Flatness Call Out confusing me - What they are wanting and how to check it?

I am confused by the flatness call out on this drawing.

Would someone better than I please explain what they are wanting and how to check it?

Thanks, Caroline

Re: Flatness call out confusing me

Caroline:

Sorry but your file did not work out. Could not see it.

Re: Flatness call out confusing me

here it is in PDF form.

biker6977 said:

I am confused by the flatness call out on this drawing.

Would someone better than I please explain what they are wanting and how to check it?

Thanks, Caroline

Click to expand...

Hi Biker,

I think that it is max. 0,005 for the total surface but no more than 0,001 for each square inch (1x1) on that surface.

Cheers
Mr.happy

Thanks, that's what I was thinking but wasn't sure.

I agree with happy on this one.

I agree with the previous posters, the tolerance is 0.005 overall and 0.001 in any square inch. If you will be scanning that on a CMM one question you might want to ask your customer is what amount of overlapping of the squares are they expecting.

So how would you check it? On a granite surface plate with a 10ths indicator? No - I don't have a CMM with a probe.

silentrunning said:

So how would you check it? On a granite surface plate with a 10ths indicator? No - I don't have a CMM with a probe.

Click to expand...

You would need the indicator sticking through the surface plate, simply indicating the opposite side of the part to the surface plate would be measuring parallelism. The traditional method for flatness used 3 adjustable jacks but that is VERY slow.

Yep on a surface plate sit on three jig blocks with a 10th indi