Another GD&T Question

  • Filter
  • Time
  • Show
Clear All
new posts

  • Another GD&T Question

    Good afternoon.

    Is it true that positions that are called out on a detail drawing do not pertain to final drawing? For instance, we will be running a part that calls for true position callouts on the detail level. On the final part, bosses get welded into the holes. Does the true position callout no longer apply on the final weldment since it is not called out on the final weldment print? So when the part gets welded and the bosses flex one way or the other, we will still have a good part? Is this a quality standard or simply based on customer preference?

    Thank you.

  • #2
    Not a quality standard. Not really a customer preference. More like a design/functional requirement.

    tl:dr The final drawing should define all the relevant characteristics the final part must meet.

    Last edited by Wes Cisco; 11-15-2019, 01:50 PM. Reason: some thief stole an 'e' from my post, so I replaced from stock
    sigpic"Hated by Many, Loved by Few" _ A.B. - Stone brewery


    • #3
      Y14.5 Rev 2009, Dimensioning and tolerance reference section 1.4 Fundamental Rules
      (o) Dimensions and tolerances apply only at the drawing level where they are specified. a dimension specified on one level of drawing (e.g., detail drawing) is not mandatory for that feature at any other level (e.g., an assembly drawing)

      I think this is what you are looking for, this is 2009 not sure if that was changed on latest and greatest
      that being said your customer may require proof of conformance at the component record, an inspection report


      • #4
        Engineers' do not always think to the next steps of the manufacturing process. They could just assume that the true position will be controlled by the child part. Most engineers' think of there part in a 3D state of existence rather than in a literal state. I have came across this many times with my engineers'.


        Related Topics


        • Guest's Avatar
          True position Formula
          by Guest
          Can anyone tell me what the formula is for True Position? For whatever reason this engineer thinks that the true position should have a bilateral tolerance....
          06-12-2008, 06:22 PM
        • GEO3D
          True Position ISO 2768-m
          by GEO3D
          I am currently programming a job from drawing with a hole with no true position specified, it has boxed dimensions which would imply a true position....
          02-23-2016, 12:13 PM
        • Allen Long
          true position
          by Allen Long
          I am running 4.2 mr1
          I am running a fairly large part (43 inches) that has holes drilled on the outside .260 dia. , 4 places not equally spaced...
          01-15-2008, 01:17 PM
        • ag162
          True Position Question
          by ag162
          Good Morning Everyone,
          I have a question about a TP callout. The part that is being measured has a cylectrical area. The control frame has tp...
          06-18-2006, 10:23 PM
        • oriental_sun
          True Position/Engineering
          by oriental_sun
          Good morning all, i will try to make this short and to the point. I have a engineer that it telling me that when he puts true position on the print he...
          02-05-2011, 04:42 AM