Diamond plates/wheels. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> We already have knives that are too hard to sharpen with stones, in the form of ceramics. It's just that they're not tough.

Intentional abuse of a Busse family knife, to me, is pretty much limited to things like shooting it, or attacking rocks. A knife is not a masonry chisel, or ballistic armor. Other things that are kind of "emergency use only" are chopping through sheet metal, or batoning with a rock or hammer. The knife will survive at least for a while; but NO steel will stand up to that indefinitely. Jobs like splitting wood and digging and prying on stuff, which are fairly abusive of a lot of knives, are what the Busse family aims at. You don't make a quarter inch thick, spring tempered slab unless you plan on people doing extreme things. It's not a pocket knife, it's not a razor.