GD&T Question, ISO

[[Mi...]]

I've been asked to assist a sister facility in a different country, this drawing is ISO. I'm completely unfamiliar with ISO. What's not shown in that drawing is that hub is stepped.

Datum B would be the 85mm diameter, which is the larger step at the base of the hub.

What is Datum D? I have some guesses. It looks like it might be specifically talking about a line segment along -B-. It only calls out one on the drawing.

Then item 8, the symmetry of B, parallel to D?
Is it this simple? Done a number of times around the hub?

[[Ma...]]

This is so confusing.

8 B|Sym - this should tell you direction of tolerance band for parallelism. But i was thinking, that it sould be parallelism or perpendicularity sign - not symmetry.

Base D should be only point - center of circle and base B should be center of cylinder anyway.

Edit - seems like base D is compound of points

[[ni...]]

Hi,
not anderstand your drawing, but for item 8, the interpretation is the opposite : item 8 as to be parallel to D "including" B (I don't have ISO 1101 in english, sorry)

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[[Mi...]]

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Okay so then is this a case of poor drawing resolution because stepped end of the hub which has a diameter of 84.5mm(0.5mm smaller)? 7,8,9 are actually referring to that, not B.

That starts to make more sense if that's the case... I think.

This is a cut of the model that actually shows the step.

[[Da...]]

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One would expect to find the lenght of datum feature D (a line) specified. Or to get details about counter part.

[[ni...]]

Hi,

I don't figure what D could be. I see on the drawing partial Datum d1 , maybe you have to inquire about other partial datum (d2-d3 ...)

have a good day

[[Ri...]]

Hope this helps

Drawing Question.PNG

[[Mi...]]

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Thank you! That confirms what I ended up finding. Not being well versed in ISO those "Intersection plane indicators" are a bit confusing to me. Trying to get the management to buy the standard.

Now, in Calypso - how would you measure #7,8?

I measured the Cylinder that is B, and used it to create a coordinate system as the Spatial and 2 directional origins. Then measured -D- as 4 2d lines around the surface of that cylinder in that coordinate system.

Reported the straightness of those lines.

And reported the Parallelism of Line 1 to Line 3, 2 to 4, 3 to 1 and 4 to 2, then reported the max.

My understanding of this is that it's very similar to the Parallelism of surface lines on Pg. 71 of the cookbook.