Runout - Shaft with Notch

[JLang17]

I have a cylinder shaft with a small flat notch on it roughly centered about the length. I am applying a total runout tolerance to the shaft.

In the drawing view, the shaft is layed out horizontally and the notch is shown on the top surface, while the bottom surface is shown as one continuous line.

How do I specify that the runout applies everywhere but the notch? Or is this implied? Do I need a FCF on both sides of the notch? From what I could find, ASME Y14.5-2009 doesn't talk about breaks in the surface where a runout is applied.

 

[KENAT]

If you apply the runout to the diameter, and the notch isn't the same surface then I'd think it was clear, but I'm not sure I followed all of what you posted.

KENAT,

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[drawoh]

JLang17,

If the face to face tolerance is more important than the centreing of the notches, you can apply a positional tolerance to the dimension.

JHG

 

[dingy2]

It is understood that the total runout is on the full surface of the shaft including the area around the notch but not the notch itself. Don't do anything tricky; just show the surface with the total runout value that is needed.

Dave D.

http://www.qmsi.ca

 

[JLang17]

Thank you dingy2, that's exactly what I needed to know. I wasn't sure if that was assumed or if it needed to be clarified.

 

[powerhound]

If I understand the post correctly, what are you calling out the runout to? You must specify it to a datum. If you simply have a shaft, what will be your datum?

Powerhound, GDTP T-0419
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Inventor 2009
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[dingy2]

Good point powerhound. If the shaft does not have countersunk ends where datums could be created, then one would place a cylindrical value on the OD and it is to itself.

Cylindricity combines roundness, straightness of an axis and straightness of a surface.

Dave D.

http://www.qmsi.ca

 

[JLang17]

The shaft is my datum and I was referencing the runout to itself. But yes, cylindricity would accomplish the same thing I suppose.

 

[dingy2]

You cannot use circular or total runout in your situation since you are referencing the OD. Cylindricity is your only option here.

Dave D.

http://www.qmsi.ca

 

[JLang17]

I thought it was legal according to ASME Y14.5-2009 para. 9.5.5: "runout tolerance may be applied to a datum feature and related to the datum axis derived from that datum feature"

I'm applying runout to datum feature A (shaft), thus relating to datum axis A (shaft axis).

 

[dingy2]

First of all, you are probably the only person here who is now using ASME Y14.5 - 2009 and I hope that your drawing reflects this level in notes. Watch out for datums at MMC though since these are quite different from the 94 standard and if you reflect a feature control frame in degrees of freedom, it would blow the minds of the shop floor people. I hope that everyone in your company is well acquainted with all the new changes.

That being said, the 9.5.5 refers to figures 9-6 & 9-7 which are the same examples used in the 94 standard. We have the datum axis derived from 2 features and the circular runout is required on one of the features.

Your example is to itself and not 2 features. I know that the words in 9.5.5 say this may be legal but the example reflects something different. I, again, would reflect the OD with cylindricity since it is well understood.

Dave D.

http://www.qmsi.ca

 

[JLang17]

I am now curious to the words used in the '94 standard that refer to the same examples. I'm inclined to think the words would take precedence, otherwise they'd need x amount of examples for every paragraph to fully clarfiy what can/can't be done.

I do agree that cylindricity would be better understood here.

As for my company using the 2009 standard, the drawings absolutely reflect that and our manufacturers are working with us as we progress into the GD&T world. Most of this is actually new for them as well.

 

[dingy2]

JLang:

I would NOT recommend the 2009 standard in my drawings at this time. It is WAY too complex and you would be better off using the 94 standard especially since everyone is new at GD&T.

I have been training in this subject for over 20 years and will not incorporate much of the 2009 standard changes into my basic GD&T seminar. In the Advanced seminar, I will get into degrees of freedom, calculating MMBs depending upon whether they are primary, secondary or tertiary, MMC application to profiles, etc. but it is heavy.

As I stated, go cylindricity and apply the same tolerance as you had in mind for the total runout.

If your company and your suppliers are new to GD&T, get some training and then find someone who would be your GD&T guru for ongoing consultation. Make sure that everyone in your plant who will be using GD&T receives the same training. The danger is that you could be putting something on a drawing that you may not understand and cost your company a lot of $$. On the other hand, one could end up with conflicts on the drawing and could lead to a part made to specification that may not function. BIG MESS!!!



Dave D.

http://www.qmsi.ca

 

[JLang17]

Well my company is just beginning to move toward GD&T. So by the time it is fully implimented, perhaps the 2009 version will be more commonly used. Our manufacturers are within the same parent company and they are learning along side myself and our engineers, based on the 2009 standard.

I'm just the CAD guy though, so I don't have much input on what our company decides to do...but I see no reason for us not to adhere to the '09 standard.

 

[JLang17]

That being said however, please give me reasons why we shouldn't learn based on '09. I think the idea was to use the latest and greatest. Training is yet TBD...

 

[dingy2]

There are some companies that are still using the 82 standard for some reason but most use the 94 standard which has a few changes from the 82 level. The 2009 level is complex with many changes and your initial application of total runout to itself is a perfect example of misapplication and it would blow everyone's mind.

I would suggest training to the 94 standard and then, maybe, in a couple of years converting to the 2009 standard. It is a complex standard relative to the older standards with some typos and other errors in the initial printing.


Dave D.

http://www.qmsi.ca

 

[PeterStock]

I do not know if anybody is teaching the 2009 standard yet. That being said, if your company and it's suppliers are just getting started with GD&T and can get training in 2009 then going straight to the 2009 standard may make sense rather than change again in a few years.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services