Surface Finish, Old Symbol

[TangoCleveland]

We have a 1940's vintage drawing of a special bolt that calls for a surface finish with an old symbol; it looks like an integral sign and has a number after it - our symbol is f 4. I have a 1939 Machinery's Handbook that says f 1 is rough machined, f 2 is ordinary machining, up through f 5 for polished. f 4 is a ground surface, which makes sense for this bolt. Our client has another undocumented reference that has the numbers in reverse order, f 5 is rough and f 1 is polished. Can anyone shed some light on this finish symbol?

 

[jlhmaint]

larry, check this site might help not sure.

http://www.predev.com/smg/specification.htm

 

[Woody1]

I checked all my old stuff including a asme reference and f4 is a ground surface corresponding to the common 32 finish of today. Woody Ebersold
Consulting Engineer
"AN EXPERT IS ALWAYS SOMEONE FROM OUT OF TOWN"