Position Tolerance Usage

[cascadco]

Does anyone know, postion tolerance usage tips.

For example I know using for hole positioning.
But attached symbol used for surface, what does it mean?

Best regards.

 

[ctopher]

Some info:

http://www.tec-ease.com/tips/august-99.htm

http://toolingandproduction.com/archives/0205/0205bonus_tolerances.asp

http://www.engineersedge.com/gdt.htm

http://www.verisurf.com/gd&t.htm

ftp://arrow.delcam.com/pub/pdf/brochures/PI%20Manual.pdf

I suggest having the ASME library at your business.

http://store.asme.org/category.asp?...category_name=Drawings+and+Terminology&Page=1

Chris
SolidWorks 08 0.0/PDMWorks 08
AutoCAD 06
ctopher's home (updated 10-07-07)
ctopher's blog

 

[KENAT]

cascadco, take a look at some of the links Chris gave you.

Also

http://www.roymech.co.uk/Useful_Tables/Drawing/draw_geom.html

has a little.

According to ASME Y14.5M-1994, the US Dimensioning& Tolerancing standard:

"2.1.1.1 Positional Tolerance Method. Preferably, tolerances on dimensions that locate features of size are specifieed by the positional tolerance method ..."

So it's not just holes although that is perhaps its most common application.

Without seeing the 'surface' that FCF was pointing to on the drawing it's difficult to say what it meant. The fact it doesn't have a diameter symbol means it's a square position zone rather than circular as often used with holes, if that helps.

KENAT, probably the least qualified checker you'll ever meet...

 

[axym]

In Y14.5, the Position characteristic controls extracted geometry of "features of size":

-Axis of a cylinder
-Centerplane of a slot or slab
-Center point of a sphere

That's it. There is no application of Position to surfaces. Location control of surfaces is accomplished using Surface Profile.



Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[powerhound]

This FCF would almost certainly have to be located under a toleranced dimension. I can't think of an instance where an arrow would point to a feature and this be legal. In fact, I can't think of an instance where you would reference 3 datums and not have a diameter symbol preceding the tolerance value. Maybe it's just sort of late and I'm not thinking enough.

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