Typ, Both Sides and Other Notes

[ModulusCT]

I've attached a pdf of a drawing that shows what I'm talking about.

A hole is dimensioned to a feature that is mirrored on the other side of the part. Is it appropriate to say "BOTH SIDES" or "TYP" to indicate that the dimensions apply on the other side of the part where the feature and hole relationship are mirrored?

Using a CL would be inappropriate because the part is not completely symmetrical.

Any help is appreciate.

 

[KENAT]

Do not use TYP - this has been discussed on here several times. It isn't in any of the last few editions of ASME Y14.5M and while most people think they know what it means I've seen a few conflicting versions.

If you have 2 of them say "2X" or if you must "2 PLACES".

Make it explicit, the 94 version says to use "X" in this application.

Or, draw your leader line across to the other hole. Leader line may not be quite the right term, I forget, but I think my point is obvious.

Functionally, is it really the distance from the ends of the 2 'tabs' that's important?

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[ModulusCT]

Functionally, yes, I believe the location from the outside of the arm is important. Those holes are for mounting an electrical connector to this hunk of metal and the tabs must fit within cutouts on the connector.

 

[ModulusCT]

Oops, I forgot to ask my question, Kenat.

Is it common practice then to say 2X and have it understood that it applies to the similar feature on the other side of the part?

I thought that someone had told me years ago to use 2X only if the 2nd feature is directly in line with the first... Which would not be the case for the dimension taken across the arms width.

What do you think?

 

[KENAT]

On the .205 I think you're fine, it's obvious and '2X' should be fine.

On the .150 (which I didn't notice first time) I'd suggest explicitly dimensioning the other hole. 2X or any variation would leave it slightly open to interpretation if you meant from the left or right face.

Always remember that drawing should be explicit and not open to interpretation as much as is possible.

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[PeterStock]

Use 2X if you think the intent is clear. If you have any doubt or if you think the vendor will call to clarify the intent, show both dimensions. The dimension shown as .150 TYP is one I would show in both locations, it is not clear with side the .150 is from in the other location.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net

 

[PeterStock]

GTMA Kenat

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net

 

[ModulusCT]

Thanks... Issue resolved as far as I'm concerned.

 

[ewh]

someone had told me years ago to use 2X only if the 2nd feature is directly in line with the first

This is not the case per Y14.5 (but may be the case in a separate company standard). All that is required per Y14.5 is that the feature dimension(s) are the same.
The standard no longer explicitly prohibits "TYP", but is is generally accepted that this is poor form, and the number of places should be used instead.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[MartinSr00]

Yeah, TYP is bad news.

It doesn't let you know how many "TYP's" there are.

 

[fcsuper]

Both sides may indicate front (facing) and back side instead of mirrored left/right. So, I wouldn't use that here.

I personally don't have a problem with TYP (it does have uses that I've never seen fully addresses by those in the absolute "no" camp), however in this case, there's no point. Just use the standard 2X. On .205 dim, you don't even need that if you place and extention line connecting the two holes.



Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[MartinSr00]

Here's an idea.

It appears you have a parting flange. Simply put a note pointing to the parting flange stating "2X PARTING FLANGE"

Then on your note with the holes, put the note "6X Blah Blah Blah, EACH PARTING FLANGE"

 

[ctopher]

You can actually type "Blah Blah Blah" and it would go unnoticed. I have tested it.



Chris
SolidWorks 09, CATIA V5
ctopher's home
SolidWorks Legion

 

[PeterStock]

One drafter I worked with claimed he put a happy face on a drawing and it made it through check. They had to ECO the drawing to remove it.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net

 

[KENAT]

Peter, it used to be de rigueur to try and slip stuff past checking, the 'Kilroy' character was a favorite so I've been told.

Here people used to put the logo of their favorite sports team or similar little things on their drawings. Of course, given they didn’t have checking I’m not sure of the reasoning.

Given that checking is a thing of the past in so many places it’s not really a challenge or test to put something on a print so what’s the point.

Posting guidelines faq731-376

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(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[fcsuper]

KENAT is right. Often, responsible engineers don't even look at the print or bother to understand the change before approving it with a simply click of the button in the PLM.

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group

 

[pierdesign]

agree that TYP is bad. Especially as today had to deal with global electronics company drawing bristling with TYP next to basic dimensioning, too late as PCB files are out so now we have hole pattern that may not fit connector.

To try and add something new...

In a part like example shown, planar faces with lots of holes, and being fortunate to see many companies' drawings and talking to many fabricators, I resorted to lettering holes and referencing the letter in the dimension.

In example here, I would put a letter B beside each hole, dimension would read .205 2X 'B' / .099 4X 'B', hole callout includes 6X...INDICATED 'B', and so on with all other holes.

Numerous examples where this has aided in discussions, problem resolution, as well as fabricators indicating it's useful for them.

My Standard copy is conveniently on loan and I just don't remember if any comment on this type of practice, it's certainly not new.

 

[KENAT]

I believe it is in 14.5 somewhere though the last time I tried to find it I couldn't. I believe 'indicated' is even the preffered verbage, though half the time I forget and say 'marked'.

I use it quite a bit when I have multiple hole patterns that coule be confused with each other, for instance if they are the same or similar sizes.

Posting guidelines faq731-376

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(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[ModulusCT]

I use indicated holes all the time...

 

[fcsuper]

TYP is useful when there are no discrete quantities.

One example may be if you have a series of meandering and braching channels where multiple depth and width dims may actually be more confusing than helpful, and where a qty would be based on POV on how one sees counts a branching channel's beginning or ending.

There are many bad places to use TYP, but there are a few legit uses for it that are not well covered by the standard.

Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group