GDT Tolerance Symbols & Notations

[BrittToolEngineer]

I have a need to use GDT symbols, and I also have a need to specify a range that is not symmetric (so-to-speak). Can you indicate in the boxes a +.002 -.006?

Thanks,

Brent

 

[BrittToolEngineer]

Also, the feature symbol I need is profile

 

[JNieman]

Yes, that's exactly how unilateral or unequal tolerancing works. I'm assuming you're using ASME for convenience... I have no idea about ISO. I know there is similar, but don't know the specifics. Hopefully this gets you close enough, if you are referencing ISO standards.

3.3.22 Unequally Disposed Profile Symbol
This symbol indicates a unilateral or unequally disposed
profile tolerance. The symbol shall be placed
in the feature control frame following the tolerance
value as shown in Figs. 3-11 and 8-1 through 8-3 and
para. 8.3.1.2.

See attached screenshot

 

[Xwheelguy]

So you're wanting a profile of a surface with an unequal bilateral tolerance? By ASME, that would be using the circled U. The number that follows the circled U indicates the amount of profile tolerance that is in the direction that would allow additional material to be added to the true profile.

NX9_BILATERAL_PROFILE.PNG

Tim Flater
NX Designer
NX 9.0.2.5 Win7 Enterprise x64 SP1
Intel Core i7 2.5GHz 16GB RAM
4GB NVIDIA Quadro K3100M

 

[BrittToolEngineer]

Awesome, thank you gentlemen!

 

[Xwheelguy]

It's important to understand that in my pictured example the TOTAL tolerance is 0.1 & the 0.06 is ONLY the amount the nominal (as modeled) profile can move OUTWARD (in this case, outward is adding material). That means the inward tolerance is ONLY 0.04 from nominal. It's a little deceiving.

Tim Flater
NX Designer
NX 9.0.2.5 Win7 Enterprise x64 SP1
Intel Core i7 2.5GHz 16GB RAM
4GB NVIDIA Quadro K3100M