I have a problem with sharpening one knife...

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lonestar1979

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Mar 2, 2014
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I have problem sharpening an older butcher-kitchen eicker solingen knife,have tried destressing the edge too,but it seems that blade somehow lost the temper or something.Even after taking the burr off the edge is barelly shaving and edge doesnt last at all.Knife was used my buself and also used,abused by others,also ground on beltsander-grinder before.Could it be that the temper is ruined,because these eicker solingen knives should take killer edge.I have been sharpening for 30 years and have no problem sharpening to hair shaving edge in no time.I used sil carbide norton stone on this knife.All input welcome.
 
Probably the heat generated by power sharpening took the temper out of the edge. Sharpen a bit of the spine near the tip to test the theory.
 
I think its the heat too,the edge just feels different,not crisp at all....just sharpened couple of wusthofs,love the way they take the edge along with mu victorinox knives.This eicker was used by my father in butcher plant for few years,and think it was sharpened there on power grinder,also used and abused in kitchen later,i reground it too some time ago,without paying attention on heat....
 
Might give it a chance, over another 2 or 3 (or 4) resets of the edge.

Since it's known the knife had been worked on grinders before, maybe badly, I'd also bet it's heat damaged. Might just have to keep taking bad steel off the edge, and hope it doesn't go too deep.

I've had some knives like that, which I swore were completely ruined. Even questioned whether one of them had been heat-treated at all. But eventually, after I'd reset/reprofiled the edge several times, the steel at the edge finally started looking stable and more 'normal' in terms of edge retention.
 
Many of those older kitchen knives are barely heat treated. I'd sharpen it up on the fine side of your Norton stone and steel it on a the edge of a smooth glass dish or rim of a glazed bowl etc - maybe a half dozen passes. A little work hardening/burnishing may be just what it needs.
 
You could do the edge flex test to see if the edge has been somewhat properly heat treated.

 
After getting burr,when i take it off,edge is just not razor sharp,barely shaves on some parts and some parts not.Seems like the steel is very weak at edge .
 
If you hold the edge at 90 degrees on a piece of wood and draw the blade sideways down the wood, scraping it, does the apex fold over?
 
lonestar1979 said:
After getting burr,when i take it off,edge is just not razor sharp,barely shaves on some parts and some parts not.Seems like the steel is very weak at edge .
Click to expand...

This is the type of behavior I've seen in heat-damaged edges; also in edges that've been 'aligned' on a kitchen steel for too long a time, after which that work-hardening effect eventually weakens the steel at the edge, and it must be removed. When the steel is that weak at the edge, it's as if the 'burr' (the weak steel) can never be removed, no matter how much of it you're taking off. Everything left behind it is still obviously weak and will move, fold or roll over in any attempts at cutting.

One of the knives I dealt with had an edge that could be shaped & honed to a crisp apex, which looked like it should cut very well. But I could run the edge of my thumbnail along the apex and actually see the apex fold over, as revealed by a bright strip of reflected light in the wake of my thumbnail's pressure. I had another one that, instead of rolling, the thin apex would just sort of crumble into dust in the first cut in anything. With both of these knives, I had to keep revisiting them with multiple reprofilings, before the edges began to appear more stable and behave normally.
 
Ill just throw this knife in garbage,have no desire to sharpen it multiple times just to get usable edge.
 
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