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Gd&t

Avsfan135

Cast Iron
Joined
Jan 19, 2011
Location
Fort Collins, Colorado
Who uses it?

our shop doesn't

Im trying to find a job and have never used GD&T and was wondering how important it is to you that your machinists know how to use and read it.

And how many shops are using it
 
Almost ALL aerospace prints are done up with G D and T. I suggest you learn it. It is good to know, even if you don't use it every day. Lowell puts out a nice pocket reference, though a little hard to wrap your head around the first time or two:

A Pocket Guide to Geo-Metrics III: Dimensioning and Tolerancing, Inch Version

Other manufacturing industries also use Geo. Dim. and Tol. I would think it will become more widespread, although I use it far less than I used to when I worked with Allied Signal Aerospace and Fluids prints.

WINGS FAN!
 
I think your question is a good one. But I think it depends upon what type of shop you are trying to get on with, how interested are you in learning new things, do you run manual or cnc equipment, are you responsible for setups, and do you do any programming or do you hope to, and last of all, are you responsible for inspecting the parts?

From what I have seen, GD&T is not used very widely. I think the biggest reason is that a lot of the people making drawings don't understand it so they do not dimension that way. Probably the larger the company, the more likely they are to use GD&T.

I think getting some knowledge of GD&T is important. My thoughts are that if you can't read the print, you are basically guessing at how to make the part, and you also can't tell if what you made is correct. Basically the prints are the designers way of attempting to communicate with the machinist. If you can't read them, it is a problem.

I do my own designs and machining. If I had something critical, and needed to sub it out, i would probably use GD&T. It is great way to communicate in much more detail than with regular dimensioning.
 
We use GD&T frequently. Unless the part is really simple or quick and dirty lab tooling, the drawings I get will have GD&T on them.

It would be worth learning to interpret the symbols and how to decipher control frames, but you don't need to be an expert in it. I've got the full book that Aerodark recommends and it's fairly easy to understand. I've also got a small pocket reference I keep in my tool box to remind me of what the symbols mean. GD&T can be confusing and easy to misuse from what I've seen.

Our company has more of an aerospace background, so that may be why we use it. But when ever we send something out that can't be done in house it will usually have GD&T all over it to make sure to remove as much ambiguity as possible (or create more confusion).

MO
 
gd&t

almost all newly generated drawings have gd&t on them it is standard procedure in engineering schools to teach this
it is truly remarkable as it lets machinists know exactly what the engineer is thinking
change is good
 
almost all newly generated drawings have gd&t on them it is standard procedure in engineering schools to teach this
it is truly remarkable as it lets machinists know exactly what the engineer is thinking
change is good

I'm an engineering student at RPI in New York. I have a friend at WPI and one at MIT. We're all studying mechanical, none of the three of us have been taught GD&T as a required subject. I had to learn it on my own.

I certainly agree with the "change is good" comment with regards to GD&T!

Henry
 
reply

went to trade school then community college for engineering both schools not only taught us gdt extensively i believe it was required cirriculum i am personally appauled that theese top notch universities are not teaching what are considered to be our most gifted engineering students this most valuable mechanical drawing asset
 
The last outfit I worked for-it was an aircraft OEM-transitioned to ANSI Y-14.5 in the early part of my stay there. Once you learned the language (and the draftsman did, too), it took much ambiguity out of the drawings. I got so I preferred running prototype parts, which were dim'd IAW ANSI specs vs tooling or gaging, which weren't. I wasn't a gd&t expert, didn't need to be; what I didn't commonly use could be looked up, and what I did need was learned on the fly.
 
if you learned gd&t it will change your perception on the tolerance given on the drawing ...you will know how important the part is...
 








 
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