[Mi...] Posted August 18, 2022 Share Posted August 18, 2022 Of those who are familiar with this standered, what chart under 2768-2 would one use to tolerance roundness?? I'm thinking chart 4 but i'm not 100% on that... Linked is the pdf if needed Mike ISO-2768.pdf Link to comment https://qualityforum.zeiss.com/topic/9730-iso-2768/ Share on other sites More sharing options...
[Da...] Posted August 18, 2022 Share Posted August 18, 2022 You wouldn't. If the roundness requirement is not explicitly defined on the drawing, then the form is controlled only by the limits of size. Link to comment https://qualityforum.zeiss.com/topic/9730-iso-2768/#findComment-45792 Share on other sites More sharing options...
[To...] Posted August 18, 2022 Share Posted August 18, 2022 Does the drawing state the class in the legend? I know many drawings state UOS use Medium for the general tolerances.. Link to comment https://qualityforum.zeiss.com/topic/9730-iso-2768/#findComment-45794 Share on other sites More sharing options...
[To...] Posted August 18, 2022 Share Posted August 18, 2022 Please sign in to view this quote. Wouldn't this only apply if the drawing states ASME Y14.5? (Is there an equivalent rule for ISO?) What about a note in the drawing that says use a separate set of rules, i.e. OEM specific? Link to comment https://qualityforum.zeiss.com/topic/9730-iso-2768/#findComment-45796 Share on other sites More sharing options...
[Mi...] Posted August 18, 2022 Author Share Posted August 18, 2022 OK.. So if I have an ID on a part that has NO roundness/circularity call out how would u tolerance that if you checked it? Print is drawn with the 2768mk standered referenced in the title block so I was assuming you had to use that to tolerance the circularity /roundness since its not actually drawn on the part. And which table does the circularity/roundness fall under?? Am I off base on this one... Link to comment https://qualityforum.zeiss.com/topic/9730-iso-2768/#findComment-45798 Share on other sites More sharing options...
[To...] Posted August 18, 2022 Share Posted August 18, 2022 If you're using Rule 1, perfect form at MMC. Form can increase on a 1 to 1 ratio as you depart from MMC. Link to comment https://qualityforum.zeiss.com/topic/9730-iso-2768/#findComment-45800 Share on other sites More sharing options...
[Ri...] Posted August 22, 2022 Share Posted August 22, 2022 Please sign in to view this quote. Yes this applies to ASME Y14.5, I believe as far back as 1982. Link to comment https://qualityforum.zeiss.com/topic/9730-iso-2768/#findComment-45802 Share on other sites More sharing options...
[Ün...] Posted August 23, 2022 Share Posted August 23, 2022 We had a lot of problems with the engineer team on this issue. We use half of the diameter tolerance for the circularity / roundness that is not given in the technical drawing. In the programs from the customers, I saw those who entered half the diameter tolerance or the value equal to the diameter tolerance. I guess everyone enters a value based on where the part is used. Link to comment https://qualityforum.zeiss.com/topic/9730-iso-2768/#findComment-45804 Share on other sites More sharing options...
[Ri...] Posted August 23, 2022 Share Posted August 23, 2022 While it appears there isn't a direct tolerance for Roundness - there is a general tolerance for Runout - which would be controlling both the roundness and position. I find it strange that there is a general tolerance for Straightness and Flatness. I've never understood ISO either way. Why would you need to explicitly state that size and form are not independent? It seems to me that a lot of ISO drawings are all about measuring a part "within spec", and hoping it functions. Link to comment https://qualityforum.zeiss.com/topic/9730-iso-2768/#findComment-45806 Share on other sites More sharing options...
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