Flatness on a per unit basis

[Oaklandishh]

I am looking at a drawing made by a US company in 1975. I cant find a reference to any drawing standard.

there is a note regarding flatness that reads as follows:
"DEVIATION FROM VERT TO BE WITHIN .005 TOTAL FLATNESS. TOL FOR SURFACE [a bunch of surfaces] TO BE WITHIN .002 TOTAL (MAX .0002 IN/IN.)"

I am thinking this should be interpreted similar to how per unit flatness is specified in ASME-Y14.5M-2009 which I think is similar to the picture below where there are infinite .0002" apart 1"^2 flatness zones within the full parts .002" flatness zone:

Am I misunderstanding this?

 

[pylfrm]

Oaklandishh,

There's a lot going on in that note that's not very clear. "DEVIATION FROM VERT"? ".005 TOTAL FLATNESS"? ".002 TOTAL"? Perhaps it makes more sense in the context of the drawing.

For the flatness on unit basis, think a 1 inch diameter circle would be a more natural interpretation than a square. You won't have to worry about the diagonal being longer than 1 inch, or which way it points.

- pylfrm

 

[CheckerHater]

Well, the choice of terminology is clearly not the best.

I think "DEVIATION FROM VERT .005" is some form of parallelism, refined by overall flatness of .002 then further refined by flatness per unit of .0002.

"IN/IN" most likely represents square.

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