-- The Home Page of the Finishing Industry
23+ years of serious education, promoting Aloha,
& the most fun you can have in metal finishing smiley
    no popups, no spam
on this site
current topics
topic 7313

Stainless Steel Brush Finish Specifications


What constitutes a No. 4 brush finish on stainless steel? What is the min/max roughness for a No. 4 finish? Where can I find more info on No.3, No.4, No.6, and No. 8 finish specs?

Joseph Litza
- Chicago, Illinois


No. 4 finish is typical 150-180 grit (satin) finish. Much like the stainless steel shutter found on 3.5" floppy diskette. No. 3 finish varies with the mill/polishers can be as low as 60 and as high as 140 grit. Roughness average (Ra) value is very dependent on the mills/polishers. The flatness of the coils/sheets, as they are handled and produced from the mills is a major decisive factors in the final Ra value.

No. 8 finish is a true mirror finish. No residual polishing lines should be found on the surface of the stainless. Roughness average (Ra) is 1 microinch or below.

I believe the Specialty Steel Industry of North America has free handbooks on the finishes of stainless steel sheets.

Also, ASTM should have finish specifications as well for a fee.


Michael Liu Taylor
Michael Liu Taylor
   specialty stainless steel distributor
Dallas, Texas



I have a part print that requires a #3 brush finish. Material is 380 Al. The only surface finish standard I have is an Ra reference. I do have a profilometer, but not sure what Ra or Rz value will roughly equal a #3 brush finish. Any help would be greatly appreciated.


Shane Lindley
- Clearwater, Florida

September 15, 2008

I have a component machined with aluminium material. I have to callout in drawing its surface finish symbol. Can any one help me in this issue.

Kumar Pavan
- New York, USA

August 2, 2011 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

What is the conversion of brushed #2 stainless steel surface finish equivalent?

Matthew DuVall
Quality Specialist - Bloomington, Minnesota

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Comment to THIS thread START a NEW threadView CURRENT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2018, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.