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Basic dimension question

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SeasonLee

SeasonLee

Mechanical
Joined
Sep 15, 2008
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918
Location
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Hi All:

A simple question of basic dimension, when we calculate the position we need to measure the actual dimension 2X .185 as shown on the attached print, it’s a true position of the feature (although I know there is a basic angle 2X 50°), shall we change it to basic dimension?

Thanks for your inputs

SeasonLee
 
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Which standard are you working to, ASME or ISO? If ASME, then your position callout is at least suspect. I think you want to control location of small two flat portions of the bottom feature and not something which is in a middle of .185 distance.

My proposal would be to switch .185 to basic, show 2 of them on both sides of the part and apply two separate profile of surface callouts to both flat surfaces.
 
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I am with pmarc, I would use profile and move the leader to the surface, if referencing ASME. Even if using ISO, I would move the position leader to the surface of the tab, as for the for mentioned profile tolerance.
Frank
 
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Thanks for your comments, pmarc.

The print is per ASME standard, I agree surface profile control is better than position.

SeasonLee
 
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1) No there is no basic dinension to establish the TP of the centerplane from datum "A"(illegal).
2) If you intend to locate the centerplane the dimension should relfect that intent (bad form).
Frank
 
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SeasonLee,
Didn't you post this sketch or similar some time ago here and the same question was already answered?
 
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You are right, pmarc. this sketch posted at 3-20-12, how come I forgot it in a short time, sorry about that.

SeasonLee
 
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Yesterday, I got a different picture than this one.
Frank
 
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