Can tolerance value bigger than nominal specification?

[skyline7509]

I encountered a dimension with 0.004 +0.007/-0.015 (units: inches), meaning the lower spec will be in negative value. Is this acceptable for tolerance value bigger than nominal spec? See attached picture.

Hope experts can enlighten me. Thanks

 

[drawoh]

skyline7509,

It looks weird to me. My interpretation of it is that the radius is allowed to be below the flat face. Does anybody have an alternate interpretation? The base purpose of standards like ASME Y14.5 is that dimension specifications must be precise.

It would be more logical if the dimension came from the flat face down below, but this may not be a good datum. Perhaps the flat face to the right is the datum, and they do not care (much) about the flat face to the left.

--
JHG

 

[monkeydog]

That looks like an assembly dimension, where the "pin" tip is allowed to be .011 past the flat flange or .011 under the flat flange.

 

[rothers]

The bigger question: is a dimension allowed to be negative ?

 

[CheckerHater]

Negative value could make more sense if dimension was given direction (origin):

"For every expert there is an equal and opposite expert"
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[chez311]

It definitely looks a little strange but I won't say its necessarily "illegal".

I agree with CH - regardless of the negative value or not, since one end of the dimension is tangent to the spherical "tip" the dimension origin symbol I think would be more appropriate and ensure the measurement is taken as the designer likely intends.

 

[dgallup]

I see no problem with it.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[mkcski]

I see no issue either. There is nothing "magic" about the .004 nominal value. The nose of the radius (or sphere) can be .011 beyond or .011 below the "square" face.

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