Vassili, I bow down to your greatness. When I say the hair severs into two pieces I am barely touching it to the hair, in a slow, deliberate movement to start whittling it. I'm not samarai swinging at the hair, just slowly touching the edge to it. At a point before that sharpness it is easier to peel lots of fine curls. As for impact testing, have you ever hit a packing staple? Something else unexpectedly hard that is hidden in what you are cutting? M4 edges hold up better than ZDP edges do to that, at least in my experience, in the form of a much smaller chip. It isn't that ZDP just crumbles, it certainly doesn't, but the extent of damage from a packing staple on the edge is much less. I am speaking of some thin knives here that this has happened to me with, edges in the .005"-.007" range with angles on the backbevel well under 10 degrees per side and a 10-15 per side microbevel. The edges will also deal with lateral loading better, which often is unavoidable in real world cutting, though not much of an issue just cutting in a jig for cutting rope.
I know how much work you did on your testing, and I really applaud your efforts, but do you really think it is the last and only word on edge retention or knife performance? It certainly is a huge amount of work and admirable, but I also put a lot of stock in Phil Wilson's testing and experience, and also the testing of lots of others. In my personal testing I used 5/8" manilla rope to compare D2 to CPM D2 and it was a pain to do multiple runs with lots of stopping to try to measure sharpness. I have since just gone by using the knives for EDC or other tasks to compare them and see how they hold up over several sharpenings and at different geometries. A lot of times I will cut a defined amount of cardboard to directly compare a couple knives, but not that often any more. Recovering from back surgery sucks. I think limiting yourself to 15 degrees per side is really limiting your performance with some of the better steels like ZDP 189 and M4, which take thinner, more acute edges with ease and keep on cutting. Another thing that would be interesting is for you to take a knife like my SE Endura 4 Wave with a Tom Krein FFG and see how much the SE improves the performance of the VG-10 steel. It came to me hair whittling sharp, gets back that way on the sharpmaker, and holds it's edge much longer than PE VG-10 in my experience. I would also like to see you compare a Tom Krein sharpened edge for slicing rope. It would be interesting to see how a tree topping 120 grit edge fares in your testing, as his edges last a very long time in sling up cardboard and rope for me. Obviously using a longer slice, which is what most people use for rope, skinning, ect., will let coarser finishes shine more than a push cut test. Phil Wilson uses very coarse edges as well, from his years of experience doing work like skinning they are the best for that and his rope slicing tests. I personally have had polished edges last a really long time doing the same work, but a well formed coarse edge that tree tops hair would be interesting to do an extended slicing test on. Again, I always go back to my polished edges, but Tom Krein's 120 grit edges are very impressive.
I'll now defer to you on all things knife related and exit this discussion.
Mike
. Even though Phil makes identical test knives from different steels and sharpens them the same to make more fair tests and Vasili uses wildly different knives sharpened quite differently to compare the steels, still he feels he's methods are ze absolute, last and only objective words.
