GD&T question

[Dannyrl]

I get prints covered with basic(boxed) dimensions. Everything I read about GT&T says a bisic dimension should tie back to a feature control frame. i have many that doesn't. What tolerance should be applied? Title block tolerance? I get lots of different answers around here. I usually just give the measured and nominal and let the powers decide what tolerance they want to apply.
danny

[Jeffrey Lovely]

I use zero tolerance (basic dim) DIS Software will not show this as out
then report true pos
if true pos does not apply
use the general tol

[russ.griffith]

Doesn't that annoy the crap out of you when they do that. Send them a capability study with no tolerance for the features. That should get their attention.

[Paul Sarrach]

You don't do anything with them. You do not tolerance. DO NOT Baloon them. They do tie into at least on dimension, They are usally tied into something other than your basic ABC Datum Scheme. They want to get of of body position and use an alignment though something. Do you have a pic we can look at? What they are good for is letting you know you did the correct Alignment.

[Dannyrl]

I'll try to get a pic without having to put the whole print on here. almost every print I get has something dimensioned like that . Usually a hole with just basic dimensions and no GD&T. I think when they dimension it, they can't decide so they just put basic on everything.

[BSchwark]

Everyones print is a little different. Like you said report your measured value and let someone else figure it out. Try to find out what that person came up with and why, if you get the chance.
I do not know how much you know about GD&T? but you could have 1 feature control frame for 8 diameters (might not say 8 but implies 8 diameters) this could accout for as many as 16 basic dimensions. Or a profile of surface control frame could have several basic dimensions associated to it.


BS

[Dannyrl]

Yeah Most true position control frames will have 3X or 4X or whatever and I can account for all the holes, but the ones that get me just have a hole size and thats it. I've had several people here with more GD&T experience look, not find anything, and say I should just report the actual and nominal. Been doing that way ever since. I've gotten lots of useful info from these forums so I thought I would throw that question out there to see how other people handle it.

[dwade]

All of our work is automotive and some of the prints we get have no FCF tied to any specific feature but will use a block FCF back to a specific type of feature where there are too many to list each one indivually. Tf they gave a FCf for each feature on the drawing, it would clutter it up making it hard to read, so they simplify things buy doing it that way.

[T Miller]

some of our prints have a geneal note at bottom saying all basic dims are whatever teh tol they want

[J Temmen]

If you want a quick response from your "superiors" try reporting every basic with zero tolerance so you r report shows 80 - 90% out of tolerance, they should sit up and notice that.

[kyle lattenhauer]

I get a lot og GE prints like this and in the notes it refers to "GE applied practice" document which I then have to look up and get the tolerance. Often this document will say unless other wise specified....
Could that be the case with your prints?

[george frick]

seems to me like your missing something. every basic dim on the print should tie back to a fcf that specifies the tolerance whether it be true position,profile,etc. and those dims are tied into a set of datums somewhere on the print and part. either the print is in error or your not interpreting it correctly. i would definitely get an answer from engineering or the customer to find out exactly what is required so your can accurately measure and report it.

[Rick Coleman]

We get box car loads of drawings with a generic, unless otherwise specified chart covering dimensions. Use these first, then look for GD&T callouts for specific features.

[rangerboat72]

GD&T

At least your getting the [BASIC] dimensions...

Anymore all I get is FCF because the people designing the stuff do not understand how the tolerance in the FCF actually gets applied... They expect the programmer to find all of the "required" information in the 3D model. What about the companies that do not have the ability to use the 3D model in their CMM software and whatever happened to the drawing checkers? They totally removed that " CHECKED BY: " box from our 2D drawings.

I don't think I'm the only one that's having these types of issues, am I?

[Dannyrl]

Talked to one of the design engineers up north on a different problem today. while I had him on the phone I asked him. He said the same as I thought that it is SUPPOSED to tie back to a control frame. He admitted they make mistakes and said I should do just as I have been doing. Only report actual, nominal and deviation and let somebody else figure it out.
Imagine that!!!!