【转帖】ooling ball dim scheme

yang686526

tooling ball dim scheme
i am looking for guidance on methods to dimension a drawing that references a tooling ball for a series of holes drilled at a 30deg angle to the part.  does anything know the correct method or can you point me in the right direction by naming stardands that discuss this?  drawing examples would be nice too.
matt lorono
cad engineer/ecn analyst
silicon valley, ca
fcsuper, did you look at my post a couple of months ago on this topic?
kenat,
i may be wrong, but i believe that thread is discussing the opposite of what i need.  i've not done this before so maybe i'm missing something.  
my assumption is that i've already located the tooling ball and that the center of the tooling ball serves as the 0,0,0 for locating a series of holes which are being drilled at a 60deg angle to the part.
if this is an incorrect methodology, then i would be interested in correction.  (this method was presented by a machine shop.)
matt lorono
cad engineer/ecn analyst
silicon valley, ca
i have to say since your concerned with orientation on of your datums must establish the angular relationship with respect to.
xplicator,
???
powerhound, gdtp t-0419
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fcsuper you are correct the tooling ball does become the datum that you work from and yes it is totally different to the example kenat links to.
this is a standard way of working in fact i don’t know how else you could do it in 3+ or 5 axis machining or when changing the stylus on a cmm.
as for dimensioning standards i cannot help you there as the area i work in has long done away with 2d drawings and works solely to the model for machining and inspection, but i am sure others will be able to help.
powerhound,
yeah, been sick and couldn't sleep and after looking at my post i guess i was sleeping and the medicine was working, please note the time.  
my only comment is dimension per function only with unambiguous gd&t and let the machine shop figure out how to deliver it!
yeah, that's my understanding of the standards too.  however, in this case, i want to provide useful dimensions, and orthographic and aux views do not provide a method for this.
matt lorono
cad engineer/ecn analyst
silicon valley, ca