nX, Detail Views, and the INDIVIDUALLY note

[Burunduk]

Here is a figure from ASME Y14.5-2018:

And here is the definition of a pattern:

pattern:two or more features to which a position or profile geometric tolerance is applied and that are grouped by one of the following methods: nX, n COAXIAL HOLES, ALL
AROUND, ALL OVER, between A and B (A ↔ B), from A to B (A → B), n SURFACES, simultaneous requirements,
or INDICATED, where n in these examples represents a number.

So, if no INDIVIDUALLY was stated near the second segment of the positional tolerance for the small holes, does the 6X near the detail name define a pattern of 6X4=24 holes? Or would your interpretation be that every 4X holes is a separate pattern anyway, and the 6X near the detail name only indicates how many such groups are on the part?

To ask it differently, does the 6X INDIVIDUALLY note near the second segment of position break up a 24 holes pattern to 6 separate patterns (that are also controlled with ref. individual D@MMB secondary references) or does it only mean that the anyway separate 6 patterms of 4 holes are controlled with ref. to individual D@MMB secondary references?

 

[CheckerHater]

In absence of 6X INDIVIDUALLY note near the datum D, all 6 large holes become one single datum, which isn't unheard of and may be useful.

In absence of 6X INDIVIDUALLY note near the second segment of position, every 4-hole pattern must be checked against every one of 6 INDIVIDUAL datums, if that would be ever useful.

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

 

[Burunduk]

In absence of 6X INDIVIDUALLY note near the second segment of position, every 4-hole pattern must be checked against every one of 6 INDIVIDUAL datums, if that would be ever useful.

Why every 4 hole pattern and not all 24 of them simultaneously per 4X near the callout and 6X near the detail name?

 

[CheckerHater]

Because pattern is grouped by : nX.

So 4X makes a pattern.

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

 

[Burunduk]

Doesn't 6X of 6X DETAIL A also qualify as nX and create a pattern?

 

[CheckerHater]

Is there a FCF attached to "6X"? 6X DETAIL A tells us that all 6 patterns are the same, but doesn't apply any additional constrains to "patterns" or individual features.

Essentially you are asking "Wouldn't that be ridiculous if we miss some of indications required by the standard?"

The answer is "Yes, it would".

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

 

[Burunduk]

6X DETAIL A tells us that all 6 patterns are the same, but doesn't apply any additional constrains to "patterns" or individual features

Are you sure that 6X DETAIL A is different from attaching the 6X to each callout in the view?
Let's suppose that the ⌀79.4±0.1 holes were dimensioned in the main view instead of in the detail view, including the position callout. Wouldn't that require placing 6X before the diameter dimension? If yes, then since it is specified without 6X in the detail view, isn't it because the 6X before the DETAIL A notation does exactly the same thing, including creation of any pattern where applicable?

 

[greenimi]

https://www.eng-tips.com/viewthread.cfm?qid=453586

Somehow related

 

[CheckerHater]

Let's suppose that the ⌀79.4±0.1 holes were dimensioned in the main view instead of in the detail view, including the position callout. Wouldn't that require placing 6X before the diameter dimension?

NO

There is no requirement. There is a choice: place "6X" before the diameter and your datum is a pattern. Place "6X INDIVIDUALLY" nearby and your datum is not a pattern, regardless of placing the FCF on the main view or on detail view.

Now take your 3.6 DIA hole and place "24" in front of the diameter. You want to create a pattern thru simultaneous requirement as all the holes now are related to the same datum(s).
Now what the heck is your datum D? How can your pattern be simultaneously related to 6 separate individual datums at the same time (all of them being datum D off course)?

You create call-out that makes no sense, but you demand it to have a meaning. I can't help it.

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

 

[Burunduk]

There is a choice: place "6X" before the diameter and your datum is a pattern. Place "6X INDIVIDUALLY" nearby and your datum is not a pattern, regardless of placing the FCF on the main view or on detail view.

Actually, the datum is derived of an individual ⌀79.4 hole each time, not because 6X was not placed directly before the diameter callout, but because it is stated 6X INDIVIDUALLY specifically next to the datum feature symbol (and not just "nearby"). And regardless of how the datum is derived, the 6 holes of ⌀79.4 are controlled for position as a pattern. Even if from some reason you assume that the 6X near the detail name doesn't work as a usual "nX", the pattern is created due to a simultaneous requirement of the 6 holes relative to datum reference frame [A,B,C].