GD&T actual mating envelope
Mufaddal Rasheed 
What is the meaning of the term actual mating envelope in GD&T, a brief explainer
Actual mating envelope is a term which is generally used for feature of size in GD&T which are supposed mate in assembly. Like a shaft and hole
To understand actual mating envelope, take the example of this block with a hole.
This is the design (nominal)
Consider a part manufactured which is imperfect (not nominal)
Cut section view of the as is manufactured hole.
The hole is not perfectly cylindrical nor is it having an axis perpendicular to top surface
Now if we consider a perfect feature counterpart which can be inscribed so that it just contacts the surface at the highest points
So in this case a cylinder (perfect shape) inserted into the hole where it touch es the high points is shown
Actual mating envelope is a term that refers to a machined / manufactured part's feature of size “as is” condition.
Here is an example of a pin :
Consider the pin is manufactured as a curved form as shown .
The actual mating envelope will be a cylinder which is contacting the high points of the shaft in its manufactured shape which is shown in translucent purple .
The local size measured of the pin is called actual local size
The size of the envelope is called actual mating size for the feature of size.
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Categories: : GD & Tolerancing