Perpendicularity

[Sa-Ro]

How to define perpendicularity to opposed feature in single FCF.

ref attachment.

I used to attach individual perpendicularity FCF to each surface.

 

[chez311]

Your figure shows perpendicularity controls which control the perpendicularity of the midplane (FCF attached to dimension) and the surface (2X FCF attached to either surface, offset from the dimension). These are not equivalent controls.

If your desire is to only control the perpendicularity of the 2X surfaces the notation "SURFACES INDICATED Y" could be utilized (similar to your question on your other post). Multiple leader lines from a single perpendicularity FCF could also be an option since you are applying it to the surface.

 

[drawoh]

Sa-Ro,

This actually is a good question. I am looking at ASME Y14.5-2009. Your standard may be different.

Section 6 is Tolerances of Orientation.

Perpendicularity is the condition of a surface, feature's center plane, or feature's axis at a right angle to a datum plane or datum axis.

All of the perpendicularities in the standard are shown with diameter symbols. They control the centre axes. Your second figure with the taper correctly shows an acurately perpendicular axis, with a sloppy diameter. If it matters, you can specify zero perpendicularity at MMB.

I have no idea of how this works in the ISO standard.

--
JHG

 

[chez311]

Sa-Ro,

Can we get clarification if you are talking about a cylindrical or planar/width-shaped feature? I saw the wording midPLANE and reference to opposed features, as well as lack of diameter symbols in the FCF's, all of which implies a planar/width-shaped feature. After drawoh's comment I notice was almost seems to be a diameter symbol on the 50 width, but also seems to be scribbled out.

If you are instead talking about a diameter on a cylindrical feature I have no idea what "opposed features" you are referencing. You would have to clarify this in that case.

 

[greenimi]

I have to recognize I have a strong competition in asking confusing questions / poorly worded questions:

RE :"How to define perpendicularity to opposed feature in single FCF."
What that means?

How to define perpendicularity to opposed feature in single FCF.

Sa-Ro,
In order to answer your question, could you please, rephrase it!
What exactly you are trying to define?

 

[Sa-Ro]

It is a width feature only.

Two side faces to be controlled for perpendicularity in plane. Not in diameter shape.

 

[Sa-Ro]

I would like to control the perpendicularity of width shaped feature wrt bottom surface.

Is it necessary to apply individual FCF at each surface or any other method to apply single FCF and denote number of surfaces.

I hope now my question is clear.

 

[Sa-Ro]

FCF attached to the size dimension is for example only.

To control the perpendicularity of the both surfaces wrt same datum, till date I used FCF attached with size dimension with perpendicularity symbol.

So I just drew that also for discussion.

By referring GD&T tutorial I came to know that, FCF attached to size dimension will control only midplane, irrespective of the side surfaces. So my intension is not represented in drawing.

 

[greenimi]

Re:"I would like to control the perpendicularity of width shaped feature wrt bottom surface."

Speaking strictly about perpendicularity of the middle / center plane:

I would say the center plane of the considered feature must lie within 0.1 tolerance zone regardless of the tab's size. The total width tolerance zone is between two parallel planes oriented perfectly perpendicular to datum plane A. The sides of the tab are not controlled for perpendicularity directly to the datum plane A, except thru the stack-up (size and perpendicularity of the center plane)