Old Drafting Symbol for Surface Finish (circa 1978)
Old Drafting Symbol for Surface Finish (circa 1978)
(OP)
I'm reworking an old drawing from 1978 to update some features. There's a symbol on it for surface finishing that I can't find an exact definition for anywhere. The most I've found is that it's the old surface finish/machining symbol, but the source doesn't indicate if what I have is a generic symbol or if there are specifics indicated that I need to transfer to the new symbol. I've attached a screen shot of the old symbol, it looks something like an integral with a slash through it. Anyone know specifically what this is, as in what's it called and does it indicate anything beyond the need for surface machining (i.e. grain direction, roughness, etc.)? Thanks.





RE: Old Drafting Symbol for Surface Finish (circa 1978)
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Old Drafting Symbol for Surface Finish (circa 1978)
RE: Old Drafting Symbol for Surface Finish (circa 1978)
Also, if accompanied by a note, it takes on more or less additional meaning, like on enclosed picture.
Unfortunately, if your drawing doesn't have a note, the symbol doesn't have a lot of meaning as well
"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future
RE: Old Drafting Symbol for Surface Finish (circa 1978)
RE: Old Drafting Symbol for Surface Finish (circa 1978)
Abbreviation or symbol: ƒ
Definition: finish
Description: An italic f (Latin small letter f) written on a line representing a surface was an old way of indicating that the surface was to be machined rather than left in the as-cast or as-forged state. The "f" came from "finish" in the sense of "machine finish" as opposed to raw stock/casting/forging. Later the ASA convened upon a letter V (specifically a sans-serif V) touching the surface. Soon this evolved into the "check mark" sign with accompanying number that tells the reader a max roughness value (RMS, microinches or micrometres) for the machined finish, to be measured with a profilometer.