WHAT'S THE BEST GD&T CONTROL TO USE?

[learningchecker]

I have a spring with one leg horizontal then .072 BR angling down 15 degrees. On the paper plan or top view, the two legs need to be in line to each other within .007. Should I use profile or parallel or what? No datums.

 

[ctopher]

My guess would be parallel. How do you inspect it?

Chris
SolidWorks 11
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SolidWorks Legion

 

[powerhound]

Is the top view a circle or a rectangular shape? If it's rectangular and if you are saying that you need the front face needs to be parallel to the back face then parallelism is the right callout; however, you need a datum to specify it correctly. If you just don't want to use datums then a note saying "FRONT FACE MUST BE PARALLEL TO BACK FACE WITHIN .007" TOTAL" may be sufficient.

If the top view is a circle then I'm not understanding the question.

John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

 

[learningchecker]

Hi, Thanks for responding. The top view shows the horizontal rectangular legs. The 15 degree leg in the plan view (front view) is hidden in the top view. This is a torsion spring. I'll parallelism. Thanks for the help.

 

[pmarc]

Keep in mind that parallelism never controls distance between surfaces of the legs. So the two surfaces may be parallel to each other within.007, but their mutual location will stay uncontrolled. Profile of surface doesn't have this limitation.

 

[drawoh]

learningchecker,

Both parallel and profile tolerances relate the feature to some other feature. How can you not have datums?

A profile tolerance will control the actual deviation. All parallel does is make the deviation approximately constant. Profile tolerances also control parallelism.

--
JHG

 

[learningchecker]

I ended up using profile and adding datum A. Thank you all for you thoughts.