take a new lawnmower blade... it is usually painted black. Take your
grinder or file and grind the edge so that the paint is filed off
evenly. The new shiney edge should be even and straight exactly at the
same angle of the blade edge.

So on an old used lawnmower blade you will make the new shiney edge even
and straight.

James wrote:

I already have a grinder, and a vise. What I am asking for is the
technique.