Thread: The goal of polishing the edge?

Originally Posted by bjanzen

I am still baffled on that blade. I worked and worked to get it to cut arm hair at 4K. Never did. My other blade had 10 X strokes on 1k, then 10 X strokes on 4K and was popping arm hair. This one never would. I honed and honed and no luck. It was nice and sticky with the TPT and looked like a great bevel under the 100x scope view. Finally I decided to just finish the honing and test shaved after 8K and no luck. Wouldn't pop arm hair. The other blade was incredible after 8K. Finally after the polishing on CromOx it started cutting. Seemed like the better shaver of the two blades!

I have no clue, if anyone figures this out I would love know why also; mostly because what you did is exactly what I do, of course I don't know too much but seems like it should have worked. Wonder if it is the difference in steel used in the blade construction or something like that? Maybe just a stubborn razor?

I think of it this way: If I took a sheet of aluminum foil and folded it in half making a 17 degree wedge and then subjected that edge to impact with some object, the edge would sustain an amount of damage. If I somehow fashioned that same edge in a sheet of foil but added peaks and valleys (striations), in effect creating an appearance similar to an accordion bellows running perpendicular to the edge, I believe the striations would add rigidity to that edge. Again, I could be completely off base with these thoughts but that's they way I have visualized this for some time.

The only reason that holds for Al foil is because the foil is essentially 2D, and the striations add thickness. I beams are more rigid than thin flat beams, but much less rigid than the thick block that would encompass the I beam.

Razor edges are solid steel, so digging striations in can only hurt.

It actually gets a bit worse than that, since sharp edges produce stress concentrations that can greatly weaken things. Glass cutters are the extreme example.

Now, its possible that theres some funniness going on with the grain structure that causes polished edges to be weaker, but at the homogeneous level, that's not how it works.

I find it much more likely that the explanation is that smoother edges are nicer so that a smaller degradation in performance if more noticeable or that the striations help slice hairs even when at a lower push cutting sharpness, or something like that.