stock material roughness override...

[Tenkan]

forgive me in advance on what is probably a basic drafting question. We have a roughness callout in our title block tolerances, but I want to call out a stock material and not have the surface roughness tolerance apply. i.e: I dont want them to do anything with the surface of the stock material except a finish callout later... its not critical.

does simply indicating the material as stock override all the title block tolerances specifically the general roughness? Or is it implied to only override the stock material dimensional tolerances?

lightweight, cheap, strong... pick 2

 

[CheckerHater]

There is nothing “basic” about your question (or any other question for that matter).
Several companies resort to “creative drafting” techniques, mixing written rules with made-up ones.
Generally, surface finish symbol applies to machined faces, which brings another question: on your drawings, is it possible to clearly distinguish between machined and raw surfaces?
Either way, don’t be afraid of creating a note to clarify your intent.

 

[drawoh]

Koda94,

How about adding a view showing a typical section, and apply a surface finish specification that the stock material meets easily?

--
JHG

 

[pmarc]

How about placing "the circle in the vee" symbol indicating that material removal is prohibited for the stock material?

 

[dgallup]

Can you not edit the value of the surface roughness in the title block? Our title blocks bring in the parameter values of the drawing model. So the default roughness is the appropriate value for that model, not some arbitrary value that some wingnut thought would apply to every part ever made.

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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.

 

[Tenkan]

Checkerhater, I think your reply answers my question as the machined faces are distinguishable, in my case the stock material will be cut to length. After the part is cut we will apply a finish to the whole part… it will be important that the cut faces meet our roughness tolerance but its not part of the contract to dress the OEM surfaces before applying finish.

All are good suggestions, the roughness value in the title block is linked to a smart property so it can be edited to accommodate a stock callout but I don’t know how to find the roughness value of the tube. I think in this case I can add a note stating ‘roughness applies to machined faces only before finish is applied’


lightweight, cheap, strong... pick 2

 

[CheckerHater]

You don’t have to know the roughness of the tube, because you are not the one making the tube.
To designate the surface left in the state from previous manufacturing process use "the circle in the vee" suggested by pmarc.
If you cannot place “no machining” symbol into your title block, leave title block value for machining and create note like “SURFACES IDENTIFIED AS “STOCK” (the circle in the vee)”
You can also attach “machining prohibited” symbol to your “stock” dimension as well.
It is hard to be precise without knowing how exactly your part and your title block look like, but I hope you were given enough ideas for today

 

[CheckerHater]

Koda,
You mentioned "finish"
Are we talking paint or something like zink-plating?

 

[Tenkan]

Checkerhater, more good suggestions again thank you, some of those will work as well. I added a note to the drawing

The part gets polished. Aside from that my company has incredibly strict confidentiality agreements and I’m not comfortable describing the actual part, material and specific processes. I think I could get away with explaining why I’m on a web forum asking drafting callout questions, but not describing the parts I work on.


lightweight, cheap, strong... pick 2

 

[CheckerHater]

Well, polishing counts as “material removal”.
Now I am genuinely confused: why do you care to specify raw material surface if the part is machined anyway?

 

[Tenkan]

yes, polishing removes material. The requirement is the polishing to be done on the supplied surface as is. Since our title block includes a general roughness value I wanted to make certain that it is not applied to the provided material or the finishing process.

lightweight, cheap, strong... pick 2