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  1. tgwow

    Tolerance Zone of R is ambiguous

    Xplicator, On the contrary, this has been extremely valuable. My major issue is this: If it's difficult to show the tolerance zone of R+/- then wouldn't it be difficult or even next to impossible to verify that your parts are good? Thus, using R without GD&T is no good in practice. GD&T...
  2. tgwow

    Tolerance Zone of R is ambiguous

    My point is this. If R+/- is so deficient then it has no place in any drawing except for breaking edges. I see R+/- used all the over the place without GD&T.
  3. tgwow

    Tolerance Zone of R is ambiguous

    Yes, I'm definitely not an expert on the standard. That's why I'm here. I understand that I can define my drawings with no ambiguity with GD&T. My question is "In general can R be used meaningfully without GD&T?" So help me out. Pick any one of the three shapes, add your +/- dim scheme...
  4. tgwow

    Tolerance Zone of R is ambiguous

    powerhound, I'm completely at ease with Figs 6-12 and 6-13. The tol zones are well defined. However, I'm not completely sure of how to even draw the tol zones for the simple shapes (for any or some chosen dim scheme with R+/-) I drew. I'm getting the sense that R+/- is not be well defined...
  5. tgwow

    Tolerance Zone of R is ambiguous

    Yeah, they're different animals but I'm concern about the "kingdom of animals". I'm concern with a generalization of the whole "kingdom of animals". It's like saying "animals should have legs." The End. So where do the legs go? Enough of that:) So the Section 2.15 Radius, where it...
  6. tgwow

    Tolerance Zone of R is ambiguous

    powerhound, Thank you for your response. And I do subscribe to what the standard says. Let's put things in some context here. (1) Section 1.8 talks about how to dimension diameters and radius and what the graphics should look like. (2) Section 1.8.5 says to draw rounded corners using an R...
  7. tgwow

    Tolerance Zone of R is ambiguous

    Kenat, Remember that CR used to be called Tangent Radius from 1982 so yeah, why? I think the definitions of the tolerance zones for R, CR and the figures are not well defined enough to say that the tangent sides are included or not. There should be no ambiguity even when pushed to the limit...
  8. tgwow

    Tolerance Zone of R is ambiguous

    If you examine figure 2-18 carefully, there is no flat (tangent sides) where there should be. It's quite evident that you can see the jagged edges of curvature. Try modeling those dimensions and you can see the flats are quite clearly defined. The flats are large enough to see. Thus, even...
  9. tgwow

    Tolerance Zone of R is ambiguous

    Kenat, The problem with your sketch is that the definition doesn't say use MIN R, tangent lines, and MAX. It just says to use MIN R and MAX R. Additionally, the MAX R arc doesn't have to be tangent to the sides so you can move the MAX R arc towards the corner and tilt it. Even if we make the...
  10. tgwow

    Tolerance Zone of R is ambiguous

    powerhound, Thank you for your responses. Extending the principle based on 1.8.5 and 1.8.6 does seem appropriate and reasonable as an implication. However, I still think my original premise is still true due to the deficient definition in the standard. The tolerance zone for R is...
  11. tgwow

    Tolerance Zone of R is ambiguous

    Thanks dgallup, that's a nice tip! I tried it and it worked. Will need to train everyone so they know what's going on though.
  12. tgwow

    Tolerance Zone of R is ambiguous

    Kenat, We're kind of going on a tangent but for parts which are molded I've seen requests from suppliers who would want the CAD model modeled at nominal which would mean in order to "show" the dimension from the model on the drawing for "R4 MAX" and keep it parametric, "R2 +/-2" would be...
  13. tgwow

    Tolerance Zone of R is ambiguous

    powerhound, Section 1.8.5 and 1.8.6 requires that the actual part geometry be tangent to the sides but says nothing about the tolerance zone. Therefore, why would you draw the min and max arcs tangent for R? Additionally, the definition of the R tolerance zone does not state inclusion of...
  14. tgwow

    Tolerance Zone of R is ambiguous

    ctopher, How could the tol zones be the same when CR requires tangency and R does not? The tol zones in the figures in ASME for R and CR appear the same but are they really the same? Try drawing it for the example of R2.4 +/- .3 from ASME. Because the arcs aren't require to be tangent, the...
  15. tgwow

    Tolerance Zone of R is ambiguous

    ASME Y14.5m, 1994 Section 2.15.1 Radius Tolerance states: "A radius symbol R creates a zone defined by two arcs (the minimum and maximum radii). The part surface must lie within this zone...." Section 2.15.2 Controlled Radius Tolerance states: "A controlled radius symbol CR creates a...
  16. tgwow

    Hole defined as datum feature

    One thing I might add is that if Datum B is callout at MMC/LMC then the second hole is positioned relative to the virtual condition of Datum B and not the feature defined by B. Therefore, the second hole would only shift if the second hole's geo tol calls out Datum B at RFS.
  17. tgwow

    Datum shift

    Likewise, unless I'm misunderstood also, on the contrary, I would say it is legal. Datum shift comes from MMC/LMC callouts on your Datums and it's legal when your datum(s) are Features of Size (FOS). Additionally, you can choose to control your feature with RFS/MMC/LMC where MMC/LMC, for FOS...
  18. tgwow

    Bending a solid part

    If your louver is a simple part, you can design the flexibility into the part by using a 3 point spline. Lock down the endpoints of the spline and dim the center point of the spline. This dim will give you the flexing action. If your louver is a more complex part, check out spinal bend. It...

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