are these surface finish symbols an old industry standard?

[Tmoose]

I've seen this type of "f" symbol on drawings from at least 2 companies dating back to the 50s or even before.

Were they part of an actual "standard" once upon a time?

 

[ornerynorsk]

These were widely used in my earlier days, I don't see them so much any longer. I was taught to understand those marks as "requiring machine finish", not mill finish, as-cast, or what have you.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[Tmoose]

Here is a screenshot of our "standard" that allegedly provides a translator to the modern era.