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Thread: Old drawing gdt

  1. #1
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    Old drawing gdt

    I'm updating an old drawing with a note for controlling hole patterns, I want to change to modern GDT. heres what the dwg looks like
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  2. #2
    Administrator Kelly Bramble's Avatar
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    Pretty vague drawing... Are the holes all the way through? What are their function?
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  3. #3
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    this is a hopper, it has a hub with a feed screw coming in the left side and a spout on the other side, they want to make sure the two sides are within .060, I want to apply GDT instead of the old school note.

  4. #4
    Administrator Kelly Bramble's Avatar
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    So, your open end request has not been answered and though I know exactly what is required I would like for you to at least attempt to specify the datum structures as well as the related FCF to your design requirements....

    I am ASME Certified Senior GDTP, I train, consult GD&T and DFM/DFMA for a living but I'm not going to do your design for you...

    https://www.asme.org/wwwasmeorg/medi...fication_title

    http://www.engineersedge.com/GDT_Training.htm



    So let's see what you got..
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  5. #5
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    this is what I came up with, it just seams more complicated than the original note.HOPPER GDT R5.PDF

  6. #6
    Administrator Kelly Bramble's Avatar
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    Left Side View - Datums A, B are logical based on the information given.. Locating a BC is illogical in this case. You should locate the 4X orbiting holes back to datum's A and B then declare one or all hole features as datum "C".

    Right side view - Locating the Bolt Circle (BC) is again illogical.. Depending on the thickness (thin) of the Hopper part, I would simply locate all the hole features back to datum's A, B, and C to the tolerance required.

    If the hopper part is thick manufacturing becomes a challenge therefore I would Right Side View declare the outer (or inner) flat surface as datum D, maybe define a parallelism. Then locate the center hole back to Datum's D, B, and C, Then declare that hole datum "E". Then locate the four orbiting holes to datum D, E and C.


    seams more complicated
    Next time you want a high quality set of Michelin tires for your vehicle - simply tell the tire place "put tires on it" and see what you get...

    Proper Dimensioning and Tolerancing design is often the difference between a functioning, interchangable, manufacture-able part and something else..
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  7. #7
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    ok see if this is going to work
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  8. #8
    Administrator Kelly Bramble's Avatar
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    Total runout? not even close . You need training... At least read my book.

    See:

    Geometric Boundaries II, Interpretation and Application of ASME Y14.5-2009 GD&T
    http://www.engineersedge.com/geometr...ies-2-book.htm

    Basic of GD&T training per. ASME Y14.5-2009
    http://www.engineersedge.com/trainin...e-training.htm
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

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