The authoritative public forum
  for Metal Finishing since 1989
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Surface Finish Specifications

 

I have a small stainless steel part ( about 1 inch diameter) which needs to be polished to a mirror finish. I see from reading here that stainless is not an ideal reflective material. We have concluded that the type of finish one might find on a stainless camping mirror, or such, would be good enough. Basically if I can see my face in it, it will work for our purpose.

The problem is that I have no clue as to how to specify this type of finish to the company who will make the part.

Thank you for any help you can provide me in this matter.

Rudy Chapski
- Dayton, Ohio

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The finish you are referring to is ASTM No. 8 or non-directional mirror finish on stainless steel. This typically is easily done on flat sheet products, however harder on round parts. #800 grit is probably the best that can be done on tubular products with very slight angel hair grains.

Michael Liu Taylor
specialty stainless steel distributor - Dallas, Texas
 

Get the company to produce a range of finishes and then choose & agree & sign-off on max/min/nominal standards. One master set for you and one for them.

John Tuohy
- Ireland

Depending on type of Stainless Steel, I would look in to electropolishing your part. This will give you the mirror finish that I believe you are looking for.

Chris Snyder
plater - Charlotte, North Carolina

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Thank you all for your quick and very helpful replies. with this info I will proceed with our project.

Thanks again,

Rudy Chapski
- Dayton, Ohio

For the best stainless mirror you need to specify a ferric stainless steel. AISI 434 is what I would suggest. This has the best mirror quality in the as-bright annealed condition. Subsequent buffing would guarantee mirror quality.

Dr. Michael McGuire
- Pittsburgh, Pennsylvania, USA

about the mirror finish, what would the spec. be on a small alum. part

John Caporizzo
- Norwood, Massachusetts
December 2, 2008