Re: True Position

"Cliff Wild" <CliffWild@xxxxxxxxxx> wrote in
news:tKmdnfZwh_ng0FXenZ2dnUVZ_sWdnZ2d@xxxxxxxxxxx:


> The parts are called out as having holes in a pattern that are
> +/-.005
> from datum A (centerline of first pair of bolt holes(8 total) .50 from
> bottom edge of .750 plate(flat and parallel within .002) 6.50"X
> 10.00". Inside hole pattern in blocked and TP to AB and C within .002.
> The hole pattern is then repeated 3.000 two times. Screw holes exist
> that are TP with .014 but these are not even worth mentioning.
>

If I am understanding that correctly, the dimensioning is somewhat
ambiguous. ANY GD & T tolerance block should be attached to either a
dimension or feature via leader. Having a GD & T block out in space makes
no sense.
In my mind, is the Engineer attempting to have the TP tolerance apply to
the pattern itself, with a location tolerance of +/-0.005 from A, or is
it *really* effective to the datums? If it's to the datums as it
actually states, then the +/- 0.005 is a conflicting tolerance.

IMO, either the designer needs to leave off the reference to datum A, or
needs to remove the +/-0.005 tolerance.
Another question for the mindless...
Without a leader to a feature or tolerance, just exactly what does the
Engineer want toleranced to a TP of 0.002 to ABC?
Hell, this could be a block that he placed in the drawing to copy to
other relevant locations and forgot to delete. I really suggest you
contact him to see. As an ME myself, I have absolutely no issue with a
shop calling me direct to ask about a print. I would MUCH rather get the
communication of what I want vs. what you are going to make, if there are
ANY questions, down pat before you start cutting metal. Might save
yourself some headache and grief.
I have been known to actually go to local shops and go over complicated
prints with owners, or the machinist making the parts, one on one prior
to the start of work. I would rather have the RIGHT part, the first time.
I don't have the lead time for remakes due to communication problems,
whether it be with the way my drawing looks or verbally.


--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

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Relevant Pages

  • Re: True Position
    ... The hole pattern is then repeated 3.000 two times. ... is the Engineer attempting to have the TP tolerance apply ... If it's to the datums as ... > communication problems, whether it be with the way my drawing looks ...
    (alt.machines.cnc)
  • Re: Finally wrote-up my "How to Design Parts" section...
    ... Dale Dunn wrote: ... specific case of the tapped holes. ... tighten the tolerance to do it. ... I use fewer datums, because it's less work for them also. ...
    (comp.cad.solidworks)