The “micro-serrations” concept contributes to the confusion as people tend to mistakenly generalize properties of the serrated edge onto the microscopic level of a ragged coarse edge. The saw teeth and the edge ragged by a coarse abrasive are not the same. This myth about blades having "teeth" formed by the "scratches" on the bevel just won't die. Coarse scratches do not create "teeth" on the apex. In the edge sharpened coarse, the high spots are mostly burrs and the low spots are mostly chips far wider than any given scratch; after deburring you get an irregular apex riddled with flaws. A knife edge sharpened to rougher finishes will have larger scratches than a finely honed edge, and these scratches can be thought of as pre-existing flaws; the sub-surface damage is also more pronounced and extended. A coarser edge does “bite” initially, however the knife dulls faster as the “teeth” get broken off, and as the edge chipping develops along those flaws. The following SEM micrographs of a coarse “toothy” edge show the scratches. The metal near and below each scratch is damaged, e.g. damaged area from the grit 200 extends to 4 microns below the surface in hardened steel. This damaged metal must be honed away with finer grits, because if you leave it coarse, as you start cutting, the load will ruin the edge over the damaged areas, as shown on the following edge-on SEM. (By courtesy of Sandvik) Thoroughly done studies have shown that the coarse finish is associated with increased grip force, cutting effort and cutting time, and worse edge retention. In precise cutting and carving unpolished bevels cause traction in cuts and lower accuracy and quality of cut. Meat plants are well aware that knives with coarse edges worsen product presentation and increase operators’ fatigue and repetitive strain injuries. On the contrary, polished edges improve product quality through higher value cuts and increase throughput. Premium wear-resistant knife steels are plainly incompatible with unpolished edge, as explained later in our book in the chapter on high-end knives.
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). I just don't find that jumping from something coarse, like a 400, to a strop consistently gives a clean apex that's free of burr.
