Calculate Diametric Tolerance

[ksterling15]

I have some tolerances that were calculated through a CETOL study in the X and Z directions. I need to convert these to diametric tolerances. I am not sure how to do this.

Nut 1 tolerance is Z=81+/-1.05 & X=213.4+/-1.26

Nut 2 tolerance is Z=81+/-0.938 & X=103.4+/-1.26

Nut 3 tolerance is Z=81+/-0.972 & X=103.4+/-1.147

Nut 4 tolerance is Z=81+/-0.953 & X=103.4+/-1.146

Could someone help me convert these to diametric tolerances, please?

 

[Wuzhee]

Those plus-minus tolerances create a rectangle. Calculate rectangle area in excel. Substitute area and calculate diameter of circle.
Is this correct for you?

 

[drawoh]

Wuzhee,

That is not correct. If you have calculated a square tolerance zone based on screw clearances, your positional tolerance diameter is 2[×]sqrt(2[×][±]tol[sup]2[/sup]). The positional tolerance would have been way easier to calculate in the first place.

The OP has somehow worked out rectangular (i.e., not square) tolerance zones. Unless we understand the requirement, these do not convert to positional tolerances.

--
JHG

 

[ksterling15]

What do you mean "understand the requirement"?

 

[drawoh]

ksterling15,

We don't know what was analyzed. If I have holes located from a sheet metal edge in one direction, and a bend in the other, I have a rectangular tolerance. It does not convert to a diametral positional tolerance. I can be accurate in one direction, and sloppy in the other. Is this the OP's requirement?

--
JHG