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Recent content by Burunduk

  1. Burunduk

    Datum callout question

    Or as shown in these examples... The first one is the same as using a Continuous Feature modifier for the 35+/-0.1 diameter.
  2. Burunduk

    Datum callout question

    Season, In the second case, there is no control over how off-coaxial the two ends can be. Here is an exaggerated illustration.
  3. Burunduk

    Datum callout question

    Tolerances for the fixture design should be about 1/10 of the tolerances being verified by the fixture.
  4. Burunduk

    How cylindicity works?

    greenimi, A cylindricity tolerance zone, whether per unit length or full length, is always 2 coaxial cylinders. Suppose a measured zone that is as long as the full length of the actual cylinder is best fitted over the actual 100 mm long cylinder and it should measure up to 0.4 mm. Then a 10 mm...
  5. Burunduk

    Datum callout question

    mfgenggear, I think there could be a go gage fixture as 3DDave described: two recesses of diameter 20.53 and a saddle of diameter 23.1, following the sections and bends of the tubing. I suppose it's not a cheap fixture, but if enough parts are to be manufactured, it should be worth the...
  6. Burunduk

    Datum callout question

    As 3DDave mentioned, most of those requirements can be verified with a functional go gage. That is because datum reference A(M)-B(M) is specified at MMB, and the positional tolerances referencing it apply at MMC.
  7. Burunduk

    Datum callout question

    If you delete the datum feature qualifying feature control frames, your datum features A and B will be left uncontrolled other than for size. If you keep those controls, the datum features A and B are controlled relative to a datum reference frame with all 6 degrees of freedom locked, so their...
  8. Burunduk

    How to convert linear dimensions to GD&T

    Why not establish a datum reference frame from datum features or datum targets and then apply simultaneous profile requirements to the left flat surface and to the right conical end of the hole. Also, a positional tolerance for the interrupted hole in the same DRF. Then do the tolerance stack to...
  9. Burunduk

    Diameter tolerance over a short length

    See "Limited Length or Area Indication" in ASME Y14.5.
  10. Burunduk

    Datum on hole pattern

    SEP REQT doesn't require two separate set ups, it just means that the unconstrained degrees of freedom in a single set up can be used to allow variation between the two features or patterns in a way that ignores their mutual basic location/orientation. One way to think of it is the act of moving...
  11. Burunduk

    Profile measurement question

    mfgenggear, Sorry, I'm not sure I follow. Possibly I wasn't clear enough with the question too. I'd like the inspected profile to be based on both dimensions 35 basic and 105° basic, not just 105° basic which is leveled to horizontal condition by the sine bar set at 15° (or that would only be an...
  12. Burunduk

    Profile measurement question

    mfgenggear, One more question if possible: How would you make sure that the location of datum axis A is repeatable for all measured parts, and independent on the variation allowed in the diameter of datum feature A (Dia. 20+/-0.05)? Note that in my illustration the axis location is approximately...
  13. Burunduk

    Profile measurement question

    "All I wanted to accomplish with my question was to hear that an optimization would be needed..." And it's good that you did 🙂 It's a good and important point.
  14. Burunduk

    Profile measurement question

    pmarc, that's why I said "unless I'm missing something critical" :) But speaking seriously, I think that the unconstrained degree of freedom makes it OK to optimize the rotation of the part around the datum axis for having the "best-fit" to a horizontal condition. Although on second thought, it...

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