Does this seem backwards?

[Sl33stak]

I'm programming a part for one of our subs, and their print calls out PERP. of a plane back to a through hole. Is that odd? I'm used to the through hole having its PERP. called back to a plane. Note the other way around. This is their way of controlling the paralellism of two of the planes.

[#2#]

Seems odd to me. Not necessarily wrong but probably not the best way to do it.

[craiger_ny]

Perhaps the face is the moving part and the through hole gets a shaft mounted in it to rotate the whole thing. In that case it would be dimensioned as it is applied. That is the real question, is it dimensioned as it is applied? There is no convention that says you control this to that. How you control your features depends on the parts usage. If the part is to be stationary and a rotating shaft goes through the hole then I'd say yeah it is backwards but if the part gets mounted to a rotating shaft and the entire part moves then you would probably want to control runout of the face and I'd say it is dimensioned smartly. What is the application?

Craig

[Sl33stak]

The funny thing is I have no idea what the parts function is! I DO know that the two faces that I am questioning are mount surfaces, and that something (maybe a porpoise or llama) runs through that hole they are supposed to be PERP. to. ****, it's Friday and I'm burnt out.

[#2#]

The funny thing is I have no idea what the parts function is! I DO know that the two faces that I am questioning are mount surfaces, and that something (maybe a porpoise or llama) runs through that hole they are supposed to be PERP. to. ****, it's Friday and I'm burnt out.

Since porpoises don't run I'm going to guess a llama!

Here you could use this.

TGIF http://www.pcdmisforum.com/showthread.php?t=1768

[Sl33stak]

So how exactly do I do this? Do I call my cylinder the origin, then call out perp. of my plane? I get crazy numbers that way.