01-07-2018, 08:50 AM
I've been wondering for ages why this couldn't more easily be a one step test, as in an edge denter, somewhat like a simple Rockwell device. After all, I truly believe the subject at hand is specifically measuring edge hardness now. Edge rolling is a different subject altogether IMHO. Maybe I don't understand what you're trying to do.
Trying to accurately roll an edge might be very difficult, and subject to the differences in type of steel. There is a term for a particular steel's predisposition to roll, called "edge stability". It's not a new term, I've heard it thousands of times, so I assume someone has done some homework on it. I think it's a known characteristic of different types of steel, Besides edge geometry.
If I were trying to accurately roll an edge, I wouldn't have the edge 90° to the hard surface, because the chances of rolling one way, then arbitrarily flatten and roll the other way would lead to imprecise results. Of course the test device would have to be more substantial, to mitigate torque, but I don't know exactly how else you could roll an edge precisely and consistently. I'm also unsure what affect a precisely rolled rolled edge would have.
On the other hand, you have another, more popular way to degrade edges. Cut Stuff. I've cut enough rope to have a pretty good understanding of the accumulative affect of normal wear. This takes nothing more complicated than simply getting used to cutting rope. I know it may seem like an oversimplification, and a lot of effort, but I know it works.
I hate to think of how much time and effort I've wasted cutting rope until the knife gets dull, compared to how simple it is to make a hundred cuts and measure the change in BESS units. That's Truly what I thought Edge Retention Testing would consist of. Just rope and a BESS machine. Edge retention probably has much less to do with rolled edges than simple wear, as long as you aren't cutting on glass or dishes or whatever stupid people cut on.
I've actually done a fair amount of testing using this method, and I've been waiting for about 9 months for someone else to practice this simple procedure.
I must say, I don't have the foggiest idea about flash temperatures of thousands of degrees F for .000001 second. That's completely beyond my sense of reason, or the reason of anyone I know who has sharpened thousands of blades. For every page written about flash temperatures such as this, we have a decade of whole world, real life experience.
Please consider this. I'm not talking about extraordinarily limited, Laboratory Induced Micro-Theory here. Facts. Probably Trillions of sharpened knives. As I understand, this Theory is not limited to power sharpening, so we are in range of every single sharpened edge the world has ever seen.
I'm sorry, but I'm going to go with what has been positively known for centuries, not someone's pet lab theory. Seriously, how much information are we basing all this hubbub on?
There is a very simple rule by which we've all been playing for hundreds of years. I don't understand why we need to reinvent the wheel. If the edge doesn't change color, everything's groovy. It's worked so well, no one has been able to figure out something more accurate to date. No One. Ever.
If you want to know if you're affecting the hardness of an edge, feel the blade with your fingers. If it burns your skin, it may be 300°F, and you need to dunk it in water and do something differently. Like simply not using as much pressure, or traveling faster, or changing belts. I positively guarantee 300°F for a few seconds is absolutely meaningless. I state that as a matter of fact that has stood for centuries.
Here's one last way to prove beyond the shadow of doubt that this manner of softening steel is ridiculous. Cumulative affect. Sharpen one blade a hundred times and see if you can tell the difference. You certainly wouldn't be the first to sharpen one knife a hundred times, and I simply have nothing to show it's ever made any difference at all.
Or I could be wrong. Like everyone else.
Trying to accurately roll an edge might be very difficult, and subject to the differences in type of steel. There is a term for a particular steel's predisposition to roll, called "edge stability". It's not a new term, I've heard it thousands of times, so I assume someone has done some homework on it. I think it's a known characteristic of different types of steel, Besides edge geometry.
If I were trying to accurately roll an edge, I wouldn't have the edge 90° to the hard surface, because the chances of rolling one way, then arbitrarily flatten and roll the other way would lead to imprecise results. Of course the test device would have to be more substantial, to mitigate torque, but I don't know exactly how else you could roll an edge precisely and consistently. I'm also unsure what affect a precisely rolled rolled edge would have.
On the other hand, you have another, more popular way to degrade edges. Cut Stuff. I've cut enough rope to have a pretty good understanding of the accumulative affect of normal wear. This takes nothing more complicated than simply getting used to cutting rope. I know it may seem like an oversimplification, and a lot of effort, but I know it works.
I hate to think of how much time and effort I've wasted cutting rope until the knife gets dull, compared to how simple it is to make a hundred cuts and measure the change in BESS units. That's Truly what I thought Edge Retention Testing would consist of. Just rope and a BESS machine. Edge retention probably has much less to do with rolled edges than simple wear, as long as you aren't cutting on glass or dishes or whatever stupid people cut on.
I've actually done a fair amount of testing using this method, and I've been waiting for about 9 months for someone else to practice this simple procedure.
I must say, I don't have the foggiest idea about flash temperatures of thousands of degrees F for .000001 second. That's completely beyond my sense of reason, or the reason of anyone I know who has sharpened thousands of blades. For every page written about flash temperatures such as this, we have a decade of whole world, real life experience.
Please consider this. I'm not talking about extraordinarily limited, Laboratory Induced Micro-Theory here. Facts. Probably Trillions of sharpened knives. As I understand, this Theory is not limited to power sharpening, so we are in range of every single sharpened edge the world has ever seen.
I'm sorry, but I'm going to go with what has been positively known for centuries, not someone's pet lab theory. Seriously, how much information are we basing all this hubbub on?
There is a very simple rule by which we've all been playing for hundreds of years. I don't understand why we need to reinvent the wheel. If the edge doesn't change color, everything's groovy. It's worked so well, no one has been able to figure out something more accurate to date. No One. Ever.
If you want to know if you're affecting the hardness of an edge, feel the blade with your fingers. If it burns your skin, it may be 300°F, and you need to dunk it in water and do something differently. Like simply not using as much pressure, or traveling faster, or changing belts. I positively guarantee 300°F for a few seconds is absolutely meaningless. I state that as a matter of fact that has stood for centuries.
Here's one last way to prove beyond the shadow of doubt that this manner of softening steel is ridiculous. Cumulative affect. Sharpen one blade a hundred times and see if you can tell the difference. You certainly wouldn't be the first to sharpen one knife a hundred times, and I simply have nothing to show it's ever made any difference at all.
Or I could be wrong. Like everyone else.