12 Replies Latest reply on Aug 27, 2018 10:25 AM by James Riddell

    Still learning: Why are these tap callouts different? What makes them different?

    Kristina Smith

      Edit: Changed the thread title after a little thinking. I don't want to make the new callout look like the old callout if it's incorrect, I'd rather do it the right way. But I would like to understand why the new tap callout does not look like the old one.

       

      Hello,

      I'm not actually an engineer or trained drafter in any way, but I happen to know how to use Solidworks to a degree, and I do some gruntwork for my company. I've been tasked with creating a new drawing for a revised part, but the tap callouts being created by my copy of Solidworks don't look like the tap callouts on the old drawing. I'm hoping someone can explain why they don't look the same.

       

      Here is the M2x0.4 tap callout on the old drawing, which as I understand, was created in solidworks as well:

      IMG_20180825_112152901.jpg

       

      And here is the same hole with the tap callout in my Solidworks:

      2018-08-25.png

       

      I guess my question is, why does the original drawing just say "M2x0.4 TAP" while the callout generated by Solidworks adds tolerance and depth information? Is it necessary? If not, is there a way to match it to the style in the old drawing? These parts have been made successfully with the tap callout as-is in the old drawing, so at least for our application, it was apparently fine with just "M2x0.4 TAP".

       

      Does it have to do with the way the holes were made (Hole Wizard, Straight Tap with cosmetic threads)?

       

      (I cannot upload the part because it's a work thing.)

        • Re: Still learning: How do I get my tap callouts to look like this drawing?
          Deepak Gupta

          Kristina Smith wrote:

           

          I guess my question is, why does the original drawing just say "M2x0.4 TAP" while the callout generated by Solidworks adds tolerance and depth information? Is it necessary? If not, is there a way to match it to the style in the old drawing? These parts have been made successfully with the tap callout as-is in the old drawing, so at least for our application, it was apparently fine with just "M2x0.4 TAP".

          In general depth is specified for the blind holes/threads. And with out the depth there might be issue while creating the hole/threads. So please verify if that drawing is referring to a thru all hole/thread.

           

          In SOLIDWORKS call out is defined by what has been defined in the hole call out file. So your best option (since I believe that you can not modify the hole call out file) to match that drawing would be to remove the additional information from the call out by editing the call out properties.

           

           

           

          In addition check with your CAD administrator or your team leader to see if they want to fix it in the call out file itself so that next time you get the desired results.

          • Re: Still learning: Why are these tap callouts different? What makes them different?
            Rubén Rodolfo Balderrama

            Mornin' On metric Standard you don't need to type M2x0.4, normal sizes you don't need to write the pitch. Metric standard  is normal and omitted the pitch, you must type pitch for coarse and Fine only.

             

             

            A metric ISO screw thread is designated by the letter M followed by the value of the nominal diameter D (the ideal maximum thread diameter for external thread or the ideal minimum diameter for internal one) and the pitch P, both expressed in millimetres and separated by the multiplication sign, × (e.g., M8×1.25). If the pitch is the normally used "coarse" pitch listed in ISO 261 or ISO 262, it can be omitted (e.g., M8). Tolerance classes defined in ISO 965-1 can be appended to these designations, if required (e.g., M500– 6g in external threads).

             

             

            External threads are designated by lowercase letter, g or h. Internal threads are designated by upper case letters, G or H.

            • Re: Still learning: Why are these tap callouts different? What makes them different?
              Danny Edwards

              Kristina, I would also check where on the old drawing and click on the dimension and see if it was changed in the dialog box. If you see TAP typed in the dialog box that means the user inserted it into dimension and not a standard.

              • Re: Still learning: Why are these tap callouts different? What makes them different?
                Timothy Taby

                To a well trained machinist either print would be sufficient to create the hole.  However, the original print is slightly lacking in information by not providing a depth of the tapped treads (although most machinists will thread to the bottom of a blind hole, but if it's not stated then they don't have to and could still be correct) and also by not providing the thread tolerance grade. By using the format that the Solidowrks drawing does it provides all the information to create the hole with no questions, so any machinist should be able to create the hole properly.

                • Re: Still learning: Why are these tap callouts different? What makes them different?
                  James Riddell

                  The original designation reads:

                  "Drill two holes that are 1.60 mm in diameter and make them 5 mm deep.  Then thread that hole using a size M2x0.4 (metric) tap for the full depth (implied)."

                   

                  The SWX designation reads:

                  "Drill two holes that are 1.60 mm in diameter and make them 5 mm deep.  Then thread that hole with a size M2x0.4 using a Tolerance Class of 6H and make sure there is full thread for 4 mm deep."

                   

                  There is quite a bit implied in the original which is specified in the SWX version but as has been stated previously, you could just say make 2 holes that are M2 tapped 4 mm deep.  A 'real' machinist will understand that there is a tap drill size for the M2 and make the hole deep enough for full thread to 4 mm.  Depending on the application a bottoming tap may be required but this doesn't appear to be the case.