Long Term Viability of a Knife Edge (Metallurgic Theories)

[Marc H]

I’d like to invite conversation dealing with knife steels and their attributes and processes that may enhance or effect the Long Term Viability of the knife edge.   This may be due to improper manufacturing techniques, improper or poor hardening and cryo treatment of the steel, steel damage incurred while making the knives and damage incurred while sharpening.  Often situations arise where we see damage to the edge that is not the results of WEPS use.

Marc
(MarcH's Rack-Its)

3 users thanked author for this post.

Mark76, Organic, sksharp

[Josh]

Good post Marc! I was just reading in the other thread about damage from localized heat to the very apex (last few microns) of the edge by some work that Roman Landes had done. Here and Here on hypefreeblades it was also discussed, but I think the end results are inconclusive. The ‘study’ w/ the garden shears was not controlled enough (for example, what pressure was used, how long, how dull was the belt, what speeds, etc). Also, nothing was never done to show the relationship wet grinding had to dry grinding (if damage still occurred) or if grinding by hand and generating the 2000F temp actually did anything (which I doubt). The only way I believe you could tell a change in rc would be through testing the edge retention very carefully and very controlled, w/ many runs. But I think for day to day users none of this will be noticeable as long as sharpening (whether powered or non) is done carefully.

On a side note, speaking of de-stressing – this argument comes from damage extending below the apex simply from stropping (or use). I tend to agree that it can happen, however, normal sharpening will probably generally remove all this damage w/ out flattening your edge. But I’ve come across 2 interesting articles on this topic (edge damage below the surface). Here is one by Todd Simpson, and Here is one by Clay.

Todd notes,” It is important to remove this large burr with edge-leading strokes as the steel near the base off the burr will be damaged from the burr flipping side to side.” Has this ever been documented? I have heard others say that “stropping for maintenance” will result in less edge retention because of this, or like you said, burrs – will cause damage beyond the actual apex from the stress.”

Clay’s experiment simply shows that damage CAN happen through stress below the apex, but like I said I don’t think it’s usually an issue.

 

4 users thanked author for this post.

Mark76, Organic, sksharp, Marc H

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