I have noticed that more acute bevels like 15 dps seem to come out sharper than less acute bevels like 20 dps. (I'm typing on a laptop and can't figure out how to make a degree symbol). Since I don't chase super sharp and anything 150 or less if fine with me for kitchen knives, I never really checked it out but I have noticed it.
I've even pondered it occasionally and it always seemed like both 15 and 20 degrees come to the pretty acute edge and it seemed like both should be able to be equally sharp. Nonetheless, it has sort festered in the back of my mind as a curiosity I never really figured out.
The EOU post quotes a source stating, "Edge width is controlled by bevel angle and only bevel angle", as though bevel angle is the limiting factor of how sharp an edge can be.
The subject of the KG post is, "Why the 40° edge will not score as well as the 20°", and here it seems that "score" is key referring to BESS testing insofar as the edge must actually penetrate the test media to some depth thereby bringing the bevel angle into play as explained in the post. That is not saying that the apex is not as sharp, but that it does not test as sharp due to how test media severs.
I have always had this nagging suspicion that more acute bevels can be made sharper than more obtuse bevels but except in extreme examples I don't understand it because at the very apex an edge is formed. It is only when a surface is penetrated that bevel angle becomes significant as it interacts with the material being cleaved.
As I understand it, the whole keen/sharp thing attempts to conflate edge apex width and bevel angle as a unified definition of "sharpness". In my mind they are separate entities. Edge apex width is sharpness, and bevel angle is, well, bevel angel. Together they dictate how a blade will perform in a cutting operation.
All this is actually pretty ambiguous because none of our edges come to a perfect edge. The edge has width and rounding so it begs question of where it's measured; 1 micron back from the edge, 2 microns, 3 mm, etc. It's all so vague that when the minutia is considered it's almost impossible to nail down and since there is no standard I just don't go there.
So I have some questions: If we had the equipment to do it, could both a 15 dps edge and a 20 dps edge be 1 atom or molecule or whatever the smallest steel particle is wide? Is bevel angle a limiting factor in apex width or is this a limit of our ability to test it because bevel angle effects the test?
Of course for all intents and practical purposes this is academic and I doubt I'd notice when slicing an onion, but it is interesting nonetheless.
I've even pondered it occasionally and it always seemed like both 15 and 20 degrees come to the pretty acute edge and it seemed like both should be able to be equally sharp. Nonetheless, it has sort festered in the back of my mind as a curiosity I never really figured out.
The EOU post quotes a source stating, "Edge width is controlled by bevel angle and only bevel angle", as though bevel angle is the limiting factor of how sharp an edge can be.
The subject of the KG post is, "Why the 40° edge will not score as well as the 20°", and here it seems that "score" is key referring to BESS testing insofar as the edge must actually penetrate the test media to some depth thereby bringing the bevel angle into play as explained in the post. That is not saying that the apex is not as sharp, but that it does not test as sharp due to how test media severs.
I have always had this nagging suspicion that more acute bevels can be made sharper than more obtuse bevels but except in extreme examples I don't understand it because at the very apex an edge is formed. It is only when a surface is penetrated that bevel angle becomes significant as it interacts with the material being cleaved.
As I understand it, the whole keen/sharp thing attempts to conflate edge apex width and bevel angle as a unified definition of "sharpness". In my mind they are separate entities. Edge apex width is sharpness, and bevel angle is, well, bevel angel. Together they dictate how a blade will perform in a cutting operation.
All this is actually pretty ambiguous because none of our edges come to a perfect edge. The edge has width and rounding so it begs question of where it's measured; 1 micron back from the edge, 2 microns, 3 mm, etc. It's all so vague that when the minutia is considered it's almost impossible to nail down and since there is no standard I just don't go there.
So I have some questions: If we had the equipment to do it, could both a 15 dps edge and a 20 dps edge be 1 atom or molecule or whatever the smallest steel particle is wide? Is bevel angle a limiting factor in apex width or is this a limit of our ability to test it because bevel angle effects the test?
Of course for all intents and practical purposes this is academic and I doubt I'd notice when slicing an onion, but it is interesting nonetheless.