7 Replies Latest reply on Sep 29, 2014 7:06 AM by Matthew Lorono

    Do notes have priority over title block information.

    Ron Reiners

      I have a number of drawings that have a note that states the tolerance is +/-.010, +/-.025, etc.. The standard title block on all the drawings have a hard written tolerance block with +/-.005. This is not a variable field, just +/-.005 on all formats.

       

      I now have one vendor that is questioning it. I don't want to manually  update the format on individual drawings out of fear that someday down the road someone will change the format to a different size or when there is a new company logo and then the tolerance would change back to the standard title block tolerance. I suppose I could change the title block tolerance to a variable but then there is a chance that other may forget to set the variable on new drawings.

       

      I have looked thru the ASME specs but haven't found anything that states that notes take precedence over the title block. Does anyone know if there is anything called out stating what has precedence? How is everyone else handling this situation?

       

      Thanks,

       

      Ron

        • Re: Do notes have priority over title block information.
          Glenn Schroeder

          I don't know about following any specs, but would it work to modify your title block in your sheet formats to say that tolerance is +/-.005 "unless otherwise stated"?  If you do, be sure to Reload the sheet format in your drawing templates and save so they'll be updated.

            • Re: Do notes have priority over title block information.
              Ron Reiners

              Glenn,

               

              Thanks for the response.

               

              I do have a couple of options going forward, including adjustments to the standard drawing template.. However I need to investigate and determine if this particular case violates any drawing standards or not.

               

              Ron

                • Re: Do notes have priority over title block information.
                  Daniel Andersson

                  I agree with Glenn Schroeder. Update the title block.

                  Without seen you title block it sounds like it is not really stating what is needed. I would say that a tolerance just in the block without "Unless otherwise stated" or similar text is just a tolerance that is impossible to relate to.

                   

                  It will be quite contradictory to have two statements like this, one in title block and one as a text on the drawing... you can only have one.

                   

                  I would set up different text blocks to insert if different general tolerances is needed from item to item and remove the tolerance information from the title block. Me personally likes to have all item requirements such as tolerances, surface treatment etc in text blocks instead of adding that into the title block. I'm one of those who thinks the title block should contain document information and very very basic item information. Such as P/N, Description, Drawn date, Drawn by, Approved date, Approver, Revision etc.

              • Re: Do notes have priority over title block information.
                Kelvin Lamport

                Almost every drawing I've seen has had a title block area stating the tolerance to be applied to the number of decimal places, and a note stating "Unless Specified otherwise".

                 

                Special tolerances should be applied to individual dimensions.

                  • Re: Do notes have priority over title block information.
                    Ron Reiners

                    Thank you both for your responses.

                     

                     

                    Let me explain a little more. These are legacy drawings, that I have inherited, that have these general notes added. Although they are in CAD format now, all of them are 10-15 years old and their origins may have started in the days of drafting tables with velum and pencil.

                     

                    The drawings that are in question have a title block tolerance section that states "unless otherwise specified", and 3 place decimal = +/-.005.This is not a blank field that needs to be filled in or a variable in which you can go into the properties of the drawing and set the value.

                     

                    The notes on these drawings state 3 place decimal = "something larger than +/-.005". Also some, but not all, of them also state "unless otherwise specified" in this note.

                     

                    I an not questioning whether this is a good practice or not. I understand that it is a poor practice at best. What I really need to know is if there is conflicting information, or the appearance of conflicting information, between the title block and the notes or the detail views, is there any specification (ANSE or other) that states one has the priority or supersedes the other.

                     

                    The reason for this inquire is two fold. 1. I have plenty of work to keep me going 50 hours a week without having to research through 1000's of files to find these specific drawings and then update them. 2. I need to thoughly explore all my options before I present my decision to allocate time and effort to make these changes which may interrupt other projects and timelines.

                     

                    My thoughts that there might be a specification about this subject revolves around the way manual drafting was done before CAD when formats were printed in ink by printing companies. In that time it would have been much easier to add notes instead of erasing parts of formats with electric erasers.

                     

                    Ron

                      • Re: Do notes have priority over title block information.
                        Jamil Snead

                        If the title block tolerance states "unless otherwise specified" as you say then there is no conflict of information. The note with different tolerances means that the tolerance is otherwise specified, so the title block note is nullified and superseded by the drawing note. However, if you have a drawing note that says tolerance is +/- .010 or something and that note doesn't say "unless otherwise specified", then you risk having a conflict if you individually tolerance a specific dimension. That is unless the dimension has a number of decimals that is not covered by the note.

                         

                        If the drawing note and the title block both say "unless otherwise specified" then there is ambiguity because it is not clear which supersedes which. In that case I would draw lines (on the main sheet) to cross out the title block text. Even if the title block is updated as long as the tolerance text is in the same place the lines should remain crossing it out.

                    • Re: Do notes have priority over title block information.
                      Matthew Lorono

                      The ASME standards state that you cannot have more than one intepretation for each dimension.  This means if you don't state the tolerance within the dimension, the global tolerance applies.  If you have two global tolerances (particularly when they are different for the same dimensions), then your drawings are not in compliance with the standards.   You will either need to make it clear when a particular global tolerance applies, or only list one global tolerance on the drawing.