geometric tolerences

[murugansubham]

hi,
i 've seen in one german drawing that represents GT.
They 've given in first frame flatness symbol, next frame 0,5 value and third frame 105,0 like this.
in generally we r using GT as first frame symbol, second frame tolerence value, 3rd frame it's reference plane.
that's why i want to know , what they mean to represent the above GT. is there any diff types to represent the GT? instead of ref plane , they 've given 105,0 value. what is the exact meaning of this value?
the total len and width of the flat surface is 250mm and 163 mm.

thank u,

regards,
Murugan. S
Design Engineer,
GlobalSoft Pvt Ltd,
INDIA

 

[murugansubham]

sorry. small correction , generally we r using flatness symbol in first frame and values in second frame only.
Thank u,

regards,
Murugan. S
Design Engineer,
GlobalSoft Pvt Ltd,
INDIA

 

[Mandrake22]

My assumption is that the feature is to be flat to within .5mm over any distance of 105mm.

 

[MadMango]

I would guess the same thing. The 1st value is the tolerance, while the 2nd value is the torlarnce zone.

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[murugansubham]

thank u friends for ur kind suggestions.


regards,
Murugan. S
Design Engineer,
GlobalSoft Pvt Ltd,
INDIA

 

[drawoh]

murugansubham,

I just took a look at my copy of ASME Y14.5M-1994, and I see no reference to anything other than a flatness symbol and a tolerance. A third number has no place in the ANSI/ASME GD&T system.

It is very likely that your German colleague is using the ISO GD&T standard, which may allow this. I do not know what the ISO standard is, and I have not seen any techanical articles on it. I think yuu are completely justified in asking him about this.

JHG

 

[murugansubham]

dear drawoh,
thanks for ur kind reply....

regards,
Murugan. S
Design Engineer,
GlobalSoft Pvt Ltd,
INDIA
murugan_subham@yahoo.com

 

[JNR]

Actually, the ASME and ISO systems were supposed to have been consolidated at the last rev. (I happen to know one of the guys on the committee.) For questions on SW use of GDT this is a good forum. But yours is not really a SW related issue so we might not be the best resource to help you. I think that for more informative answers to your question you might think about trying a different Eng Tips forum. Look down the list - there is bound to be a good forum for it.

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