Equivalent for # 4 polishing 4

[micalbrch]

Gentlemen,

Can anybody give me an ISO, EN or DIN surface roughness equivalent for #4 polishing or just the corresponding micron value?

Thanks in advance for your help!

 

[CastMetal]

#4 Polish is done with 180grit (US) ~25 Ra (microinch)

Comprehension is not understanding. Understanding is not wisdom. And it is wisdom that gives us the ability to apply what we know, to our real world situations

 

[CorBlimeyLimey]

Architectural or Dairy?

This Australian article is about the best I've come across.

http://www.assda.asn.au/technical-info/surface-finishes/no-4:-the-workhorse-finish

Standards

Until recently, standards defined No 4 finish in terms of the coarseness of the abrasives used to produce a general purpose finish widely used for restaurant equipment, kitchen equipment, shopfronts and food processing. New editions of the American and European standards define limits of surface roughness achieved.

Finishes produced by use of abrasives may be called ground or polished or abraded or linished. These words describe a process and do not specify the end result.

ASTM A480 defines No 4 finish simply as, “General purpose polished finish, one or both sides”. It also states, “No. 4 - A linearly textured finish that may be produced by either mechanical polishing or rolling. Average surface roughness (Ra) may generally be up to 25 micro-inches (0.64 micrometres). A skilled operator can generally blend this finish.”

 

[micalbrch]

Thank you both for your help! That answers my questions. I knew #4 is the grade for restaurant and kitchen equipment but could not imagine what that means in my (European) world.

My question was related to dairy/food purposes, not architectural.

 

[TVP]

DIN EN 10088-2 Table 6:

Special finishes 1G (hot rolled) or 2G (cold rolled)
Type of process route: Ground
Notes: Grade of grit or surface finish can be specified. Unidirectional texture, not very reflective.

 

[TVP]

I meant to include the following as well:

Special finishes 1J (hot rolled) or 2J (cold rolled)

Type of process route: Brushed or dull polished (one surface only unless otherwise agreed upon at the time of ordering).

Surface finish: Smoother than ground.

Notes: Grade of brush or polishing belt or surface roughness can be specified. Unidirectional texture, not very reflective.

 

[KENAT]

Well I could have sworn this site

http://www.ssina.com/finishes/sheetsamples.html

had info but id didn't pop out at me.

Thing is I'd forgotten where that site was and in the process of looking for it found these.

http://www.clearlakefiltration.com/pdf/surface_finish_chart.pdf

http://www.assda.asn.au/technical-info/surface-finishes/no-4:-the-workhorse-finish

http://www.bssa.org.uk/topics.php?article=190

http://www.bssa.org.uk/topics.php?article=47

Posting guidelines faq731-376

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

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

 

[micalbrch]

Thanks to TVP and KENAT, too! More information than I need for now but I put down some notes from your answers to have them for the future.

 

[CastMetal]

Kenat,

Thanks for pulling up that cross reference chart. I didn't realize #4 finish had such a wide range meanings, all the way up to 60 Ra (microinch).
Proof yet again advice here is only worth what you pay for it.

Comprehension is not understanding. Understanding is not wisdom. And it is wisdom that gives us the ability to apply what we know, to our real world situations