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CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

(OP)
See attached. I guess the answer is NO. Just want to confirm.

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

I would say so, I can't see the example, interuppted like a keyway or like (2) bosses?
Frank

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

Strictly speaking I would say no but if you ignore any readings near the interruptions then you could get a quick & dirty measurement. The problem is going to be deciding when is the indicator movement due to an irregularity in the surface and when is the probe tip falling into the gap.

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

Again I say: the reason I do not like runout is people think of it as a process/method and not a just a tolerance specification, this is a perfect example.
Frank

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

CH,
May I know which book/article does this picture come from?

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

CH,
That takes me back to my old machine tool days!
Frank

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

Per the 2009 standard, circular runout can be applied to less than a 360 degree surface of revolution. Total runout is still 360 degrees though. Compare the 1994 definition of circular runout to the 2009. You will see that the wording has changed to allow for less than 360 degrees.

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

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

OK, That is where I had seen this before, I have that book!
Frank

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

In my opinion there is nothing wrong in applying runout (circular or total) to circumferentially interrupted surfaces of revolution.

As for the picture from G. Henzold's book... well, by definition (ISO or ASME) any kind of runout must involve datum axis. I think that speaks for itself.

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

The picture from G. Henzold's book shows real-life functional requirement.

The fact that neither ASME or ISO is capable to satisfy the need speaks for yourself as well... sad



















9

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

Quote (CH)

The picture from G. Henzold's book shows real-life functional requirement.

So could you please explain the functional requirement to me?

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

Shaft running parallel to a plane, I believe.
Frank

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

I can finally see the attachment.
And I don’t see any problem.
It could be simpler if datum A was just one flat side of the “thickness”.
Yes, and don’t forget both A and B should be referenced RFS.

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

I do not see any problem, either, looks like a motor rotor lam.
Frank

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

The problem I have is that when you make a full revolution the indicator tip will fall into the surface interruptions and you will obviously have indicator movement beyond the spec. So it becomes a judgement call of when do you start and stop reading the indicator. As long as you stay away from the interruptions it is OK but what if you have some surface deviation near an interruption? You could either pass a bad part if you don't pick it up or reject a good part if you get into the interruption. Probably OK for a quick and dirty check but not something I would want to do for serial production.

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

dgallup,
Your concern is reasonable, however I would say this problem may happen even when actual runout error of simple regular cylinder is inspected. Picture a shaft comprised of two cylinders - one is datum feature, second is toleranced relative to the first with total runout. In most cases there will be a fillet between the two cylinders. So during the inspection there will be also a possibility that dial indicator will go beyond toleranced cylindrical surface, touch the fillet and in consequence the reading will be distorted.

Bxbzq's part does not have to be inspected by continuous rotation 360 degrees around datum axis. This can be done slice after slice. The key thing is just to make sure that the readings are not zeroed between the slices.

Frank,
If the functional requirement on G. Henzold's picture is to keep the shaft parallel to datum plane A, why not to apply parallelism tolerance?
If the functional requirement is to keep the shaft parallel to datum plane A and located from datum plane A, why not to apply position tolerance (with possible refinement of parallelism, if needed)?
Why would somebody want to check circular runout in this case?

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

pmarc -- your suggestion of parallelism on that shaft would not be able to detect circularity errors; that's the only hitch that I see.
A runout tolerance on that shaft would control the entire form (cylindricity), as well as orientation (parallelism), and location (although only height location, not coaxial location as intended by runout). No other control can do just those three things (not even profile).

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

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

J-P,
Of course neither location nor parallelism would be able to detect circularity errors. But do you really think that assembly level drawing is the proper place to check circularity error of the shaft? In my opinion this is one of the characteristics, apart from shaft size tolerance, that can be easily provided by engine manufacturer without necessity of simulating working conditions of the engine. Besides, even if there was a need to check the circularity, why not to apply direct circularity callout in addition to position and/or parallelism callouts. Why to make up callouts that are not supported by any standard and actually (in my opinion) does not reflect functional requirements?

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

Sure, an assembly drawing can be the proper place to note this requirement -- maybe I'm contracting a company to make this thing and all I care about is the final function. It's not my job to detail all the sub-assy parts for them.
Granted, the current standard doesn't really allow for this use of runout, but that's why we're discussing it; to see if there is even any legitimacy to trying for such a use.

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

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

Okay, say you are contracting a company to make this thing for you. Why would you like to go with the runout callout instead of clear combination of position tolerance (possibly with addition of one more datum reference) and circularity tolerance?

Please do not get me wrong. I am all for novelties and extension of principles, but only if there is really no other way to express something. Per my understanding we do not have such a situation here.

RE: CAN RUNOUT BE USED ON A INTERRUPTED DIAMETER

I agree, but if we really hold to that thinking, then there's no need for the symbols flatness or perpendicularity, since they can already be accomplished with profile of a surface (or even angularity, in the case of perpendicularity).

But I know what you're saying -- and at this point it's really just an academic discussion :)

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

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