which steel gets sharpest

[johnlucas]

PM 11 is a metal from Crucible steel I believe.  It means it is powdered metal an has 10% Vanadium in the steel.  If you not familiar with particle metal or powdered metal it is sort of roughly a mixture of metal particles in  sort of a powder format.  You can mix much more of other materials than you can with molten steel.   PM V15 for example is 15% Vanadium.  You can only get 4% in melted steel.   The Vanadium adds toughness which makes an edge hold up longer.  Veritas is using V11 in some of their plane blades.  The reason a lot of tool companies aren't using V15 is simply cost.  It is about 4 times the cost of V11.  It does increase edge holding about 2 to 4 times over V11.   I have a skew that is V15. Doug Thompson of Thompson tools tried to sell some tools made out of V15 but they were simply too expensive so he quit.  fortunately I got one of them.   
       Can't tell you much about how grain size affects edge quality other than with carbides.   The new carbide cutting tools have smaller carbide particles.  what they are calling Nano carbide but that's just salesman talk for smaller.  The smaller particles let you get an edge that is vastly superior to older carbide cutting tools.   The old router bits, Saw blades and metal cutting tools simply would not get very sharp at all.    The Hunter tool that I tested in my article was amazingly sharp straight out of the box, which is good because i tried everything to sharpen one of those cutters and nothing worked.  Everything I tried simply chipped the edge.