Find Number Ballons - Quantity Required 2

[moebius4]

ANSI Y14.100 and DRM state to use QTY REQD next to a find number ballon to indicate the quatity for the callout in the body of the drawing. We all agree to this practice here. Ex. For an assembly that requires a bolt, two washers and a nut, we would show 3 stacked ballons with "2 REQD" next to the find number for the washer.

Where we have an argument is how to show that this combination is in multiple places in the assembly. One camp wants to bracket the stacked balloons and but the number of places this occurs as "3 PLACES". Another camp agress to the bracket but wants to use "3 REQD". A third camp says no bracket, just put "3 PLACES" underneath the stacked balloons. (My preference)

Nobody can find any ANSI or global specification that specifically address this. If none exist I say add one of these methods or something similar to our local specification to end all of this bickering. All three camps want it their way. If someone can point to a recognized spec we can end this now.

 

[MadMango]

Per ASME Y14.100-2000, D8 Find Numbers, find numbers "may be assinged to an item for the purpose of cross-referencing an item identified in a Parts List (PL) or table on the drawing...." Due to this purposeful cross-referencing, we always couple our ballooned find numbers to a Parts List on the drawing. The Parts List defines the QTY required, and we do not add additional "3 REQD", "3 PLACES", or "3X" next to our balloons, as it would be redundant.

As for addressing the multiple places on the assembly, if the location of multiple fasteners or items is not clear, we add additional balloons as required.

 

[moebius4]

I have a feeling that there will not be a specification that addresses our situation. Many of the ASME (sorry wrote ANSI in my original post) Y14 specifications allow for a wide variance, and need to. Probably going to be a company unigue process.

Our separate groups that develop drawings agree on using QTY REQUIRED next to find number balloons. Just not on how to show multiple loctions. If the other multiple locations are not evident, we do use additonal find balloons.

If you're attaching an electrical connector to a panel it would be quite clear that all 4 corner holes will get the same hardware. But you might attach something else using the same kind of washers and nuts but with a longer bolt/cap screw and your P/L quantities wouldn't be so clear for the washers and nuts. Indicating multiple locations allows for the drawer and checker to tally up all of the hardware and make sure the P/L quantities are correct. We have CAD personnell that still do drawings with AutoCAD and they must add up the hardware quantities.

 

[MadMango]

If QTY REQD must be shown, I would just use the "3X" notation.

 

[ctopher]

I agree with MM. Use "3X".

Chris
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[moebius4]

That part is not an option nor is it a problem here. Our drawing policy includes the Drawing Requirements Manual (DRM) issued by Global Engineering Documents which specifies in Sections 7.10 and 7.11, and have been referenced and interpretted by each group here as to why they would use "X REQD" next to a find number balloon. It's not required, but if used it should be as "X REQD". We use to use the format "3X" next to find number balloons but stopped when the DRM was added to our policy.

We would and do use 2X or whateverX with dimensions to indicate it applies to two or more features.

I appreciate your input and what you all do at your businesses, but your responses don't apply to what I'm trying to find out. My original post includes a PDF of the three representations. The bracketed 3 REQD and 3 PL, or the 3 PLACES under the stack are the points of disagreement, not the use of 2 REQD next to the find balloon.

 

[MadMango]

You misinterpreted my post, I was saying to use 3X instead of the 3 PLACES notation in your example. Sorry if that wasn't clear.

The problem is I don't think an ASME standard exists that covers this. As you stated, you will probably have to create your own internal rule. I have never encountered brackets associated with stacked balloons before as illustrated in your PDF. I find that they are very confusing and could add a lot of clutter to a drawing. I also would not consider the Global Engineering Documents to be a true "standard". It may be based upon ASME, old ANSI, and probably the General Electric DRM, but it is not a defacto standard like ASME or ISO standards.

I would recommend that you use no brackets for your stack of balloons, and under the stack I would use (3X) as a reference for the number of instances for the stack.

It's Christmas Eve, go and enjoy it!

 

[Tunalover]

There doesn't (and shouldn't) have to be a standard or book somewhere that says how to do it. Good practice says to use multipliers in the form of X (not PLACES as that is not universally understood) with braces or brackets to logically group items together before applying a multiplier. You can even say 3X 2X to indicate that three items are required in two places. For example, the screw, lockwasher, and flatwasher used to mount a six-hole PCB would have a brace around those three balloons then a 6X multiplier applied to the brace.

Drafting is a lot more forgiving than many think. People go off with the impression that there's a "right" way to do it when in fact there are several if not many ways to do it all being equally legal.



Tunalover

 

[ctopher]

Tunalover,
I have never seen "3X 2X" used.

Chris
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[ewh]

I have often used a bracket as in the first two examples; however, I use "X" throughout, no "PLACES" or "REQUIRED".
I have to disagree with MadMango regarding the Global Engineering Documents not being true "standards". If your company specifies it in a quality manual, it is then the defacto company "standard". While tunalover is correct in that there are many right ways to do something, if a standard such as Global's or GE's is specified as the company standard, they would determine the correct way for that company.
It is not very important how you denote things like this, but it is important that your method be consistant.

The Edge... there is no honest way to explain it because the only people who really know where it is are the ones who have gone over. - [small]Hunter S. Thompson[/small]

 

[ctopher]

Check out, 4.2, Fig 17:

http://mscweb.gsfc.nasa.gov/543web/files/GSFC-X-673-64-1F.pdf

Chris
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[aardvarkdw]

Why wouldn't you just write:

(12) 3X
(16) 6X
(19) 3X

"()" represents find number balloons.

Or "x"REQD if you prefer instead of the method described in ASME Y14.5M-1994, but that is a different argument entirely.

This accurately details the number of parts used and in what configuration so that there is no confusion. I would be concerned that by using brackets there could be ambiguity and misinterpretation, especially if you are using differing terminology inside and outside of the brackets (REQD and PL).

FWIW, I would not use "PL" at all as it has 10 different approved definitions per ASME Y14.38-2002.



David

 

[Tunalover]

ctopher-
Using a "3X 2X" notation in many contexts is more meaningful than "6X". Because you haven't seen it doesn't mean its invalid. My position is this: the practice is more informative and there's nothing within Y14.100 that says it should be avoided. Why over-restrict things?


Tunalover

 

[ctopher]

Tunalover,
I didn't insinuate it was invalid, just never seen it before.
It does not make sense to me either. I follow standards that are required by gov't and space orgs. A lot of companies do not and follow their own ways.
The way aardvarkdw shows makes sense to me.

Chris
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[KENAT]

moebius4 my checker and I went around the bushes on this a couple of years back and weren't able to find anything definative in the ASME stds or as I recall in the Genium (old GE) manual.

We ended up just putting the following in our DRM.

"Item quantity shall only be shown in the parts list and not in/by the balloon except if for clarity the number of items used in a specific application on the drawing is needed, then it shall be added as a note; however, this practice shall be avoided where possible."

"Typically each different application of a part on an assembly shall have a balloon (using the same item number)."

By note we mean "3X" or similar next to the balloon.

I've seen the bracket used a lot on drawings in the UK for this type of situation.

On things like this I try to go by what is the clearest/least ambiguous within the range allowed by the standards. Definitely be consistent within each drawing and as much as possible across all drawings created by the same 'authority'.

I too would avoid "PL" as it has so many meanings. I'm not a fan of REQD either but appreciate you invoke a spec that requres it.

Of your options I'd probably pick the bottom one (it's similar to how we do it but with X instead of REQD), especially unless you have a good way of auto generated the 'bracket' with your CAD system. I actually like the use of 'PLACES' spelt out for the 'set' to differentiate from the X or REQD for the individual items, so long as everyone reading the drawings understands English.

To me the 3X 2X could be confusing and any of your options are clearer.


KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[moebius4]

Appreciate everyone's input. Looks like this will come down to a majority vote here and be added as a local requirement.

My #1 goal is be clear, concise and unambiguous.

I will recommend that if we can't reach a satifactory agreement on how to indicate that a set of balloons occurs at obvious multiple locations, that we repeat the balloons at each location rather than using X PLACES underneath or brackets to the side.

 

[ctopher]

Repeated balloons nead to be shown as reference.

Chris
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[ewh]

No, "REF" would be required only if that item is accounted for elsewhere.

The Edge... there is no honest way to explain it because the only people who really know where it is are the ones who have gone over. - [small]Hunter S. Thompson[/small]

 

[KENAT]

I've had the same argument with a colleague and I agree with ewh. Especially if it's the same item but used in a completely different application then making it 'REF' doesn't really make sense to me.

I know there are places that do this though.

That said, too many repeated balloons can make a messy drawing which is why we try to avoid it.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

 

[fcsuper]

for me, I usually show one grouping (that is obviously a group for whatever reason [such as an obvious pattern]) gets the full quantity for the entire assy, then I balloon the same part at other locations, but place a (REF) next to it.

Matt Lorono
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