Question on Surface Roughness Callout 1

[ryandias]

Is there a difference between the call-outs in the image?

 

[KENAT]

I believe the second one may be wrong. The actual surface roughness value goes as shown on the left hand symbol.

Take a look at this link.

http://www.misumiusa.com/CategoryImages/Metric_2006_pdf/METRIC1837-1838.pdf

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[ctopher]

I agree, the first one (left) is correct.

Chris
SolidWorks 10 SP4.0
ctopher's home
SolidWorks Legion

 

[321GO]

Second one is not wrong perse, it is normaly used for (German) Rz value's, something completely different than Ra values, watch out!

Furthermore it can also mean a certain measuring length in mm, it all depends.

 

[KENAT]

3121GO, the reason I said 'may be wrong' is because while a 'number' can go in that location and mean something, it doesn't mean what I took the OP wanted it to mean.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[TED7]

Both are showing the same thing. The right one is correct as per current ISO standards (BS and DIN included) but both are suspect as they do not denote Ra or Rz. In such a case the lettering is normally put before the number using the symbol shown on the right to read "Ra 1.6"

 

[dtmbiz]

FYI,

This may be helpful

Below is a link to a fairly thorough presentation of surface roughness explanation with comparison of ASME to ISO.

http://www.scribd.com/doc/19597179/Surface-Finish-101-Bcmac-Com

 

[nithinku]

Ninja182

No need of mentioning Ra. Just value is Enough.
But for Rz we need to show Rz along with value.

NX 6.0.2.8 MP4
Teamcenter 2007
WINDOWS XP (64 Bit)

 

[TED7]

I work for a firm where most of the components use Ra but some running surfaces require Rz, I think its mainly to keep the drawings looking tidy that our internal standards dictate we lable both.

The other reason im all for it is that it's 2 characters and I'm all for stamping out every trace of ambiguity - have come across far too many people trusted to read drawings who given the chance will misinterpret everything they can get away with.

Will Walters
Sheffield UK
Designer of machine tools - user of modified screws

 

[321GO]

"The other reason im all for it is that it's 2 characters and I'm all for stamping out every trace of ambiguity - have come across far too many people trusted to read drawings who given the chance will misinterpret everything they can get away with."

This is what experience brings, sense! I fully agree.