That's the email I got upon entering the shop today. I was using a 1 x 10 styli for a part with 3-48 & 6-32 threaded holes. Just trying to get a decent location within tolerance of +/- .005. Now, the customer (we are the sub-contractor) is "coming in today with a cylindrical probe which will take more accurate hits on thread holes". I checked some of the postings in the forum and it looks like there's a lot involved and the results are sketchy.
A little off topic but why the heck hasn't GD&T become a required course for any manufacturing, quality or design engineering degree. I'm sure you all realize most of the people applying GD&T to the drawings we deal with on a daily basis have no idea what they are doing. I'm sure most of us have crack(ed) the code at some point and understand the intent and apply to what the intent of the designer wants to the best of our ability. I don't hesitate for 2 seconds to contact a customer when I find un applicable GD&T on a print. They need to know immediately what can and cannot be achieved.
A little off topic but why the heck hasn't GD&T become a required course for any manufacturing, quality or design engineering degree.
To be fair to most universities, GD&T is a fairly recent change in engineering thinking. I graduated two years ago now, the course was 4 years long, meaning that the course material was designed as little as 6 years ago and more likely more than that. I am sure if I was to start on an engineering degree now or next year you would see GD&T as part of the course. Unfortunately that means that you will be waiting perhaps 3 years or more before you start seeing lots of graduates who have been tought from the beginning on GD&T.
I have been in the aerospace industry for thirty years now and have used GD&T since I started, it is not something new. It was required from the start of my inspection career, I have tought classes internally for almost twenty years now.
A little off topic but why the heck hasn't GD&T become a required course for any manufacturing, quality or design engineering degree. I'm sure you all realize most of the people applying GD&T to the drawings we deal with on a daily basis have no idea what they are doing. I'm sure most of us have crack(ed) the code at some point and understand the intent and apply to what the intent of the designer wants to the best of our ability. I don't hesitate for 2 seconds to contact a customer when I find un applicable GD&T on a print. They need to know immediately what can and cannot be achieved.
Technically it is required, but not as such. GD&T is nothing more than Pythagorean Theorem on steroids. All the calculations are done with a^2+b^2=c^2. The differences are that Pythagorean Theorem deals with 2 axis and radial calculation zone, while GD&T deals with 3 axis and diametric calculation zone. Just have to put 2 and 2 together.
You would not believe how many times I've had to explain why the reported TP value is double the straight line deviation. The more worrying part is whom I've had to (repeatedly) explain it to, whom they work for and what they work on
This isn't one specific person by the way, many many people in many different industries.
But is it still not accurate. what did he say above?
"I would never just use a ruby ball inside a threaded hole because the ball will fall in between the threads on one side of the hole while it may hit the "peak" of the thread on the other side of the hole."
