Knife edge won't last after sharpening

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coffeelover191919

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i can get a knife very sharp on the shapton 1k, 2k (also have the 5k, but i've been finishing on the 2k cuz i like the bite, but this applies to finishing on the 5k also)

After creating the burr on both sides of the knife with the shapton 1k, and removing it, then spending about 5 minutes on the shapton 2k, (then sometimes the 5k) the knife is very sharp. It can shave, it pings when i pull my fingertips across it, cuts paper smooth, tomato test, etc.

How do i get the sharp edge to last longer? I'm not talking about how long an edge lasts on white #2 < Blue #2 < AS. I feel that i can do better by having the edge last longer and i think it has to do with my sharpening.
 

Rangen

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Just a guess: you need to strop. Sharpening on a 2K or 5K is no guarantee that your sharp edge is not just a wire edge that will crumble easily.

A dozen or so edge-trailing strokes on some leather loaded with green compound or 4 micron diamond paste might, just possibly, sort things out.
 

coffeelover191919

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Just a guess: you need to strop. Sharpening on a 2K or 5K is no guarantee that your sharp edge is not just a wire edge that will crumble easily.

A dozen or so edge-trailing strokes on some leather loaded with green compound or 4 micron diamond paste might, just possibly, sort things out.
Oh, i do strop. I have a dual sides strop. One with green compound, one with bare leather. I bought Sepici leather from amazon and its very good quality.
What does stopping do to make your freshly sharpened edge last longer? (yes, i know it removes the burr, but i also removed it on the shapton 1k / 2k
 

ian

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How long are your edges lasting? If they degrade basically as soon as they hit the board, then yea, you didn’t deburr correctly. What deburring techniques are you using?
 

ian

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The thing is, I’m not sure that stropping is the best way to remove a big old wire edge, if that’s what’s happening. Rather, work on your stone deburring technique, and then strop to get rid of the very last burr remnants and clean up the apex, if that’s your jam.

There are a bunch of good deburring methods out there. Edge leading strokes help, there’s the horizontal pull method in the JKI deburring vid, and there’s Kippngton’s method, which I find can be particularly helpful for steels that form tenacious burrs. Make sure that you’re using extremely light pressure at the end.
 

Nemo

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It does sound a bit like a wire edge.

Burr control and burr removal was my first big hurdle after I learned to make a decent edge.

Can you describe for us how you "remove the burr"?

Also, 5 mins on a 2k or 5k seems a bit excessive if you have already created a well apexed, deburred edge on a 1k. By far, most of the work should be done on the coarsest stone that you will use in that pogression.

You may want to look at @Sailor 's video on pressure control. It's in his knifeplanet.net sharpening school but it is (or at least was when I found it), the last video in the JKI sharpening series. It essentially says that you should abrade the burr by gradually reducing pressure on your coarsest stone. You should only be polishing the edge WITH VERY LIGHT PRESSURE on all subsequent stones.
 

ian

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Also, 5 mins on a 2k or 5k seems a bit excessive if you have already created a well apexed, deburred edge on a 1k.
Yea, I was gonna say that too. Think more like around a minute or two on the 2k, although if you’re efficient it could be even less. And tbh I would skip the 2k and spend the minute on the 5k....
 

Unstoppabo

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Maybe sharpen at a slightly higher angle or slap on a microbevel? When I first sharpening on stones, I tried to go as low as possible but now I'm around 40 degrees total and it makes a big difference. On gyuto's I'm usually around 15 on the right side but probably around 25 on the left. Still feels super sharp as long as the knife is thin behind the edge.
 

Ruso

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How long does your edge last? Did I miss this information?
 

M1k3

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Every time someone posts this video I end up watching it.
I like sharing it. I was getting good results before. But after getting it down, it was noticeably better.
 

TSF415

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I like sharing it. I was getting good results before. But after getting it down, it was noticeably better.
Well I went from ok results to good results. I think I’ll eventually make it into the great results category.

Edge leading has definitely given my the biggest improvement in sharpening compared to other techniques I’ve tried.

and when you post that video again, I will watch it again
 

Nemo

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Well I went from ok results to good results. I think I’ll eventually make it into the great results category.

Edge leading has definitely given my the biggest improvement in sharpening compared to other techniques I’ve tried.

and when you post that video again, I will watch it again
OK:



Sorry, couldn't resist.

:D
 

nexus1935

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Thanks for sharing that video! Always better to see the edge-leading strokes in action (I've been recommended it before, but I've been hesitant that I would do it wrong).
 

Garm

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When you start to lose sharpness, have you examined the edge to determine what it looks like or feels like?
For instance, does the edge roll to one side or different sides in various sections, can you see light reflections, does the apex just feel rounded etc?
These issues can give some indications to where the problem lies. Wire edge, angle consistency during sharpening or during burr removal, sporadic burr remnants and so on.
 

kayman67

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Wire edge/weak edge can also be solved to some extent (with experience to any extent) with a very hard natural stone, like a hard ark. It's slow enough not to generate new problems, too.
 
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