GD&T Positional tolerances

[rwild]

Can you have a positional tolerance feature control frame on a hole without referance to any datums? If this is a correct way of dimensioning, then what is it controling? Perpindicularity, hole to hole, something else?

 

[KENAT]

forum1103 might get you more answers.

I had a quick look in 14.5 and a simple answer didn't jump out at me, so maybe I'll leave this one to others unless I get a bolt of inspiration.

I'd normally expect at least a single datum called out to give perpendicularity but like I said, didn't find a concise explanation in a quick flick through section 5.

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(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[ewh]

Kenat is right pointing you to the other forum.
As to your question, I see no purpose of a positional tolerance unless it is relative to something.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[Troy2601]

I agree with the above posts, there is no reason to put a positional tolerance on a hole with no datum refrence unless the hole itself is the datum.