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Do I have the correct Idea for Position tolerance

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Radius1

Mechanical
Jan 13, 2021
37
If finding the maximum x direction the position is allowed to deviate, then it would simply be 1/2 of the position tolerance of 0.2 = 0.1, as shown in circle 3?

The y component, or distance from the B datum would remain unchanged, correct?

Pos_Tol_twwoh1.png
 
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You have a MMC so if the hole is larger than the minimum size tolerance the position tolerance will be more than 0.2. (This is usually the design intent so I'm not saying it's wrong, just making sure you know.)
The allowed distance from the B datum is also allowed to change based on the position tolerance. (This is also visible in your coordinates since y changes from 1.5 to 1.6.)
 
Steven_D_P has a good point about the MMC, but I suspect there is more than that not taken into account based on how the possible results were drawn, and: "The y component, or distance from the B datum would remain unchanged, correct?"

Even assuming the hole was produced at the minimum mating size and 0.2 is all the tolerance available, the maximum allowed X deviation is indeed 0.1 from true position (just like in any direction), but if X=2.60 occurs, that doesn't mean the entire hole axis must remain at Y=1.50 like in your drawn case #3. The axis will not be perfectly perpendicular to datum A, and if one end of it is at X=2.60 the other end may be anywhere within the tolerance zone cylinder, including the extremes of Y=1.40 and Y=1.60. Think of it 3-dimensionally, not as a point within a two-dimensional circle.
 
Thanks Burunduk,

Something along the lines of what this image shows?

3D_pos_fscmz9.png
 
Yes, the total perpendicularity tolerance w.r.t. datum A in the worst case is 0.2 + the size tolerance of the hole.
 
Thank you Steven_D_P,

Yes, I was unsure about the MMC, good point.
 
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