GN and GX on OD

[[Ed...]]

Hello everyone,
Customer want to see GN and GX, like in attached file.
Can someone explain to me what is the meaning of GX for this OD? what does customer will benefit from this dimension? What it will show to him?
Always thought that GX is for ID (will show if counterpart can fit in) and GN is for OD (will show if it will fit into something)

Ekrānuzņēmums 2023-03-17 122617.jpg

[[Mi...]]

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We have parts for GM and Ford where the diameters are interference fit in their assembly, they have pins pressed in. We have to do both because that's what the customer does when they evaluate parts for failing pressing force.

Doesn't look like that's what the reason will be on that part, but it's just an idea.

[[Ri...]]

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Here is a breakdown of the different evaluations and what they mean.

While it is not common to evaluate both the GN and GX on a diameter, it is not completely uncommon.

I've seen it more commonly used in the automotive world for cam phasers, where there is a rotor that spins inside of a housing to control the cam timing. They control both because while yes you want to make sure the two fit together properly, you also want them to not low/high spots that cause leakage as cam phasers are completely controlled with oil pressure. The tighter the fit and function, the better performance/efficiency.

[[Je...]]

Is this an ISO-drawing?
Then GN is for upper tolerance, GX for lower tolerance (EN ISO 14405-1:2016, have a look at 6.2.2).

[[Ma...]]

So principle of envelope?

[[Da...]]

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Similar, but more strict requirement.