[AT] Transmission oil, 90-wt? Now: drawings

[John Hall]

Occasionaly we see someone changing a dimension but not redoing the drawing. 
Definetly a no-no as you said. We always keep a paper copy and the 
electronic drawing if one was given. Depending on the customer we keep a 
master paper copy that is not allowed to be written on or even removed from 
the office. Any problems/ deviations are marked up on the print on the 
floor. Generally these parts have the drawings fixed by the customer before 
the parts are run again. If it is something we are designing, the marked up 
print is sent back to engineering. CNC progarms are only accesible by 2 
computers to keep curious folks from accidentally changing something. I'm 
still old fashioned in that we still print out the programs. Helps in 
setup---assuming the setup man can read G-code!!!!

If you think of how confusing it can be to get parts made right 
nowadays---imagine what it was like back when our old-iron was built!! 
Instead of taking 5 minutes to make a revision and verifying that it would 
work, an engineer could spend all day and have to clear through a half dozen 
other folks!!!

John

----- Original Message ----- 
From: "Larry D. Goss" <rlgoss at evansville.net>
To: "'Antique tractor email discussion group'" 
<at at lists.antique-tractor.com>
Sent: Tuesday, September 05, 2006 10:57 PM
Subject: RE: [AT] Transmission oil, 90-wt? Now: drawings


> The difficulty with dimensioned drawings is that there are companies
> that routinely treat the dimensioned drawing as the official document
> for the design (which it used to be, historically) rather than letting
> the electronic database have precedence.  I even caught the author of a
> major drawing textbook trying to inject information about how to make
> hand corrections to the plotted output from a CAD package.  That is
> plain and simply an ethical and legal No-No.  The database and the
> drawings have to agree with each other.  The plotted or printed output
> (drawing) from a CAD package is nothing more than refrigerator art.  All
> of us know what refrigerator art is -- Johnny or Susie brings a paper
> home from school, shows it to their parents, and it gets posted on the
> refrigerator until the next piece of paper is brought home.  But you
> don't correct it, preserve it, or otherwise treat it as anything except
> a "check print".  In the case of an engineering drawing, you most
> certainly don't take dimensions off of it or scale the drawing directly
> to determine any measurements.  If a company doesn't have the capability
> of going directly from the 3D model information to a tool path without
> referring to the drawing, they're in trouble.  They're likely to find
> fewer and fewer contracts coming their way.
>
>> Larry
>