So in discussions at work, we decided that the absolute clearest way of communicating design intent is to start with views that define the coordinate frame by themselves with no part dimensions and only the linear dims to the datum targets/surfaces.
Having said that, we also decided that dwg...
Drawah
I agree with what you are saying,
" You need to provide a dimension to it. In ASME Y14.5M-1994, most of the examples show basic dimensions used to do this, which means that "...established tooling and gauging tolerances apply.". You may apply a tolerance to the datum target. You may...
Folks
The question is not what datum structure to use. That is functional and works fine. I am asking a more subtle question regarding dwg standards and how the datum structure is called out on the dwgs. I am asking if its ok to use an ordinate dimension scheme to define the datum structure, or...
JHG
Ah- you are correct, the axis of the bore IS the zero CL. BUT, I still need to clock the 0-0 CL. Imagine a cam with a hole in its middle. I have one point on one lobe of the cam as my tertiary datum. If I am making the inspection fixture, I need linear-style basics from the center of the...
Hi Drawoh,
Thanks for the note
I did not mention that yes, we have a primary datum "-A-" that as you suggest, is perp to the bore. So your scheme is in fact what we use. But in doing so, you still need to define basic dimensions between the datums (or datum targets, as the case may be) to set...
Folks,
I am new to this forum, but am hoping someone out there can help answer a debate I am having over GDT datum structures. I claim that the basic dimensions used to define a datum structure must not and cannot be ordinate-style dimensions (ie - the kind that have a 0-0 line predifined)...
