Rectangular Ordinate Dimensioned Drawing 6

[sspatriots]

Hi,

The company I work for does a lot of machining for other companies as well as our own. I came across a drawing last week where there was a front view, right side view and to the right of that the view from the backside. In the front view there was a bore that was dimensioned as 0, 0. The bore was about 2/3 the way down from the top in that view, that is, it was not in the middle of the part vertically in that view. Then in the adjacent view looking in from the right side there were 4 tapped holes (one at each corner). The horizontal (x direction) 0 baseline in this view was shifted up to be at the center of the pattern for the 4 holes. I had always learned that the horizontal 0 baseline should carry across to all adjacent views and not move up or down if they are indeed standard orthographically projected views. Am I off base here in my thinking? If not, can someone point me to a reference that either explains my thinking or refutes it?

Also, that third adjacent view to the right of the right side view actually had the 0 baseline moved back up where it aligned with the front view.


Thanks,

Steve

 

[CheckerHater]

drawoh,

Essentially, no GD&T means no answer to your question, exactly because drawing can have different interpretations.

WITH GD&T you take your measurements from something as close as possible to perfect datum planes, A.K.A. “datum simulators” – you know the drill.

Nice picture included

 

[drawoh]

CheckerHater,

You are highlighting a problem I actually did not bring up. Just where the heck is that edge anyway? This is defined by ASME in their section on datums.

--
JHG

 

[CheckerHater]

Maybe I didn't make myself clear:

The fact that there is no answer to your question is the reason they invented GD&T in the first place.