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Dowel pins and threaded inserts called out on detail drawings 2

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LONDONDERRY

LONDONDERRY

Mechanical
Dec 20, 2005
124
Greeting-
So I'm having this heated debate with a fellow engineer on the following issue.



In a cases where dowel pins, threaded inserts or other parts are permanently attached I call them out on a detail drawing (except a weldment). For example, a sheet metal drawing that has PEMS (threaded inserts) pressed in can be called out on a detail drawing instead of creating another layer of documentation the same for a block with a pin pressed in. I've ben doing this way for 25 years without an issues.
However this engineer tells me thats wrong, and a assembly drawing need to be created that calls out the machined part and the pin. I find it unnecessary to create this extra lay of documentation.
So the question is who's right and who's wrong and is there a drafting standard for this? Maybe this is an issue where its neither right or wrong and its a preference on how to create documentaton. Isn't this type of drawing called and inseperable assembly drawing?

Frank
 
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Inseparable assembly is the term, Y14.24 is the applicable standard section 4.2 specifically.

On ours (per std as I understand it) we set it up like an assy drawing in that it has a parts list, but the dimensions of the finished part where required for manufacture are given on the drawing. Dimensions of 'off the shelf' parts are only given as reference as required - otherwise they're covered by their description in the parts list.

However, it's only one option - the other way as a more classical assy drawing with component part drawings is also correct, inseparable assy drawing just reduces the paperwork potentially.

Posting guidelines faq731-376 (probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​
 
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Yes, everything welded, riveted, pressed, glued, etc. constitutes “inseparable assembly” per ANSI/ASME Y14.24M-1989(R1996) “Types and Applications of Engineering Drawings”

If you are under contractual obligation to comply with Y14.24 or the entire ASME Y14.100 package, then you have no other choice, but create one.

If there is no strict regulation, and your drawings are clear and concise, you can probably get away with cutting some corners, which you probably did for last several years.

Now, when it comes to IA Drawing, I am not 100% sure that standard explicitly forbids you from providing all the necessary information right on the assembly drawing, thus avoiding creating extra detail sheet.

I will be following this thread with interest.
 
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Y 14.24 explicitly allows detailing of the parts on the inseparable assy drawing.

(Y14.24 also allows for multi detail drawings though discourages their use as I recall. Inseparable assy's can be a bit of a hybrid where more than one custom part is permanently assembled together to create the end part.)

Posting guidelines faq731-376 (probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​
 
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From NASA Engineering Drawing Standards Manual (that likely mirrors Y14.24)

An inseparable assembly drawing delineates items (pieces) which are separately
fabricated and are permanently joined together (e.g., welded, brazed, riveted,
nailed, bonded, etc.) to form an integral unit (part) not capable of being readily
disassembled. An inseparable assembly drawing may be prepared in lieu of
individual monodetail drawings for inseparable assemblies intended to be
procured and replaced as a unit, where (except for standard hardware) the
separate parts are of similar or compatible materials. See Figure 20 (all data,
such as notes and list of material, are not shown).

An inseparable assembly drawing shall fully define the end product or detail
assembly as assembled. Pieces of the inseparable assembly may be detailed either
on separate detail drawings or on the inseparable assembly drawing itself. In the
case of weldments, the parts shall not be individually detailed on separate
drawings (due to the consumable material allowances that would have to be shown
on detail drawings), except in cases where extensive machining might be
necessary.
Click to expand...
 
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Thanks, I thought drawings ran this way. I've been drafting since the late 80's and I can't stand when someone says "you're doing that wrong". Usually I interprut this as I want it done my way and they don't understand drafting standards.
 
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