Runout Symbol Question 3

[CTengineer2012]

The attached drawing clip is from a rotor machine drawing and I have the following questions about the run out on this rotor:

1) Which symbol represents the run out on the vertical face? Which symbol represents run out on the rim? Is perpendicularity the same as runout on the face? My machinery handbook has a different symbol for run out and it is not seen on this picture.

2) What is the symbol with the circle-dot and F.I.R. beside it?

3) Is the face run out tolerance .0005 or .001 on this rotor based on this clip?

Please list references for responses so that I may look them up myself.

Thanks

http://files.engineering.com/getfil...e-e194-4a3b-b8fc-16fe29156f5d&file=Runout.jpg

 

[CheckerHater]

There is absolutely nothing about runout on your drawing.

 

[powerhound]

This is an old print. It would not surprise me if it was made in the 50s. There is way too much information alcking from your post for anyone to really be able to answer your question. We need to know how this functions in order to give you our opinion on how to tolerance it.

My answers to your questions are:

1. A total runout symbol is the one with two arrows pointing to the top right. Circular runout only has one arrow.
2. The circle-dot symbol may be an old version of runout considering it is referencing FIR which stands for Full Indicator Reading. It looks more like concentricity though but there's no provision for straight FIR as it is currently defined.
3. As CheckerHater said, there is no reference to the modern version of runout so there's no real answer ot this question. You have a perpendicularity call out and what appears to be an arc length callout but that would make no sense so maybe it's a profile of a line callout that's just poorly drawn.

John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

 

[CTengineer2012]

It's for a GE frame gast turbine. Yes it probably was made somewhere around 1960-1970. Can't really see any dates on the drawing. The coupling I am referring to is the marriage coupling between the compressor and turbine rotor. I have set the tolerance for the axial run out on this face to .0005". We machined it down to .0004" successfully and that's what we're going with. I was just trying to learn about the symbols on these drawings as I have never had to deal with them.

Thanks for your help.

 

[SeasonLee]

The circle-dot in a circle symbol in an old version of concentricity in 1963 MIL-STD-8C.

Season

 

[Belanger]

To answer the very first question ... what controls the "runout" of the vertical face is actually the perpendicularity callout of .0005 (presuming that datum A is an axis).

What I mean is that if you substitute the total runout symbol for perpendicularity, it would have the same identical meaning. As mentioned already, this print doesn't use the runout symbol, but I'm just pointing out that in this case they have the same effect.

The circle-dot may be an old symbol for concentricity, but the fact that it says FIR means that it's not the same as concentricity as we know it today, because FIR implies that form is also being controlled.

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

 

[CTengineer2012]

So if I was to look at this print to determine the maximum run out on the vertical face of that flange, I would use .0005" because of the perpendicularity reference there. That's fine, I used .0005" as my tolerance and we got the vertical run out on the face down to .0004". However, I don't totally agree about the perpendicularity being the same as run out on the vertical face of the flange. Yes if the perpendicularity of the face with resepect to the "A" axis is off, then the run out will show this. However, to me, it seems like the perpendiculartiy would not take into account the high spots on the face.

 

[Belanger]

Perpendicularity will indeed measure the high and low spots on the face. When perpendicularity is applied to a surface, it automatically controls the flatness of that surface (unless a circled T is invoked). However, the degree to which those high spots are discovered will certainly depend on the diligence of the inspection process.

Also, as a side not, runout is a pretty broad term. In GD&T parlance there is "circular runout" or "total runout." In our case, perpendicularity is identical to total runout (a double-arrow symbol).

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