Measuring Feature Location from a Theoretical Centerline

P

PaulJSmith

#1
Good Morning, Covers!

I've been going 'round and 'round with design engineers for years over this, and I find myself faced with it yet again. I have a formed sheet metal part (a mounting bracket). It is supposed to be symmetrical ("-ish", according to the engineer). The drawing shows all dimensions measured from a theoretical centerline. One end has a threaded pem insert centered on the centerline. The other end has a 90? bend with 14 features, all measured from said centerline, and none centered.

Any suggestions on how to get an accurate measurement of the locations of these features, one that doesn't involve tolerance stackups?
 
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Michael_M

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#4
Is the drawing subject to more than one interpretation? When I was taking drafting classes, the instructor (a guy who worked in the field and taught at night) was animate about "a drawing is subject to only ONE interpretation".

Can you attempt to use this as part of your argument?
 
P

PaulJSmith

#5
Is the drawing subject to more than one interpretation?
No, it's pretty clear.

I can - and have, entirely too many times in the past - just double each feature's location dimension and measure their distance from each other, or measure them relative to another known feature. The first, though, won't tell me if they are shifted off center, and the second runs into stackup issues.

I guess I'm just ranting about never getting good, solid, REAL points from which to measure. Makes it difficult to accept a part from a vendor with any certainty.

Just crabby today, perhaps. :mad:
 
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