Japanese surface texture interpretation? 2

[Ceramicguy]

I have a Japanese drawing (I think) with a surface texture callout I don't understand. The symbol looks like a standard surface texture symbol allowing for material removal but has a alphanumeric code above the closed triangle of either 3S or 18S. Any ideas on a conversion to an Ra, Rz, Rt or similar? See the attachment for clarification of my description.

Bruce

http://accuratus.com

 

[TVP]

That is an old designation system from previous versions of JIS B 0601. It is indicating Rmax in micrometers.

 

[Ceramicguy]

Outstanding!

Thank you TVP

Bruce

http://accuratus.com