When should I use the FRTZF tolerance frame? 2

[BamblingBambler]

Hello,

I'm fairly new to G,D and T and I am trying to incorporate the principles in the drawings I make. I understand how composite frames work and how PLTZF and FRTZF tolerance zones are constructed. However, I am yet to see a practical example when I might want to use the FRTZF tolerance frame. The examples where I have used it so far for locating bolt patterns, I can make do with just the PLTZF tolerance zone. Are there any examples out there that I can refer to for this?

Thanks!
Sid

 

[greenimi]

Short answer for now:

http://www.tec-ease.com/gdt-tips.php;

--there are some examples here.

http://www.tec-ease.com/gdt-tips.php

Composite
Datum Feature References
Second Segment
Using a Note Video!
Several Examples Video!
Feature to Feature Control Video!
Composite l Video!
Composite ll Video!
Composite lll Video!
Composite l Gage Video!
Composite ll Gage Video!
Composite lll Gage Video!


Also the standard itself (2009)could be an excellent source of examples for what you are looking for.

 

[Belanger]

Think of an electric outlet on the wall at your home. That's a pattern of holes where both the upper and lower portions of a composite tolerance are useful. (For now let's ignore the fact that they aren't round holes...)

If I want to control the location of those holes on the wall, the overall position isn't terribly critical. I could perhaps give you a half-inch position tolerance of the holes as measured from the corner of the room. But now zoom in locally on the holes that make up the outlet: the hole-to-hole locations have to be way better than a half-inch in order for a plug to fit! Those hole-to-hole tolerances might only be allowed .080 inch.

Result -- the PLTZF would be my overall tolerance within the room: .500 for each hole with respect to datums A, B, C. But the FRTZF would be the local tolerance: .080 for each hole while only looking at datum A (the plane of the wall itself).

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[gabimo]

A shelve should be mounted on the wall with some brackets/sets of holes in the brakets. Position on the wall is more forgiving than the hole to hole pattern relationship in order for the holes in the wall to fit the pre-made holes in the brackets.
Also the FRTZF should have a primary datum feature to limit the horizotal hole alignment ( the shelve should be usable and the goods place on it should not rollover/ fall from it).