# Position of a milled hex - Print Callout

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#### echoone

I am wondering if my interpretation on this call out is correct. Please see attachment. Is it stating that the milled hex surfaces are to be between two parallel planes that are .010 apart relative to datums B and A?

#### Attachments

• hex button (2).pdf
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#### ncwalker

Yes. And don't forget position has a built in perpendicularity. Which means this is true at any depth of the hex pocket.

Also, it is a crappy tolerance.

1 - the "width" callout of the tolerance zone of .010 is redundant with the true position.
2 - the diameter is totally wrong, it's not a diameter.

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#### echoone

Thank you, for your help. Should it have been called out with a .371 basic? Secondly I was engaged in a debate with production floor. They stated that because of the diameter symbol the .010 position only applied to the hex that is tangent point to a constructed diameter.

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#### ncwalker

The problem is that position, while a valid control, may confuse people because they can't grasp how to apply it. It actually defines a cylindrical tolerance shell AT the diameter. But the simplest way to interpret it is is as a cylinder on the center with a diameter of the true position callout. This makes people think "round." But true position can be applied to any shape.

If it were me, I would have either gone from the center of the hex to the midpoint of the side OR the width across the flats and controlled it with symmetry. Then marked it 3X to cover the other flats (or 6X if I chose the radius method).

To your shop floor guys - ask them this ..... If the control only controls the tangent points of the flats, then what, exactly, controls the corners?

(In other words, they are wrong. The entire shape is controlled. But again, the callout is just implemented poorly).