GD&T re Hex shaft with 2 different Hex sizes
GD&T re Hex shaft with 2 different Hex sizes
(OP)
I am an ME, now disabled, working from home (95% for my 35 yr. career was spent in mfg. mgmt. – so I am very rusty) and am designing a drilling center for drilling a hole in ea. side of a Hex coupling nut (simultaneously). Need a bit setup gauge for bit changes in the drill heads utilizing the pic & place system. It has 2 sizes of Hex on the same short shaft. Need to Tolerance this for making the sides of the 2 Hex sizes within certain degrees of each other around the center axis. Do not know quite what nomenclature to use in the FCF.
Any suggestions would be appreciated!
Thanks,
Larry
Any suggestions would be appreciated!
Thanks,
Larry





RE: GD&T re Hex shaft with 2 different Hex sizes
2) "Bit Point -0.25" should be "DRILL CENTER .25" (There are no negative distances. Distances are absolute values. Coordinates can be negative, not linear values.)
3) What's the purpose of the larger hex size?
4) Look into "Parallelism" or perhaps "Angularity". I believe "Parallelism" would be more appropriate.
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NX8.0, Solidworks 2014, AutoCAD, Enovia V5
RE: GD&T re Hex shaft with 2 different Hex sizes
Thanks for you input, it has been very helpful and has caused me to rethink the design in order to simplify the gauge.
Larry
RE: GD&T re Hex shaft with 2 different Hex sizes
RE: GD&T re Hex shaft with 2 different Hex sizes
GD&T datums are always based on a functional gauge. Just because there isn't a predefined symbol for your situation does not mean you should limit yourself to the symbols. Besides if there is an exotic callout and the reader doesn't understand it, it does you no good.
In this case, I would consider declaring a datum axis as being the centerline formed by a "three jaw" hold on one hex (preferably the narrower, longer one), and then limit the distance from that centerline to the faces of the other hex. That will control both overall size of the second hex as well as the centering of it.
Then it's a matter of applying size dims and parallelism tolerances to the faces of the "datum" hex.