11-03-2017, 01:34 PM
Correlating the visibility of edge apexes to a particular wavelength of light is great! Particularly so in view of the discussion of "dull". Now that is something new on the Exchange! Here's some trivia for you; why do we perceive an object to be blue, green, red etc.? Because that's the wavelength of light that the object reflects.
So let's talk about dull and the BESS a bit. The BESS scale uses, as a reference point, a standard DE razor blade blank (unsharpened) as the top end of the BESS (2000). A standard DE blank measures about .004" (4/1000ths) inch in thickness. Usually these dull blanks are manufactured by simply snapping the blade in half and measuring the broken side (in the center notch and not at the break). This is all a bit of backyard science though because we know that it is the corners of the broken DE blade edge that do the severing and not the flat apex (if apex is an appropriate term here). It's a handy reference point for an edge testing instrument but that's about all it's worth because, likely, if the DE blade were only .001" thick the same or similar measurement would result. By the way, we actually prefer butter knives. Many of them will yield readings in the 2000 range. It's just that DE razor blades yield a more ready and standardized result
There really is no way to express a value for the dullest edge just as there is no way to express the highest possible temperature. Fortunately, we all spend our time on the opposite end of the BESS where things can be better defined. The edges we deal with are very thin and that is the most important takeaway here. If someone in the past may have underestimated just how thin they really are then that is to be easily understood and quickly forgotten. The important point then, and now remains, that we are dealing with very small amounts of metal out there on the apex of these edges and that understanding will help make us better sharpeners and better sharpness testers.
Thanks to all here. BESS Exchange members raise the bar!
So let's talk about dull and the BESS a bit. The BESS scale uses, as a reference point, a standard DE razor blade blank (unsharpened) as the top end of the BESS (2000). A standard DE blank measures about .004" (4/1000ths) inch in thickness. Usually these dull blanks are manufactured by simply snapping the blade in half and measuring the broken side (in the center notch and not at the break). This is all a bit of backyard science though because we know that it is the corners of the broken DE blade edge that do the severing and not the flat apex (if apex is an appropriate term here). It's a handy reference point for an edge testing instrument but that's about all it's worth because, likely, if the DE blade were only .001" thick the same or similar measurement would result. By the way, we actually prefer butter knives. Many of them will yield readings in the 2000 range. It's just that DE razor blades yield a more ready and standardized result
There really is no way to express a value for the dullest edge just as there is no way to express the highest possible temperature. Fortunately, we all spend our time on the opposite end of the BESS where things can be better defined. The edges we deal with are very thin and that is the most important takeaway here. If someone in the past may have underestimated just how thin they really are then that is to be easily understood and quickly forgotten. The important point then, and now remains, that we are dealing with very small amounts of metal out there on the apex of these edges and that understanding will help make us better sharpeners and better sharpness testers.
Thanks to all here. BESS Exchange members raise the bar!