In article .com,
"Bugs" wrote:

Rust resistance and edgeholding ability are contradictory terms.
Stainless steels will not keep a sharp edge. High carbon steel can be
hardened very hard and hold a razor edge, but is very susceptible to
rust. My personal favorite all-round tool steel is car or truck leaf
springs. They are dirt cheap at salvage yards and you can make almost
any tool with it.
Bugs

FWIW, check at automotive spring shops too. One local to me gives away
5160 and 9260 end cutoff drops. Both make very nice and sturdy tools as
you noted.

The one here has given a friend and me pieces up to 4 feet long in
several thicknesses and shapes.