Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations The Obturator on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

"Gage" for part

Status
Not open for further replies.

UchidaDS

Mechanical
Sep 28, 2011
116
I have a part and I would like to create a "gage" (as a quick reference).
Gage will be made out of SST. When consider this "gage" (I don't know what should I call it in proper way), I am thinking from the Virtual Condition Boundary.
The part has a default tolerance of +/-.010".
Gage default tolerance is +.001/-.000" unless specified.

Note that no matter the part is at free state or retrain state, it should fall in the size and feature tolerance.
The "gage" as shown is in Blue color. My uncertain is the dimension and tolerance.
If the part able to fit the part, it is consider "Go". The .090" step is to check the part's flange not sticking out.
Did I miss anything? Thanks for the help!
 
Replies continue below

Recommended for you

In order to build the gage properly you need to add some geometrical relationships to your part drawing:

- Perpendicularity tolerance of bottom surface to datum axis A is missing (assuming that the diameter A is primary datum feature and the bottom surface of the flange is secondary datum feature).

- Locational tolerance of dia. 13.375 to datum axis A is missing too. Without it you are not able to calculate virtual condition of the outer diameter of the flange properly. Additionally, this tolerance (most likely position, if you work to ASME Y14.5) will have to be defined at MMC if you want to use a gage having features fixed in size. For the very same reason datum reference to A in this positional callout must be followed by (M) modifier.

- In general, it would be at least reasonable to consider bottom face as a primary datum feature and dia. 11.500 as a secondary, of course if function of the part allows it.
 
Hi pmarc,
I had clarified the part's GDT. I made a mistake at the previous attachment (part).
Please see attached. Not sure do I need the circularity call-out (for the gage) or it will be taking care by the gage size tolerance?
 
 http://files.engineering.com/getfile.aspx?folder=d9fea0ee-51d4-4e43-8ac3-ea87968b87a6&file=Part_and_Gage.JPG
When I was mentioning about applying MMC (MMB) modifiers in positional feature control frame, I meant applying it on part drawing in the first place.
If you have access, you may want to take a look to ASME Y14.43 for more details about dimensioning and tolerancing principles for gages and fixtures.

As for circularity callout, there is no need for that, because circularity will be controlled by size tolerance of dia. 11.490 (.002 is less than .010).

But again, proper gage definition starts from proper part definition. Without it, I would say it is rather impossible to define really functional gage.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor