Specifying a surface finish to a region of a face

[16valan]

Hi,

We have a cylindrical part, a tube I want to bore out to 295 I.D x 845 Long.
On one end I want to specify a surface finish to a region of the I.D, say up to 50mm in, as this is going to be a sealing face.
The surface finish of the remainder of the bore is not important, so long as it's of an appropriate quality to maintain the dimensional constraints (which are forgiving).

So my question is, what would be a legitimate way of conveying this on an engineering drawing?

Thanks in advance.

 

[CheckerHater]

What standard are you working to?

In ASME world you can use dots with letters to create “from – to” requirement in the way similar to specifying Profile tolerance A<----->B.
Also you can separate areas with different surface requirement with the thin line accompanied with dimension; then reference it like “Ra 63 .50 width” or something like that.
Another option is to associate surface texture with the dimension, as: “.247/.249 thru, .2500/.2505 .50 deep Ra 16

ISO recommends using chain line with dimension to designate area that requires special treatment. ASME uses chain line for same purpose, so it will be understood, even if it’s not in the book.

 

[16valan]

Thanks CheckerHater.
We're working to ISO. I think the chain line, dimension, and a surface symbol attached to the dimension is the way to go. That would be clear to me if I were reading the drawing..
Thanks again, Alan

 

[ctopher]

You can make a section view of the part, then dimension the surface 'roughness' depth with the callout.

Chris
SolidWorks 11
ctopher's home
SolidWorks Legion

 

[MechNorth]

The "between" application isn't recognized in the surface finish standard, but may be understood anyway, though it will take more written text to define everything. A detail of a cross-section would be the best way to go, incorporating an offset chainline showing the extent of the application (supported in Y14.5, 4.5.10, and Figs. 4-23 & 6-47).

Jim Sykes, P.Eng, GDTP-S
Profile Services

http://www.profileservices.ca

TecEase, Inc.

http://www.tec-ease.com