7 Replies Latest reply on Mar 10, 2015 12:47 AM by Dinesh Sharma

    Metric Tolerance Question

    Frank Phelps

      Capture.JPGCan someone explain how to interpret these metric tolernaces.  I know the diameter symbol and number, but how should I read the

        • Re: Metric Tolerance Question
          Zac Evans

          It should be read as a just like a +/-, it's a tolerance as in 2mm (-0.007 to -0.011)

          Could also be read as 1.993-1.989mm.

          • Re: Metric Tolerance Question
            Dan Armstrong

            Hey Frank,

                 I want to read these as bilateral tollerances, but the drawing does look a little strange to me as they are using "comas" instead of decimals and also what appears to be a double negative bilateral tolerance.  In any case, I would be inclined to interpret these dimensions as a diameter of 22mm +0 / -.08 , 7mm +0 / -.022 , and 2mm -.007 / -.011.

             

            So for example, the last one would translate to values of (1.993mm to 1.989mm.)

             

            This would be my best guess - to treat them like bilateral tolerances with the comma being a decimal.

             

            Good luck.

            • Re: Metric Tolerance Question
              John Burrill

              I would read them as bilateral tolerances as well.

              I think the comma is there instead of a decimal point because this is an ISO standard drawing prepared for europe (watch out for first -angle projection in the views)

              The doubly-negative bilaterial tolerance on the right-most dimension probably indicates an interference fit for the nominal condition.  That's a convention that varies from one manufacturer to another and usually for the convenience of listing the dimension as being a nominal stock size..  I personally, would just write it as 1,993 +0/-0,004 and let the machinist figure out the stock.