Profile question

[botrott]

I have seen a drawing that has Basic Dimensions going to two different depths and the overall length of the part but no Feature Control Frame to tolerance them. In the note section the drawing does have a note that says "Features in the electronic data file are basic with a profile tolerance of 0.010 to Datum A, B, & C." Is this allowable or should there actually be a Feature control Frame?
Thanks,
Botrott

 

[fsincox]

Conceptually yes, Are datums A, B & C on the drawing? Tolwerance is pretty tight unless it is a small machined part. Naturally we need to know more, but the idea of a default general tolerance and using the model dimensions is the comming thing, probabaly should be "dimensions" in the model not "features".
Frank

 

[KENAT]

I'd say 'Geometry' rather than features or dimensions, since the model may not have dimensions.

I think Y14.41 says a little about it but I don't have time to look now.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[MechNorth]

If your question is whether the general tolerance surface profile can be written in text rather than in a proper feature control frame, there is nothing in the standard that precludes it, and the Y14.5 standard does say that notes can be used to clarify. Though it may not be technically incorrect, it's still bad practice.

Jim Sykes, P.Eng, GDTP-S
Profile Services

http://www.profileservices.ca

TecEase, Inc.

http://www.tec-ease.com

 

[flash3780]

I've seen casting drawings which specified a general tolerance from defined datums relative to the solid model nominals. More critical dimensions were toleranced explicitly.

Some places are even getting rid of drawings completely, notes and GD&T are instead called out in views of the solid model.

The times they are a-changin'