Where the
world gathers for metal finishing
Q&As since 1989


-----

Surface Roughness Question

I have a customer drawing that has a surface roughness symbol on the drawing that I have not seen before. It has a surface finish of 50 and a then there are two numbers under the horizontal line. The first number is 0.030" (This is the roughness sample length) and then the second number(this is my question) of 0.002 (is this a tolerance?). The two numbers are separated by a comma.

Thanks, Tom 50 ___________ \/ .030, .002 Tom Fitzpatrick
- Trenton, New Jersey
2002

You are probably right about the roughness sample length figure. Regarding the 0.002 figure, it could be an incorrect conversion into micrometers of 50 (because it actually translates to 0.0012 mm that is 1.2 micrometer). You can find a good description of thes roughness symbols (the V etc.) in ASME Y14.36.

Giovanni M. Ciriani
- Altavilla, VI, Italy
2002