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Circular runout on a cone with basic angle or with toleranced angle
- Thread starter Crvasu
- Start date
CheckerHater
Mechanical
@pmarc: it may be valid. But since runout doesn't control diameter, probably would work better if we kept profile as well.
We were discussing benefits using runout with basic angle, not runout with basic diameter (and location).
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
We were discussing benefits using runout with basic angle, not runout with basic diameter (and location).
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
pylfrm said:
pylfrm,
What would be the differences between your case (basic 24 diameter on fig. 8-18/ 2009 and added circular runout, along with already existing basic angle) and a profile (or maybe even a composite profile)?
What you are trying to control that profile (again or composite profile) would not help ?
Also, my main question still stays unanswered: What would be the difference or the benefit of having basic angle in fig. 9.2/ 2009 instead of ± angle?
Looks like some people agreed that basic angle is more beneficial than what is currently shown in the standard (± angle). What would be that benefit?
Also some disagree with this concept of having basic angle on circular runout.
pmarc
Mechanical
- Sep 2, 2008
- 3,248
Crvasu,
There is no need to ask for forgiveness. If this was up to me, I would use circular runout with basic angle, but not because the basic angle is required to make the runout tolerance valid. I would do it this way because I would want to apply profile of surface tolerance in addition to the runout callout. The profile of a surface tolerance would be required to control size (as 3DDave called it, the envelope) of the cone along with its form in axial direction (conicity, straightness of linear elements).
greenimi,
In ISO 1101:2017 (para. 7.1) they only say that the local width of the tolerance zones shall apply normal to the specified geometry unless otherwise specified, but they do not give a definition of "specified geometry". So it is the same problem as in Y14.5 where the term "true geometric shape" is not well-defined. I would personally treat it as "as-modeled" to avoid problems like the one mentioned by pylfrm with the 11.9-12.7 angle or with revolutes of complex geometry where no definable angle may be even existing.
CH,
What I meant by "it is a shame that the standard shows +/-angular dimension applied this way in the first place" is that this type of angular dimension has no clear, robust and unambiguous definition in the standard. This had nothing to do with runout tolerance. I do not want to hijack the thread but it is a similar problem to how they showed +/- linear dimensions in fig. 2-4. This should not happen, but fortunately it seems like they realized that, and in the new version of the standard this figure (2-4) will probably be modified to show basic dimensions and profiles. What is unfortunate is that the version of the draft I have still shows +/- angle in the figure that corresponds to fig. 9-2 in 2009 - the angle was just changed from 45 to 135.
There is no need to ask for forgiveness. If this was up to me, I would use circular runout with basic angle, but not because the basic angle is required to make the runout tolerance valid. I would do it this way because I would want to apply profile of surface tolerance in addition to the runout callout. The profile of a surface tolerance would be required to control size (as 3DDave called it, the envelope) of the cone along with its form in axial direction (conicity, straightness of linear elements).
greenimi,
In ISO 1101:2017 (para. 7.1) they only say that the local width of the tolerance zones shall apply normal to the specified geometry unless otherwise specified, but they do not give a definition of "specified geometry". So it is the same problem as in Y14.5 where the term "true geometric shape" is not well-defined. I would personally treat it as "as-modeled" to avoid problems like the one mentioned by pylfrm with the 11.9-12.7 angle or with revolutes of complex geometry where no definable angle may be even existing.
CH,
What I meant by "it is a shame that the standard shows +/-angular dimension applied this way in the first place" is that this type of angular dimension has no clear, robust and unambiguous definition in the standard. This had nothing to do with runout tolerance. I do not want to hijack the thread but it is a similar problem to how they showed +/- linear dimensions in fig. 2-4. This should not happen, but fortunately it seems like they realized that, and in the new version of the standard this figure (2-4) will probably be modified to show basic dimensions and profiles. What is unfortunate is that the version of the draft I have still shows +/- angle in the figure that corresponds to fig. 9-2 in 2009 - the angle was just changed from 45 to 135.
CheckerHater
Mechanical
@pmarc: Oh, I agree with your opinion on fig. 9-2.
"True" things are usually associated with basic dimensions, so using +/- IS a shame.
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
"True" things are usually associated with basic dimensions, so using +/- IS a shame.
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
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