04-17-2018, 02:20 PM
(04-15-2018, 10:57 PM)Bud Wrote: I've been following along on this thread since the beginning Mr. Rick KR so maybe can offer my understanding. The edge rolling test is done like a slicing test in that the bearing rolls up against and then down the edge and tries to push it over. The edge tester then measures how much the edge rolled. It's not like cutting rope in that the test is not designed to tell how much the edge might have been worn away by cutting the rope. Maybe cutting rope is just another way to roll the edge. Maybe rope has abrasive in it and actually grinds metal away, I don't know. I think that if someone wants to know how much their edge has been ground away from cutting something that that would be a different kind of test. If I have this test wrong then someone can correct me. Hope i have it right and this is helpful to you.
Hello Mr. Rick Kr, Welcome to the Forum! It's really great to have you here.
I'm barely a novice machinist, but I have several good friends (and one of my heroes) who are magnificent machinists. I've always been in awe, and have tremendous respect for your trade. I finally acquired a full size digital knee-mill several years ago, and it is my favorite single piece of equipment, spanning three well appointed shops. I appreciate your comments, and can easily recognize your point of view.
Mr. Bud, you are correct that cutting rope is not the same as rolling the edge. They are basically the two ways that edges are affected to a point where they no longer perform as desired. IMHO, one is not necessarily more significant or important than the other.
These two properties of edges have been recognized for a very long time. They are called "edge stability" and "abrasion resistance". Of the two, abrasion resistance is something that people have a better understanding of, because it's always been more practical to quantify edge degradation by cutting stuff.
Most often you'll hear of people testing edges by cutting cardboard, but I don't understand why. Cardboard is un-quantifiable. It varies a lot in thickness, density and composition. It is recognized to be abrasive, but to an unknown degree. It's free. That's it's best attribute.
There is a reason very few people are willing to actually test cutting performance. It is a lot of difficult, tedious work. To the best of my knowledge, and Mr. Mike can correct me if I'm wrong, I've probably been using a BESS machine to Measure edge degradation far longer and far more than anyone else, but I'm a neophyte when it comes to cutting rope.
Many Decades ago, Mr. Ed Fowler, one of the most well recognized bladesmiths in America, and a founding member of the American Bladesmith Society, decided to try cutting rope instead of cardboard. Rest assured, Mr. Ed Fowler has been as serious about quantifying and improving every aspect of blade performance as anyone else I've ever heard of, and he has been whole-heartedly working non-stop on it for nearly 50 years.
When I decided I wanted to make the best knives I possibly could, I pulled out all the stops. I went directly to the most well recognized and respected bladesmiths in the US, and faithfully apprenticed under them. Money was no object, other than I know you generally get about what you pay for, so I spent as much money as it took.
I learned as much as possible very quickly that way, and I learned by far the most from Mr. Ed Fowler. For one thing, I learned not to shy away from hard work. If you truly want to make the highest performance blades, you have to figure out the best way to test them, then you have to have the balls to do the required work to the best of your ability. I've been faithfully testing Abrasion Resistance for many years, so I probably do know something about it.
I was very fortunate to run into Mr. Mike several years ago. I was so totally convinced that the BESS machines were revolutionary that I immediately bought a dozen KN100s. I knew one very big advancement had been made, and I wasn't going to have to cut rope until the blade was dull anymore. I could make 100 cuts instead of 500, and Measure edge retention. Or abrasion resistance... same thing. That was the initial concept, and I haven't changed my stance one iota.
One of the main reasons we use manila rope is that over the Decades, it has proven to be clean enough and consistent enough to give repeatable results. It's actually pretty gentle to the edge. There is absolutely no "grinding down" of the edge. If you happen to be testing a blade that's worth $500 to $2500 (which are almost the only blades we test), it's very significant that rope doesn't mar the sides of these blades like cardboard.
Another item of prime importance you mention is the question of whether rope "...is just another way to roll the edge". Well, it's never rolled a properly heat treated HEPK 52100 blade in 50 years. When some of us on this forum were testing the Work Sharp M3 edge denting device, I cut a Bunch of rope with many different knives. No Rolled Edges. Period.
Obviously edges do roll. I've seen rolled edges on soft stainless steel from cutting cardboard. Every edge will roll every time it hits something relatively hard. No edge survives cutting on a ceramic plate or granite counter top.
The SET edge rolling machine produces edge stability failure every time. It's the first machine of it's kind, but it is newer than new, and frankly, nobody knows exactly what this will lead to. I'm sure it will lead to some very interesting, conclusive findings. I know I'm excited to see what I can discover.