[Al...] Posted May 27 Share Posted May 27 Hello everybody, I'm measuring a piece wihere specific points are rappresented in the drawing with the respectives values in x, y and z and the respective tollerance also (4mm on each axis). I want to understand fi this formula is ok for measure the true position considering all the 3 axis. ( see attachments). Thanks in advance for your support and hope i have explained well the situation. Link to comment Share on other sites More sharing options...
[Ma...] Posted May 27 Share Posted May 27 Spherical tolerance would be more appropriate. More details of drawing would be helpfull ( at least TP callout ) Link to comment Share on other sites More sharing options...
[Al...] Posted May 28 Author Share Posted May 28 In the drawing the TP callout are the 4mm on each axis for the some specific points. I don't understand if is possible to evaluate the True Position as sperich for each point aplly the formula in the last post. For example for point T01.1 instead of calculating the the true position on each axis with a 4mm of tolerance, is it okey to measure the position with the spherical tolerance of 6.93mm? Link to comment Share on other sites More sharing options...
[No...] Posted May 28 Share Posted May 28 It depends on what the 4 mm tolerances are: dimensional tolerances (+/-) or true position tolerances? And what is the functionality of the part (is there a proper GD&T position callout anywhere else on the drawing)? If you add up the 4 mm in all 3 axes and square root like you did above, you get a cubic tolerance (what you calculate is the space diagonal of a cube). So this is not the same as a spherical tolerance, as a sphere of the same size (diameter 4) would cover much less volume than the cube and thus represent a more restrictive tolerance. Like I said, it depends on the function of the part resp. if there's a proper TP callout elsewhere. Link to comment Share on other sites More sharing options...
[Al...] Posted May 28 Author Share Posted May 28 attached you can find more details about the drawing, i'm considering the tolerance Ø4ABC for the cylinder only and i don't understand if i can apply the same tolerance for the evaluations of the specif points which are described in the table points with 4mm tolerance on each axis. Thanks and sorry if i'm not very clear explaining my doubt. Link to comment Share on other sites More sharing options...
[Ma...] Posted May 28 Share Posted May 28 There is normal TP for fine thread M12 ( btw nice typo - 6H would be class ) I see no need for those extra points, unless it was meant to be (P) - projected field Link to comment Share on other sites More sharing options...
[Al...] Posted May 28 Author Share Posted May 28 So it's not necesary to evaluate the TP of the point T01.1 and T01.2? Becouse in another drawing the table with xyz coordinates of the points ant their individual tolerances was the only indication for evaluating the position. Link to comment Share on other sites More sharing options...
[Ma...] Posted May 29 Share Posted May 29 If you are in doubts then ask engineer if it's possible. From what you posted there is no TP callout for those points, neither how you obtain them ( are they taken from thread or which element ). Link to comment Share on other sites More sharing options...
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