Surface Roughness Callouts - Definition of a Surface 4

[tornadochaser]

When identifying a surface on an engineering drawing, are all tangentially-connected surfaces considered part of that surface? Or do I need to identify all the tangentially-connected surfaces separately (for example: point to surface A, surface B, and a fillet that connects them)?

Per ASME Y14.36M-1996:
"When the symbol is used, it affects the entire surface
defined by dimensioning. Areas of trans i~ion, such as
chamfers and fillets, shall confom with the roughest
adjacent finished area unless otherwise indicated."

My interpretation of this is that I would need to identify two surfaces that a fillet may connect but would not have to have a leader pointing to the fillet itself. Would this extend to general identification of surfaces (i.e. if I had a note for masking surfaces during painting, would I need to identify surface A, surface B, and not the fillet? Or all 3? Or just 1 of the 3 and the other two would be implied due to the tangency)?

Thanks for the help.

Matt

 

[mfgenggear]

Matt

one way to cover it is this way,

Unless Otherwise Specified
all surfaces 125 micro or better ( or the needed micro req'd)( using the standard micro surface symbol)

Then for those special areas specify the exact surface micro required.
32 micro surface -A- ( using the standard micro surface symbol)
if the adjacent radii requires a different surface micro than the standard
then it would need a separate specified micro.

then for the painted surface a note could be written as such
all surface micro finish apply before painting or coating.

HTH

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

 

[tbuelna]

tornadochaser-

Think about in these terms: It will only require a few minutes of your time to add detailed dimensions, notes, callouts, etc. to your engineering drawing explicitly defining the surface roughness you will accept on the parts procured based on your engineering drawing. But the cost of a single part rejected based on failure to meet an excessive surface roughness requirement can be many times that amount. Not to mention the bad feelings it will create between you and your vendor.

Unless you are very specific in what you require, you cannot complain about what you get.

 

[KENAT]

tornadochaser, your interpretation for surface finish on the fillet is about right - so long as you're ok with the rougher of the two finishes.

However, for things not explicitly covered by the standard, you'll need to be clear with your annotation. Now this may form part of a note, not necessarily require dozens of leaders to every relevant fillet.

forum1103 can be a better place for this type of question.

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(probably not aimed specifically at you)
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[tornadochaser]

Thanks for the info guys. My question is more on other places where you'd indicate surfaces besides for surface finish callouts... E.g. if I had a flag note like the following:

"3. PAINT INDICATED SURFACES PER..."

and I had a flag pointing to a surface with other surfaces connected tangentially what would be the expected outcome... would the painted mask off all the other surfaces?
or would the painter mask off all non-tangentially-connected surfaces?

I'm surprised ASME Y14.100 or Y14.5 (or another standard that they reference) wouldn't have an explicit definition of the term "surface"... and extending to all tangentially-connected surfaces seems the most straight-forward way to define it.

Unless someone has a better way the easiest thing seems to be :

"3. PAINT INDICATED SURFACE AND ALL TANGENTIALLY CONNECTED SURFACES PER..." or something like that

 

[KENAT]

Unfortunately for some applications of the word 'surface' defining it to mean any tangential chain of 'surfaces' would be problematic. E.g. surface profile GD&T control.

Sometimes you can say 'paint all external surfaces' and then indicate somewhere what's inside and what's outside - or similar situation.

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[mfgenggear]

if painting the adjacent surfaces has no effect to the functioning of the part.

I would do like this
painted surfaces, adjacent areas optional.

HTH

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

 

[mfgenggear]

I believe some time it's OK to bend the rules in order to clarify a drawing, or write an exception to the rule.

Just my thoughts.

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

 

[dgallup]

I would indicate the zone with the requirement with an offset chain line .

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[KENAT]

Good one dgallup, OP could also use A<-->B type annotation as well. Indicate points A & B and use the 'between' symbol.

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[tornadochaser]

thanks everyone... it seems there's a few options to chose from but what it really comes down to is that I need to be more explicit in identifying the surfaces and there isn't any explicit assumption of a tangential chain of surfaces.

Great suggestions dgallup and KENAT.

 

[tornadochaser]

If anyone else is curious about this topic they talk about using offset lines for area indication is ASME y14.5-2009 section 1.7.3

Looks like offset chain lines are the way to go for me...