5 Replies Latest reply on May 1, 2015 4:40 PM by Jeff Holliday

    General tolerances note in drawing titleblock

    Atanas Kanov

      My question is in a way continuation of the discussion in this thread:




      I am starting a new discussion because I am not willing to further hijack the other thread.


      Our drawings are in mm. Currently we have this table:


      Many other companies do it the same way but we have encountered problems now and then because of it.


      We are considering replacing the table with a note like this:


      Unless otherwise specified tolerances are: H11-h11-JS11


      With a previous employer we were making all our parts in-house and it was understood that FOR ALL FREE DIMENSIONS:

      external dimensions will be machined at nominal or - and  all internal dimensions will be at nominal or +. (We did not even have it on the title block)


      It worked great for us- if I want a grove for a flat bar part for example I did not have to worry with tolerancing as they would oversize it and the flat bar will be undersized. (or shaft and bore)


      My question is: How many of you have similar approach and would you recommend different note?

        • Re: General tolerances note in drawing titleblock
          Jamil Snead

          I had included the example in the other post that is very similar to your current method. Another ball screw manufacturer I have seen uses a method very similar to your new proposed method.



          Since you have 3 tolerances, am I right in assuming H11 is for bores, h11 for shafts, and JS11 for linear dimensions? This may be understood but maybe it would be worth spelling it out like that.

            • Re: General tolerances note in drawing titleblock
              Atanas Kanov

              Thanks Jamil,

              I have also seen JS13.

              I am trying to move away from the symmetric tolerance.


              I like your suggestion. Then the note will become:


              EXTERNAL H11; INTERNAL h11; OTHER JS11


              My concern is that whoever manufactures the part will need to consult a table with standard tolerances. That is not much different than looking up drill sizes for tapped holes for example but I can see why someone might not like it,