Just my .02
You realize that this forum is for people to come and ask questions without fear of being harrased or embarrased. There are individuals on hear from ALL experience levels and in ALL types of industries. I work with degreed engineers who do not fully understand GD&T and how basic dimensions work. Putting someone down for asking a question is just bad form and typically leads to the admins getting involved. I would offer a bit of advice if you choose to be a part of this forum. Be respectful and mindful that not everyone is as knowledgable as you think you are. Just my .02
I'm sorry if this poster has hit a "raw nerve", but I fail to see how anybody can call themselves either a "QC person" or especially an "engineer" and NOT be able to understand at least the most basic meaning of positional tolerancing, yet I meet people like this nearly every day (one was my former quality MANAGER, even!).
I realize that there are some who can't do long division, much less understand the basics of Pythagorean trigonometry, and for those people, there are numerous calculator programs, online applications, and the old, trusty wall charts to get you through this kind of quandary. There is even a very succinct definition on Wikipedia (
http://en.wikipedia.org/wiki/Geometric_dimensioning_and_tolerancing) for those who at least want to learn this, the single most basic aspect of modern tolerancing.
I notice that this poster has asked questions before pertaining to actually programming a CMM, which says to me that he is, in fact, employed as a QC person, yet he knows almost nothing about GD&T, which troubles me. So, I apologize for pointing out the blatantly obvious, in a less-than-kind manner, but let me advise the poster to get himself a good book, because his entire business revolves around something that he seems to know very little about.
I'm sorry if this poster has hit a "raw nerve", but I fail to see how anybody can call themselves either a "QC person" or especially an "engineer" and NOT be able to understand at least the most basic meaning of positional tolerancing, yet I meet people like this nearly every day (one was my former quality MANAGER, even!).
I realize that there are some who can't do long division, much less understand the basics of Pythagorean trigonometry, and for those people, there are numerous calculator programs, online applications, and the old, trusty wall charts to get you through this kind of quandary. There is even a very succinct definition on Wikipedia ( http://en.wikipedia.org/wiki/Geometric_dimensioning_and_tolerancing) for those who at least want to learn this, the single most basic aspect of modern tolerancing.
I notice that this poster has asked questions before pertaining to actually programming a CMM, which says to me that he is, in fact, employed as a QC person, yet he knows almost nothing about GD&T, which troubles me. So, I apologize for pointing out the blatantly obvious, in a less-than-kind manner, but let me advise the poster to get himself a good book, because his entire business revolves around something that he seems to know very little about.
Or he was thrown into it with no training. There's no harm in helping people out, there is harm in being unruly.
You realize that this forum is for people to come and ask questions without fear of being harrased or embarrased. There are individuals on hear from ALL experience levels and in ALL types of industries. I work with degreed engineers who do not fully understand GD&T and how basic dimensions work. Putting someone down for asking a question is just bad form and typically leads to the admins getting involved. I would offer a bit of advice if you choose to be a part of this forum. Be respectful and mindful that not everyone is as knowledgable as you think you are. Just my .02
+1,000,000
There is a correct mathematical formula for calculating true position RFS. Simple and quick. Square deviation of X and Y, add them together, take the square root of that number and multiply that by 2. That would be the formula you give your operator.
