How do you control profile of a surface?

[km4512]

Suppose you have a square shaped object and have a profile of a surface callout on it of 0.5... on a gage how would you control this? Basically, I'm asking how you would design a gage to check for the profile control?

Anyone have any examples of such gages that control profile?

 

[KENAT]

Wouldn't you have a go gage & no go gage in a similar manner to with a round feature?

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[km4512]

I do not understand? But I'm talking about a square box?

 

[KENAT]

Uh-Huh.

I'd have go & no go gages just like for a round item but they would be square.

One would simulate MMC, the other LMC.

Do you understand profile tolerance itself?

What standards are you working to/are the drawings to? It shouldn't make much difference but just in case.

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[ptruitt]

It depends on your requirements. If no one's life depends on this block, measure it with a single-axis device like a dial caliper. A pair of rectangular plug gages would be a bit better. If it is high-end, have a look (page 4) at what one supplier is doing:


Peter Truitt
Minnesota

 

[pmarc]

km4512,

If you think of a hard gage, you are not able to do this. And it is not a matter of whether the hole is round or square.

Profile of surface is two-sided requirement, so it has two boundaries that describe feature in its maximum material condition (MMC) and in its least material condition (LMC). You could build a gage that would check MMC of a feature, but in the same time checking LMC with hard gaging is simply impossible, because LMC boundary is 'inside' the material of a part.

 

[km4512]

Thanks for your response guys.