teach me about convex edges

[Twindog]

People say they hold their edge longer as there is more behind the edge, I say they hold their edge for a similar amount of time but the gometry is making it cut with less resistance

There can be more or less metal behind a convex edge, depending on how it is profiled. Sweeping generalizations comparing V edges to convex edges are meaningless unless you control for the actual profiles of the edges.

 

[Obsessed with Edges]

Amount of pressure needed to complete a cut can make a big difference in edge retention. Sounds obvious, but it explains why tailoring the level of refinement to the task/type of cutting action can make a large improvement in the functional lifetime of an edge.

I saw this with a cheap, imported grocery-store paring knife, on which I thinned the edge. I was using it for sharpening 'practice', and basically assumed the thinner edge I was putting on it wouldn't last very long. I used it as a steak knife often, and realized that the improved geometry was changing the way in which I could use the knife. No more need to lean into a cut, when slicing a steak on a stoneware plate. If done with a thick and poorly-slicing edge, more pressure is needed, and therefore more grinding of the edge against the plate (instant dull). With a better slicer, the pressure exerted is almost feather-light by comparison, and the edge doesn't make hard contact on the plate (if any). So, the net result is, the thinner edge cuts more efficiently for a longer period of time, even after the 'shaving sharpness' goes away.


David