GD&T - Same Callout Applied to Many Dimensions
GD&T - Same Callout Applied to Many Dimensions
(OP)
I have a part that contains a number of tabs with slots around the perimeter of the part.

I would like to verify the position and width at the base of each slot. The challenge that I'm struggling to address is that the width at the base (red box) differs slightly for each slot. I'd like to avoid creating a drawing view for each individual tab slot and was wondering if there was something I could do that communicated that I would like the base width of each slot checked based on the model.
I've considered calling out a surface profile on both sidewalls and creating a single section view with a note below saying "TYPICAL 20 PLACES MARKED X" but that would check the entire length of the sidewall and I'm only interested in the width.
Would anyone have anything that I could do that I haven't considered?

I would like to verify the position and width at the base of each slot. The challenge that I'm struggling to address is that the width at the base (red box) differs slightly for each slot. I'd like to avoid creating a drawing view for each individual tab slot and was wondering if there was something I could do that communicated that I would like the base width of each slot checked based on the model.
I've considered calling out a surface profile on both sidewalls and creating a single section view with a note below saying "TYPICAL 20 PLACES MARKED X" but that would check the entire length of the sidewall and I'm only interested in the width.
Would anyone have anything that I could do that I haven't considered?
RE: GD&T - Same Callout Applied to Many Dimensions
RE: GD&T - Same Callout Applied to Many Dimensions
ctopher, CSWP
SolidWorks '19
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SolidWorks Legion
RE: GD&T - Same Callout Applied to Many Dimensions
If he applies a tolerance to the width, it becomes a feature of size.
The width should be something like 20×30.2±0.2. If the size tolerance is is critical and tight, the problem is solved. If the width is sloppy and not critical, then profile is the right way.
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JHG
RE: GD&T - Same Callout Applied to Many Dimensions
From the drawing, this dimension 30.2 is applied to virtual sharps. I don't think this is a feature of size.
Best regards,
Alex
RE: GD&T - Same Callout Applied to Many Dimensions
Proposal:
Use position for the hole. Control outer profile relative to each respective hole.
RE: GD&T - Same Callout Applied to Many Dimensions
Do you have a view in which you could label the tabs with numbers? If yes, you could change the 30.2 to a letter, say D, and then tabulate the widths to show them as D-1, D-2, D-3, etc. You could do the same thing with slot dimensions if they also vary.
RE: GD&T - Same Callout Applied to Many Dimensions
Option 1:
- use a surface profile between two points on both sidewalls of the tab feature
- would it be acceptable to use a view that shows all tabs and indicate each one with a note "TAB X". Then create a detail view of one tab and use this notation to express that the requirement applies to "ALL TABS LABELLED TAB X"?
Option 2:
- updated the callout to include the material thickness which makes it a FOS and appropriate to use the positional callout.
- negative of this approach is that I would need to dimension each tab feature
- the suggestion provided by pmarc (label the dimension with a letter and create a table) is great and would only require me to make one view
Anything that I've missed or that's wrong with either option?
RE: GD&T - Same Callout Applied to Many Dimensions
A better approach is the one TheTick proposed. Use position for the hole. Control outer profile relative to each respective hole.
Why do you want to control the minor fillets? There is no mating features that come into contact with the fillets.
Dimension 31.8 is not clearly defined. It is also not a feature of size.
Tab location is "largely" defined by the sides of tabs rather the fillets.
Best regards,
Alex
RE: GD&T - Same Callout Applied to Many Dimensions
The sidewalls of the tab at its base (including fillets) define the position (left/right) of the tab in the mating feature (see image below). The hole engages with a snap but that snap does not dictate left/right position of the tab.
I'm struggling in understanding how to implement this. I understand that I can define the position of the hole relative to the datums. To "control outer profile relative to each hole" means to me that I would need to create new datums using the hole and then use surface profile to control the tab walls back to the datums created by the hole?
This has been mentioned lots so I did some reading of ASME Y14.5 to try and improve my understanding.
In the image above, the wireframe view shows the two lines in orange that I've dimensioned. These lines are parallel ["two opposed parallel line elements"]. The tolerance isn't in the dimension directly but is covered by a default tolerance from my title block. If you exclude the lack of a direct tolerance can you help me understand why this would not be considered a regular feature of size?
RE: GD&T - Same Callout Applied to Many Dimensions
why is the tab tapered?
combine option one and two and use gage points mid point of the tabs to measure the width. also the angle of each side will have to be specified. then use a true position or profile of surface. way easier then measuring a theoretical internal sharp corners.
to measure gage points a cmm will be required. but the tolerance should be liberal. eg you could make d view and e view
RE: GD&T - Same Callout Applied to Many Dimensions
RE: GD&T - Same Callout Applied to Many Dimensions
In your first image, there is an MMC modifier that follows the position tolerance value. It would actually make sense to apply it at the base of the tab so that the width includes the entire feature that is being engaged with the slot - including the two radii (according to the assembly depiction image you posted later down the thread). Then theoretically it is possible to inspect using a hard gage made as your worst case mating part. Easier and functionally more appropriate than having to engage the top tangency lines between the angled surfaces and the radii (the ones you've shown in orange).
RE: GD&T - Same Callout Applied to Many Dimensions
Chasing down root corners that intersect an organic surface is a fool's errand. Ditto for measuring off a tangency.
In cases where I can not measure a boss diameter or width at the end, I specify a basic distance from the end and measure at the section. CMMs can do this no problem. Also gage-friendly and repeatable.