Can I use a flag note to define a datum target?
Can I use a flag note to define a datum target?
(OP)
Hi.
I'm trying to create a drawing that is basically a work instruction for measuring a feature. The datum target is the center of a counterbore feature. I'm not allowed to put dimensions on the print because it is a work instruction that applies to multiple parts....
How can i identify the datum target feature if I can't use a dimension? My thought was to use a flagnote. Is this totally innapropriate?
Its a work instruction, not a manufacturing drawing, so I dont think violating ASME is an issue, but my own curiosity leads me to wonder how you would do this according to standards...
I'm trying to create a drawing that is basically a work instruction for measuring a feature. The datum target is the center of a counterbore feature. I'm not allowed to put dimensions on the print because it is a work instruction that applies to multiple parts....
How can i identify the datum target feature if I can't use a dimension? My thought was to use a flagnote. Is this totally innapropriate?
Its a work instruction, not a manufacturing drawing, so I dont think violating ASME is an issue, but my own curiosity leads me to wonder how you would do this according to standards...





RE: Can I use a flag note to define a datum target?
A datum target is a special type of datum feature where only a selected portion of a feature (surface) is used to derive the theoretical datum. If this were desired, and dimensioning not allowed, then I would add a note under the datum target balloon symbol saying "shaded area only" and then cross-hatch the desired region.
But either way, a flag note can be used if nothing else suffices.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: Can I use a flag note to define a datum target?
I took a look at the ASME book and I understand datum theory better now. (Full disclosure, I'm a designer not an engineer...but the job I'm in now has me taking on more of a role with the engineers and working with prints).
I ended up creating datum axis a on the overall length of part, b on the width of part, and c on the rim of the c'bore to create datum references.
Thank you.
RE: Can I use a flag note to define a datum target?
Is there a chance we could see even a rough sketch of how you did it?
RE: Can I use a flag note to define a datum target?
What I did was dimension the overall length as 'L' and added my datum to that dimension, indicating the datum axis is to run through the center of the part. (I added a note to refer to customer drawing for dimension 'L') I did the same for the width.
I created a detail view from a cross section through the c'bore and added a datum callout to the flat of that feature.
Then I just wrote instructions like "2x 'A' from center of gage ball to Datum A" or "4x 'C' from center of gage ball to Datum B"
And lastly I have a table for the dimensions 'A', 'B', 'C', etc which are all basic dimensions.
I know without a visual its hard to say if that works or not, but I think it would meet standards.... The customer drawing has dimensions that say "'X' to datum A" and some that are to datum targets (which is why I used a datum target in the first attempt)
RE: Can I use a flag note to define a datum target?
If you need to show dims and datums etc, attach the drawing to the work instruction. Or, reference the dwg in a note.
Chris
SolidWorks 10 SP5.0
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