Use of composite geometric positional tolerancing on cylindrical surfaces 1

[Tunalover]

Is this possible? I see cases where a hole pattern can float as a group on a cylindrical surface but the in-pattern positional tolerance must be controlled to insure fit. How would one establish a datum reference frame for this scenario? TIA.

Bruce


Tunalover

 

[pmarc]

A sketch could help. Can you post anything?

 

[Tunalover]

pmarc-
I'm not at work and won't be in the foreseeable future so I have no sketcher or CAD system to use to generate a sketch. My scanner is also on the blink so I can't provide a hand sketch either.

Just think of a hollow pipe with a pattern of holes evenly spaced (same angular spacing apart) around the perimeter. The same "z-dimension" would apply to each member of the group but in a general sense I suppose it may not have to be that way.

Tunalover

 

[pmarc]

Is it more or less something like this?

http://files.engineering.com/getfil...-a8a0-4f48-b671-2df9210e68de&file=capture.PNG

It is from Y14.5-2009. The standard offers some more figures showing similar configurations and tolerancing schemes - fig. 7-42, 7-43.
In Y14.5M-1994 it shown in figs. 5-24 through 5-27.

 

[Tunalover]

Just what the doctor ordered. Thank you pmarc!


Tunalover