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Rookie needing some help with GD&T questions
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT=Calibri][SIZE=3][COLOR=#000000]Hoping I can get some help on some questions that I can’t quite find a clear answer for in either the ASME Y14.5 standard or already on this site (not the most experienced with GD&T yet).
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[/COLOR][/SIZE][B][SIZE=3][COLOR=#000000]Question 1)[/COLOR][/SIZE][/B][SIZE=3][COLOR=#000000], cylindricity- I have an application where we are welding up a bearing housing and machining afterwards. With the residual stresses in the bearing housing from the welding process, the bearing housings can slightly go out of round during the machining process. I already know that per the standard, the cylindricity tolerance must be less than the dimension tolerance. From previous application experience I know I need to maintain a tighter than normal control on the average size of the bearing bore. On the other hand, the bearing itself can handle a little more “out of roundness” than what my dimensional tolerance allows per the standard. The only thing I can find in the standard that could possibly allow my cylindricity tolerance to exceed the dimension tolerance is the “average diameter” as described in paragraph 5.5.3 of the 2009 standard. [/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][SIZE=3][COLOR=#000000]Is my “AVG/cylindricity” callout in the “housing” example legal? I don’t believe I would have to specify the free state condition in the feature control frame?? [/COLOR][/SIZE][/FONT]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT=Calibri][B][SIZE=3][COLOR=#000000]Question 2)[/COLOR][/SIZE][/B][SIZE=3][COLOR=#000000], Datum placement on a cylindrical surface-I think I already know the answer to this one…Is the placement of my datum feature A, B, & D legit?[/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][SIZE=3][COLOR=#000000]Per the Y14.5 2009 standard paragraph 3.3.2 section (a), I believe in my example it may be taken that these datum features are the surfaces themselves as opposed to the axis of the cylinders.[/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][SIZE=3][COLOR=#000000]However, in section (c) of 3.3.2 paragraph, it does state “placed on the outline of a cylindrical feature surface” in which I think I could argue that datums A, B, & D [/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][SIZE=3][COLOR=#000000]are on the outline on the cylindrical surface.[/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT=Calibri][SIZE=3][COLOR=#000000]I just ask this because on my actual drawings space is pretty tight and this is the cleanest way of specifying these datums.
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[/COLOR][/SIZE][B][SIZE=3][COLOR=#000000]Question 3)[/COLOR][/SIZE][/B][SIZE=3][COLOR=#000000], true positon of a keyway-Can someone confirm that I’ve properly used GD&T to locate the keyway position in the “shaft” example? I’m only concerned about the keyway being centered on the shaft on the datum C portion, axial location is not critical.[/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][SIZE=3][COLOR=#000000]I think it’s correct but I still have a little uncertainty….[/COLOR][/SIZE][/FONT]
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[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT=Calibri][B][FONT="Times New Roman"][SIZE=3][COLOR=#000000]Question 4)[/COLOR][/SIZE][/FONT][/B][FONT="Times New Roman"][SIZE=3][COLOR=#000000], locating of splines with GD&T-I also wanted to apply some GD&T to some internal splines in the shaft and relate it to the bearing seats (datum’s A & B) that this shaft is ultimately located by and spins on. This just to make sure that the mating splined output shaft of hydraulic motor will install into the piloted bearing housing with this splined shaft in. [/COLOR][/SIZE][SIZE=3][COLOR=#000000]I was just thinking of using true position for a coaxial relationship between the splines and the bearing seat axis and using the ANSI B92.1 callout for the machinist to refer to for the spline information.[/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][SIZE=3][COLOR=#000000]I can’t find any reference example on something like this, does this look legit?[/COLOR][/SIZE][/FONT][/FONT]
[FONT=Times New Roman][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][B][FONT="Times New Roman"][FONT=Calibri][SIZE=3][COLOR=#000000]Question 5)[/COLOR][/SIZE][/FONT][/FONT][/B][FONT="Times New Roman"][FONT=Calibri][SIZE=3][COLOR=#000000], true position of a hole drilled at an angle-I need to locate a hole drilled at an angle in a bore of a part as shown in the “housing” example. [/COLOR][/SIZE][SIZE=3][COLOR=#000000]Primary datum would be the axis of the bore and located off the face designated as datum E and clocked rotationally in respect to a cross drilled hole (datum F).[/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][SIZE=3][COLOR=#000000]The location of the hole where it intersects the large bore (1.00 basic dimension) is what’s the most critical.[/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][SIZE=3][COLOR=#000000]Did I correctly apply this positional tolerance?[/COLOR][/SIZE][SIZE=3][COLOR=#000000] [/COLOR][/SIZE][/FONT][FONT=Calibri][SIZE=3][COLOR=#000000]What leaves me in doubt that this is not correct is how does one apply the cylindrical tolerance boundary?
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I appreciate everyone’s input to the question/questions that he or she can help me out with. Thanks[/COLOR][/SIZE][/FONT][/FONT]
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