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Can we mention a datum twice in the same drawing? 2
- Thread starter VJ1988
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- #3
Vikas Jangre:
This is acceptable. You can repeat the datum symbol with the same letter as many times as you want, as long as it is applied to the same feature (in another view/section). Assuming a multi-sheet drawing, I recommend only adding it to sheets that depict a feature control frames (FCF) that have the letter in them (define a relationship with controlled feature and the datum feature).
Certified Sr. GD&T Professional
This is acceptable. You can repeat the datum symbol with the same letter as many times as you want, as long as it is applied to the same feature (in another view/section). Assuming a multi-sheet drawing, I recommend only adding it to sheets that depict a feature control frames (FCF) that have the letter in them (define a relationship with controlled feature and the datum feature).
Certified Sr. GD&T Professional
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- #6
Thanks Andrew and Mkcski.
One other question regarding to the pic posted is:
I got to know that datum mentioned on the left view is on the surface whereas datum mentioned on the right applies to axis.
If this is the case, then simultaneous representation of datum will not work. Am I right?
One other question regarding to the pic posted is:
I got to know that datum mentioned on the left view is on the surface whereas datum mentioned on the right applies to axis.
If this is the case, then simultaneous representation of datum will not work. Am I right?
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- #7
VJ1988
They both are interpreted the same and define the axis as the datum. This is a drafting issue. There are several ways to assign datum symbols to features of size. I suggest referring to Figure 3-4 and Figure 4-3 (d) in Y14.5-2009
Certified Sr. GD&T Professional
They both are interpreted the same and define the axis as the datum. This is a drafting issue. There are several ways to assign datum symbols to features of size. I suggest referring to Figure 3-4 and Figure 4-3 (d) in Y14.5-2009
Certified Sr. GD&T Professional
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- #8
Both instances of calling out the hole as datum feature "B" are in accordance with the standard and both mean/yield the same thing.
2009 4.3 (d) - "a cylindrical datum feature establishes a datum feature simulator that creates a datum axis (line) and constrains four degrees of freedom (two translations and two rotations)."
2009 4.3 (d) - "a cylindrical datum feature establishes a datum feature simulator that creates a datum axis (line) and constrains four degrees of freedom (two translations and two rotations)."
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