Unknown GD&T meaning.. help!

[GregS]

http://www.imagedump.com/index.cgi?p...id=20&warned=y

What does that a-b c-d mean? Ive never seen a dimension like that before. I apologize for the image hosting site if there is any bad words, its the only one I have an account to at work

[Paul Sarrach]

On your print it will have area's marked off as A B, they are the markers ( the start and stop points) from which they want to see the profile

[Tested]

These are just theo. points and you are to check the profile between them. i.e. profile from a to b and from c to d .

[GregS]

Thanks Paul

[ag1979]

For a profile call out like that it usually means that tolerance from ponit A to B and from C to D. Take a look to see if there are any markings along the profile, marked A, B, C, and D.

[kbotta]

Looks to me like you have a surface profile tolerance zone of 1mm that goes from pts A to B, and from pts C to D. See it all the time. They are using 1 FCF to control 2 'areas', or 'zones' on the drawing. (this way they do not have to identify with heavy chain lines, and add adittional FCF's. They have identified the area in which the tolerance aply's)...
kev

My spelling sucks...

[GregS]

The part is 80" long by 3" wide. They marked each corner of the rectangle with a letter A, B, C, D. So that definition fits perfectly. Thanks guys.

[Paul Sarrach]

Just a little info, these area's are usally critacal to the build. They are holding them tighter because there is a good chance for interferance with some part around it, possible where the mating part will be attached. So in that area you want to get it as close to NOM as possible. At the least let everyone no if it is eating up more than 75% of the tolerance, even 50%. It will CYA, and save you plenty of problems later

[GregS]

Just a little info, these area's are usally critacal to the build. They are holding them tighter because there is a good chance for interferance with some part around it, possible where the mating part will be attached. So in that area you want to get it as close to NOM as possible. At the least let everyone no if it is eating up more than 75% of the tolerance, even 50%. It will CYA, and save you plenty of problems later

With this customer I'd be willing to bet that there will be interference regardless of how we make the parts Engineers gogo!

[Paul Sarrach]

Just remember, put it in a form of email. Something you can track. Also see if you email show when they open it. Save it. This is just good advice about anything in question. And when you send it, find out from your boss who should be copied. Engineer memory gets pretty bad, if they know you cant produce evidence to the contrary