Home made chisel

I amongst John Webb's tools, I found this unprepossessing tool - a home made chisel.

I've no idea what John made it from, suggestions are welcomed, but it's brilliant for removing excess solder from the surface of brass kits. I'm guessing that's what he made it for anyway.

While I have a 3-sided scraper which is good, but I still find it hard not to gouge the surface of the brass with a hard steel blade. This seems softer (it's still steel) and easier to slide along the metal.

Maybe if I owned a grinding wheel, I'd make more of these sorts of things myself, old books always mention grinding old files to make chisels and I've certainly read scratchbuilders who have manufactured their own tools.