I've seen that reference in several publications. I don't remember the acid
type suggested, though.
Respectfully,
Ron Moore

"Koz" wrote in message
...
Skimming though a 1904 metalworking text section on shop hints, I came
across this:

Sharpening files. To sharpen dull and worn out files, lay them in dilute
sulphuric acid, one part acit to two parts of water over night, then rinse
well in clear water, put the acid in an earthenware vessel. (typed exactly
as written, by the way)

I was just wondering if anyone had ever tried this and if it worked or
not. Often at swap meets, there are good brand name files for rock bottom
prices because they have been used improperly by people (or their kids, if
they're anything like mine!). If this actually sharpens files rather than
just eating away the "crust", it opens a source for a lot of unusual older
files that one can't even find any more.

Comments?

Koz