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  for Metal Finishing since 1989
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How is a mirror finish to be called out

2007

Hi,
We are a small machine shop that is doing work for a Aerospace company which also does marine work too. A couple of the parts that we make require what started out to be a (1.6p) finish and know they want to change to a mirror finish. We can buff the part to get the finish they want but they do not know how to specify it or call it out on they print. Is there a spec out there they we can go to that tells what a mirror finish really is. We would like to be able to send these jobs out for requote but be able to make sure that everybody uses the same spec to acquire a mirror finish.

Thank you,

Pete Basile
Foreman - Loves Park, Illinois

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Microinches or micrometers RMS are an easily verifiable measurement for roughness if the part can be sensed by a profilometer (works with a reciprocating sensing tip similar to an old phonograph needle). The surface has to be flat and small enough to fit on a tabletop or big enough to accept the mounting of the apparatus over it. Otherwise a visual and tactile surface finish comparator will be your best reference. They come in several readings used by different industries.

Guillermo Marrufo
Monterrey, NL, Mexico
2007