1 Reply Latest reply on Aug 26, 2014 5:35 PM by Matthew Lorono

    Weld Symbol Dual Dimension

    Shane Villafuerte

      OK, I am about to begin an argument with my company (Older employees and
      shop personel) about the fact that they want us to have Dual dimensions in our
      weld symbols. They have already been doing this for years but our
      welds have never been real accurate callouts. And we already add a
      "crosshatch" to show where the weld goes (this is another issue I
      have but I am starting small on my arguments this time). Yes our drawings are
      all dual dimensioned so they assume they want the welds also dual dimensioned.
      I'm not sure what their arguments are going to be when we sit down but I can
      only imagine.


      I looked in the AWS A2.4:2012 standard and found:

      6.16 U.S. Customary and SI Units. The same system that is the standard for
      the drawings shall be used on welding symbols. Dual units shall not be used on
      welding symbols. If it is desired to show conversions from SI to U.S. Customary
      Units or vice versa, a table of conversions may be included on the drawing.


      So, the way I read this is that no matter how the drawing is dimensioned,
      the welds should never be dual dimenioned but only use the primary unit of
      measure on the drawing. And if a conversion is needed, to do that conversion by
      either adding a chart for the user to convert or refer to the AWS A1.1, Metric
      Practice Guide for the Welding Industry.


      Any and all input to help me in my quest would be greatly appreciated. I
      think I will need more agument points to bring up when I get this meeting as
      there are a lot of old school hard headed thinkers of :we have done it all
      these years so why change now"


      Also, the two major solid modeling packages we use, both do not use a dual
      dimensions weld, nor do they even allow the option to create one without making
      special symbols (which we have done before) and this is just fueling me more to
      drive this change of being correct from here on forward.



      Shane Villafuerte

        • Re: Weld Symbol Dual Dimension
          Matthew Lorono

          Never know what to expect when the first sentence of a thread posting is "...I am about to begin an argument with my company" 


          I wrote about Dual Dimensions a long time ago.  I didn't specifically address weld symbols, but rather the practice of dual dimensioning itself.  You might find this of interest:

          http://www.fcsuper.com/swblog/?p=72 .


          There's nothing there that is going to win you an arguments against dual dimensioning outright (other than the fact that dual dimensions were removed from the ASME standard in 1982), but some of it may help and be of interest.