TYPICAL or TYP notation on drawings 4

[josewong]

Anyone know the exact definition for the notation: TYPICAL or TYP? I have some old drawing that use them. I'm not sure where or when to use them, or if it is even a standard. Any info is appreciated.

 

[namdac]

There should be absolutly no assumtion in what is relayed as the correct information if I call out a 3/8" hole (typ.) the machinist, manufacturer they should already understand what I am designing. If the fabricator does not understand time to get another Fabricator. A DRAWING SHALL HAVE ONLY ONE INTERPITATION. Rule no. 3
Regards,
Namdac

 

[ctopher]

Here is an example.
If you have a plate with 10 holes. Five of the hole are the same, the other five are the same. One callout indicates DIA .25 TYP, the other DIA .375 TYP. Which holes are which?
I have seen this type of drawing a lot.
The correct way would be to use a hole table.
I have also seen a part that had one hole drilled, with a callout DIA .375 THRU, TYP. The machinist wanted to know where are the other holes?
Although the new spec says it's OK to use TYP, and is widely use, I never use it for clarity.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[wes616]

My most common use of TYP is on sheet metal parts, where I have radii corners, I will usually call out one of the 4 corners and say TYP, instead of 4X or 4 PL. If I have anything else that could lead to ambiguity (sp) then I use the discrete callout method.



Wes C.
------------------------------
Light travels faster than sound. That's why some people appear bright until you hear them speak.
they found them stuffed with explosions...
[/i]

 

[TTRYON]

As I understand it. The "TYP" statement was and perhaps still is an architecture standard and not a mechanical standard. The "TYP" callout was often used in wall sections to reference typical or common elements of a section. In mechanical engineering, you often see this callout on hole dimension and the like. As mentioned in this thread, it’s not to any mechanical standard. The correct way to reference a dimension in multiple locations is to indicate the number of times that dimension is references. For example, if there are three holes then you can mark a hole as 3X.

 

[ringman]

namdac,

Do your drawings state ASME Y14.5 as the standard for interpretation. If not, and the drawing is civil, or architectural, or other, typ could be used and left to the interpretation of the users.

 

[ewh]

Even if it is to be interpreted to ASME Y14.5-1994, you could use it. The standard states in para 1.9.5):

Repetitive features or dimensions MAY be specified by the use of X in conjunture with a numeral to indicate the "number of places" required. (Emphasis mine)

Again, this does not make the use of "TYP" a best method to dimension.

 

[ringman]

ewh,

I don't believe that 'X 7' hardly equates to 'TYP'.

But if you are not applying 14.5, GO FOR IT.

 

[ctopher]

ringman,
It would be 7X.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[ewh]

It would be "7X" (... X 7 would indicate "... BY 7" and is covered in para 1.9.6), and the current Y14.5 standard DOES NOT disallow "TYP". So yopu can be applying the standard and still use "TYP". I wish it weren't so, but oh well...

 

[aardvarkdw]

The standard does not address it but I subscribe to the policy that if it can be interpreted any other way than the intended way, don't do it. I find that 99 times out of 100 "TYP" will be more confusing and draw more questions than just simply writing "(some number)X". If it is on an old drawing, that is one thing, but if you are drawing something new and you put "TYP" on it, you had better make sure that there is no possible way to misinterperet it.

 

[ctopher]

I agree.
If I am doing several changes on an old drawing that has TYP, I will request to change it from TYP. I have seen different part batches be a little different from the old drawing because of TYP from different vendors. Make it clear and don't use TYP to describe qty of features or parts.
The only time I would use it would be for example, if I'm making a custom thread and call out a thread angle. The angle would be TYP because qty of threads could vary.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[ewh]

Wouldn't you still only have one, continuous helical thread?

 

[ctopher]

Yes. But, I have had machinists question it for some reason. Adding TYP makes sense to them.
So, 99.9% of the time I do not use TYP.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[TTRYON]

Chapter 1.1 of the ASME Y14.5M-1994 standard explains the purpose of the standard.

"This standard establishes uniform practices for stating and interpreting dimensioning, tolerance, and related requirements for use on engineering drawings and in related documents..."

To me this means that if it's not in the book and you conform to the standard, then don't do it.

Section 1.9.6 indicates that an X may be used to indicate multiple locations but there is no mention of the TYP callout.

I feel very strongly that the "TYP" callout provides room for error and misinterpretation. Why would anyone use it when it is much clearer and accurate to state a multiple place dimension as 2 X or 10 X or what ever?

 

[ewh]

I agree with you TTRYON, but the previous version of the standard dictated the use of "X" instead of "TYP". The current standard only suggests the use of "X". "May" has a different meaning than "shall". The standard establishes uniform practices, but fewer uniform requirements.

 

[aardvarkdw]

I personally don't like using "TYP". Though the 1994 version of the standard uses the word "may" instead of "shall", I feel that because a previous standard prohibited the use of "TYP", and it isn't explicitly allowed in this one it shouldn't be used. In most instances "TYP" is too ambiguous and there is almost always a clearer way to say what needs to be said.

I did just think of a way that I would be cofortable using "TYP". A detail veiw of an arrayed set of features, I MIGHT use "TYP" next to the detail name, but most likely I would just put a quantity number.

If it can be misunderstood, don't do it.

 

[11echo]

Yeah Well I started Drafting WAY BEFORE 1982, so I'm afraid I'm stuck with the "TYP." notation! And in my nook of the world, nobody seems to have a problem with either! Just chalk it up to another "old timer" thing! *L* ...Mark

 

[ewh]

A case of "That's the way we've always done it"?

 

[ctopher]

Very common saying. A lot of campanies live by it.
I witnessed once an engineer getting fired for saying it.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[11echo]

You know in retrospect I'm sure there are guys on this forum that have to live and breath the latest/greatest ASME Y14.what ever ...because of the discipline & company they have chosen to work in/with. And my hat is off to them! However there is always a 360 Deg. view of the world, and standing in your shoes and proclaiming your view is the only right way is not correct either! I myself work in a 100 year old oil field and have to deal with all kinds of people, with all kinds of experience, so trying to stay on the cutting road of the latest greatest rules may NOT benefit a project I might be on. So calling out a repetitious fabrication detail as "6 PLC.s TYP." maybe less confusing the "6X" ...Shouldn't that decision be left in the designer/checkers hands, as to what they feel would more easily understood by the people that have to fabricate the details? My $0.02! ...Mark