Diameter AVG explanation

[UchidaDS]

I am confuse about this AVG explanation. Would like someone help to clarify.
Let say I have a cylindrical part. The diameter comes with AVG notation at side.
Does this mean that it is require to measure the diameter at least at four different sections and get the average result?

If yes, if one of the section its diameter is out of the default tolerance (out of spec), but the average diameter is within the spec, does it consider pass?

 

[UchidaDS]

snap shot about the AVG.

 

[3DDave]

The example only measures at two places, but as often with inspection you need to perform enough measurements to be sure. The number of measurements is not part of the standard.

What default tolerance are you considering? The AVG diameter has a method and a tolerance; there should not be anything that interferes with that.

 

[CheckerHater]

I understand that if you simply specify AVE on round part it rather creates confusion than advantage.
Just like in your snapshot average diameter makes sense only if combined with other requirements: MIN / MAX, free / restrained state, roundness, run-out, etc.
As usual it boils down in part to "functional" requirement - how the part interacts with other parts, and in part to procedure - what you believe is reasonable way to control such requirement.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[dgallup]

"if one of the section its diameter is out of the default tolerance (out of spec), but the average diameter is within the spec, does it consider pass?"

Yes, one or more individual measurements may be out of the tolerance of the average and the part will pass. I've only done this on flexible parts that either get something pressed into another rigid part or get a rigid part pressed into them. Typically, there will be some other control on how out of round the part can be such as the circularity control on your drawing.

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[greenimi]

[The number of measurements is not part of the standard.]

The standard (1994) states at least 4

"An average diameter is the average of several diametral measurements across a circular or cylindrical feature. Normally,
enough (at least four) measurementsa re taken to assure the establishment of an average diameter."

 

[UchidaDS]

Guys, Thanks!
Yes, the reflected question comes with a roundness of .060", call out as follow:

Diam. 14.000 AVG
[O|.060(F)]

Default tolerance is +/- .005"
Using ASME Y14.5M-1994/2004.

3DDave: I just want to clarify that the section that I mean is let say I have a 1" height with 14" diameter cylindrical part.
Should this AVG apply, randomly, let say at .25" height measure the diameter, at .5" measure the diameter,...? Then take the average?

 

[dgallup]

I would make multiple measurements at a fixed height, average them for one reading then move to another height & repeat. I would not average measurements taken at different heights.

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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.