# Knife edge won't last after sharpening



## coffeelover191919 (Jul 9, 2020)

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.


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## Rangen (Jul 9, 2020)

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.


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## coffeelover191919 (Jul 9, 2020)

Rangen said:


> 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


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## ian (Jul 9, 2020)

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?


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## jacko9 (Jul 9, 2020)

I strop every knife I own before use.


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## ian (Jul 9, 2020)

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.


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## Nemo (Jul 9, 2020)

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.


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## ian (Jul 9, 2020)

Nemo said:


> 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....


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## Unstoppabo (Jul 9, 2020)

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.


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## M1k3 (Jul 9, 2020)




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## TSF415 (Jul 9, 2020)

M1k3 said:


>




Every time someone posts this video I end up watching it.


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## Ruso (Jul 9, 2020)

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


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## M1k3 (Jul 10, 2020)

TSF415 said:


> 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.


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## TSF415 (Jul 10, 2020)

M1k3 said:


> 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


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## Nemo (Jul 10, 2020)

TSF415 said:


> 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.


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## TSF415 (Jul 10, 2020)

Nemo said:


> OK:
> 
> 
> 
> ...



Damnit. But this is the last time for today


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## M1k3 (Jul 10, 2020)

TSF415 said:


> Damnit. But this is the last time for today


But it wasn't me posting it


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## M1k3 (Jul 10, 2020)

TSF415 said:


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


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## nexus1935 (Jul 10, 2020)

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).


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## TSF415 (Jul 10, 2020)

M1k3 said:


> But it wasn't me posting it



Well you guys sure no how to ruin a good thing.


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## lechef (Jul 10, 2020)

M1k3 said:


>




First time seeing this. Very helpful and explains a lot of the issues I was dealing with last weeks after getting back into sharpening.


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## M1k3 (Jul 10, 2020)

Real credit goes to @stringer


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## Garm (Jul 10, 2020)

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.


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## kayman67 (Jul 10, 2020)

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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## amithrain (Jul 10, 2020)

M1k3 said:


>



What are you linking? I can’t see it, I’m on mobile :/


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## M1k3 (Jul 10, 2020)

amithrain said:


> What are you linking? I can’t see it, I’m on mobile :/


@stringer demonstrating edge leading strokes


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## Ruso (Jul 10, 2020)

M1k3 said:


> @stringer demonstrating edge leading strokes


So it’s like edge trailing but leading instead?


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## ian (Jul 10, 2020)

Ruso said:


> So it’s like edge trailing but leading instead?



Objection. That was a leading question.


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## M1k3 (Jul 10, 2020)

ian said:


> Objection. That was a leading question.


Sustained!


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## kayman67 (Jul 10, 2020)

Obviously. It's all filmed in reverse. That's how I do my edge trailing anyway.


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## ModRQC (Jul 10, 2020)

One question the OP still didn’t answer is how fast the edge fails. Burrs/wire edges are often the problem of less experienced sharpeners, but is that what is going on here or not? 

Since the OP only recently started sharpening as I recall, I’d be tempted to say they must all have failed (his edges) quite fast, but who knows how and how long the knives are actually used or abused?


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## nwshull (Jul 10, 2020)

In addition to the advice about edge trailing strokes, try running the knife through hard felt if you have it, if not a wine cork several times.


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## ian (Jul 10, 2020)

@coffeelover191919, don’t be scared of all these nasty people screaming deburring advice. We’re really not that bad. Come back!

Are there really people that don’t check KKF every 10 minutes?


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## inferno (Jul 10, 2020)

it could also be that the steel simply dont last any longer than what you are getting. 

straight off the stone sharpness last for like 5 minutes usually. just so you know. then it reverts to like 70-80% of that. powder SS can hold that 70% forever. carbon not so much. it just gets worse and worse in a linear fashion. 

no one can really answer this question. you simply have to find out for yourself to be honest. and adjust accordingly.


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## ModRQC (Jul 10, 2020)

It would help to know if it fails instantly or not, another problem entirely that is easily remedied... but all this... it's just wind right now.


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## inferno (Jul 10, 2020)

probably the OP will find out whats really going on by simply looking at the edge closely. yeah it might sound stupid but seriously if you simply look at the edge you will see why its not sharp anymore, how it dulled. and you will also see how well you have sharpened it. use a loupe, scope or magnifying glass if you have to. i dont have to, i'm at -10 diopter from the start so i can focus on **** 4-5cm in front of my eyes. when i was young i could read text at 2cm (and only 2cm) beyond 2cm it would all get unsharp and hazy the further you went. i guess i was made for close up precision work


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## Shing Chan (Jul 11, 2020)

Do you know how hard the blade is? Some blades are quite soft such as Rc 52 or Rc54. While they can be made very sharp, the soft steel doesn't hold the edge very well and soon loses it and need frequent sharpening. Some European knives can be quite soft by design so they are easy to touch up on a steel.


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## danemonji (Jul 11, 2020)

Depends on the angle he sharps his knife at, the steel hardness and very important what cutting board he uses. In Japan it is common to use a microbevel for edge retention, if the knife is very thin at the edge. Just check out some videos on how to put on a microbevel.
Also try to use end grain cutting boards or rubber( Hasegawa). Even if the steel is on the soft side, it should hold up ok with a microbevel and a good cutting board.


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## Shing Chan (Jul 11, 2020)

danemonji said:


> Depends on the angle he sharps his knife at, the steel hardness and very important what cutting board he uses. In Japan it is common to use a microbevel for edge retention, if the knife is very thin at the edge. Just check out some videos on how to put on a microbevel.
> Also try to use end grain cutting boards or rubber( Hasegawa). Even if the steel is on the soft side, it should hold up ok with a microbevel and a good cutting board.


We need more information.


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## ian (Jul 11, 2020)

Yea, probably the commentary should go on hold till the OP returns.


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## M1k3 (Jul 11, 2020)

Input, more input!


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## coffeelover191919 (Jul 15, 2020)

inferno said:


> *it could also be that the steel simply dont last any longer than what you are getting.
> 
> straight off the stone sharpness last for like 5 minutes usually. just so you know. then it reverts to like 70-80% of that. powder SS can hold that 70% forever. carbon not so much. it just gets worse and worse in a linear fashion.*
> 
> no one can really answer this question. you simply have to find out for yourself to be honest. and adjust accordingly.


Sounds like my problem. Knife is super razor sharp right after a 2k stone and maybe a strop (mostly not) after a 3 uses, i already lose that feeling. maybe i'm just spoiled by the fresh off the stone sharpness. 

Both of my main gyutos are AS, one from Anryu, one from Yoshihiro. So the steel should be quite long lasting. Maybe my next knife i should look into a powedered SS. What maker and steel would be best for that?


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## TSF415 (Jul 15, 2020)

coffeelover191919 said:


> Sounds like my problem. Knife is super razor sharp right after a 2k stone and maybe a strop (mostly not) after a 3 uses, i already lose that feeling. maybe i'm just spoiled by the fresh off the stone sharpness.
> 
> Both of my main gyutos are AS, one from Anryu, one from Yoshihiro. So the steel should be quite long lasting. Maybe my next knife i should look into a powedered SS. What maker and steel would be best for that?



Do you do the light test to make sure there's light reflecting on the edge of the knife?


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## ModRQC (Jul 15, 2020)

coffeelover191919 said:


> Sounds like my problem. Knife is super razor sharp right after a 2k stone and maybe a strop (mostly not) after a 3 uses, i already lose that feeling. maybe i'm just spoiled by the fresh off the stone sharpness.
> 
> Both of my main gyutos are AS, one from Anryu, one from Yoshihiro. So the steel should be quite long lasting. Maybe my next knife i should look into a powedered SS. What maker and steel would be best for that?



No trouble with AS my friend, powdered steel ain’t nothing so good to compare except edge retention, and if your AS edge doesn’t hold it is not a matter of retention.

How do you cut, and on what type of surface, just so we have a whole ballpark of your use?

Edit: you’re not the OP so let that go. And BTW when you wash your AS knives dry the very edge dragging through the towel’s hem. Microscopic drops of water still clinging on the very edge eats away the fresh edge in storage time.


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## coffeelover191919 (Jul 15, 2020)

TSF415 said:


> Do you do the light test to make sure there's light reflecting on the edge of the knife?


 no, what's that? 


ModRQC said:


> No trouble with AS my friend, powdered steel ain’t nothing so good to compare except edge retention, and if your AS edge doesn’t hold it is not a matter of retention.
> 
> How do you cut, and on what type of surface, just so we have a whole ballpark of your use?
> 
> Edit: you’re not the OP so let that go. And BTW when you wash your AS knives dry the very edge dragging through the towel’s hem. Microscopic drops of water still clinging on the very edge eats away the fresh edge in storage time.


Wait, I am op. 

I slice and dice on a Hasegawa sold core cutting board from MTC Kitchen. Occasionally (10%) on an acacia wood cutting board from crate and barrel. 

I dry my towels pretty good using an ikea towel and it never stays wet for more than 5 mins max 10.


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## ModRQC (Jul 16, 2020)

Sorry mixing threads you’re the OP. 

What cutting technique is your default?

And I really meant: dragging the whole length of the edge through the hem of the towel. Drying on surface - and yes not cutting your hand or the whole towel - doesn’t always dry the very edge exactly because you are wary not to. When both sides are dried thoughout, go to the hem on a corner and gently glide the whole edge as if cutting it. It will penetrate but won’t go through with very light pressure. The very edge will be dry. 

And I think what @TSF415 meant is do you check the edge against a direct strong light to verify that there are NO light reflecting on it? Light reflecting means a burr remnant or a spot where the edge wasn’t correctly apexed.


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## coffeelover191919 (Jul 16, 2020)

ModRQC said:


> Sorry mixing threads you’re the OP.
> 
> What cutting technique is your default?
> 
> And I really meant: dragging the whole length of the edge through the hem of the towel. Drying on surface - and yes not cutting your hand or the whole towel - doesn’t always dry the very edge exactly because you are wary not to. When both sides are dried thoughout, go to the hem on a corner and gently glide the whole edge as if cutting it. It will penetrate but won’t go through with very light pressure. The very edge will be dry.


Correct me if i'm wrong, but after washing. run the edge of the knife 90 degrees against an edge of a towel to dry very lightly, as if i was trying to slice through it? Wouldn't this dull the edge of my knife?




ModRQC said:


> And I think what @TSF415 meant is do you check the edge against a direct strong light to verify that there are NO light reflecting on it? Light reflecting means a burr remnant or a spot where the edge wasn’t correctly apexed.


Will hold up the edge of the knife to some strong light next time to see what it looks like, but not quite sure what to look for.


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## ian (Jul 16, 2020)

coffeelover191919 said:


> Correct me if i'm wrong, but after washing. run the edge of the knife 90 degrees against an edge of a towel to dry very lightly, as if i was trying to slice through it? Wouldn't this dull the edge of my knife?



My usual way to make sure the knife is dry is to just wipe it on the side of a paper towel roll after drying it with a towel. If you're really worried about microscopic droplets on the edge, you can make sure you're hitting the edge when you do this, essentially stropping (edge trailing stroke) on the paper towel roll. I'm not convinced that microscopic droplets on the edge are a problem though, even with white steel knives, much less AS. I mean, they're going to evaporate like instantaneously.



coffeelover191919 said:


> Will hold up the edge of the knife to some strong light next time to see what it looks like, but not quite sure what to look for.



Just looks for inconsistencies. The edge should look uniform all the way up and down. If there are little spots when you hold it to the light, that's bad.


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## ModRQC (Jul 16, 2020)

coffeelover191919 said:


> Correct me if i'm wrong, but after washing. run the edge of the knife 90 degrees against an edge of a towel to dry very lightly, as if i was trying to slice through it? Wouldn't this dull the edge of my knife?
> 
> 
> 
> Will hold up the edge of the knife to some strong light next time to see what it looks like, but not quite sure what to look for.



No it won't dull it. Ian's way with the paper towel roll is a nice alternative - but since you can't avoid a towel when drying, the hem does just fine of it. Granted, as per Ian, AS is far from being the most corrosive carbon steel, but I just wanted to verify that you still applied some basic care to the edge, especially if cutting a lot of acidic stuff.

As for the light I'll admit it doesn't come naturally the first couple of times. Look under direct light, directly at it. No light should reflect from the apex. You might think at first it's reflections coming from the bevel or something, but if the blade is held perpendicular to your face, spine down, under direct light, the only reflections that can happen are ill apex or burr remnant. Trust that it is what you see, and make it a part of every stone in any progression in the deburring process.

Of course, blade has to be clean and dry, with no specs of dust or towel/paper sharpie (they might look like an inconsistency and lead you astray). I made a habit to lightly blow at the edge to remove any dust or residual towel sharpie before looking.


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## coffeelover191919 (Jul 16, 2020)

Maybe i'm just chasing that unicorn, fresh off the stone sharpness. It feels amazing and i'm super happy with the way the edge feels after a 2k stone. Smooth slicing paper, passes tomato test, good enough for all foods.

After about 5 uses, i'd say the knife is still sharp by a laymen's standard, just doesn't have that off the stone feeling. Normal?


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## ModRQC (Jul 16, 2020)

Absolutely. Then refresh your edge with light touch ups about each 2-3 preps and you’ll keep happy longer.


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## jacko9 (Jul 16, 2020)

Unless you do major damage to your edge, just strop it with something like 0.075 micron CBN paste.


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## TSF415 (Jul 16, 2020)

coffeelover191919 said:


> no, what's that?
> 
> Wait, I am op.
> 
> ...



Check out Peter Nowlan's @Sailor videos. He stresses the light test all the time. As I get better at sharpening this has really helped me.


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## ModRQC (Jul 17, 2020)

@Sailor video is a game changer, especially the first one a newcomer could stop right there, and not watch anything else. A no nonsense basic progression, and he does it in a way that seems so straightforward you'll feel confident you can do it too.


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## jacko9 (Jul 17, 2020)

When I first purchased my Konosuke HD2 from Tosho Knife Arts I asked Olivia about sharpening and Ivan was there at the time and when I mentioned just using the strop Ivan thought that was a great idea and wondered how long the edge would last that way. With light use of the knife I didn't take it to a 1K stone for a few years and never at a lower grit. I think people rush to their sharpening stones way too soon.


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## Garm (Jul 17, 2020)

jacko9 said:


> Unless you do major damage to your edge, just strop it with something like 0.075 micron CBN paste.


That sounds way too fine for kitchen use, unless you mistyped. Seven and a half hundredths of a micron?


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## VICTOR J CREAZZI (Jul 17, 2020)

Garm said:


> That sounds way too fine for kitchen use, unless you mistyped. Seven and a half hundredths of a micron?


I was thinking the same thing.


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## Nemo (Jul 17, 2020)

TSF415 said:


> Check out Peter Nowlan's @Sailor videos. He stresses the light test all the time. As I get better at sharpening this has really helped me.


I fisrst learned the light test when learning to sharpen saw chains. Works on knives as well. If you can see light reflect off the very edge, it means that it's not a clean edge at that point. Either not apexed, has a residual burr or has a chip.


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## jacko9 (Jul 17, 2020)

Mistake it's - .75 micron CBN


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## Benuser (Jul 18, 2020)

ModRQC said:


> Absolutely. Then refresh your edge with light touch ups about each 2-3 preps and you’ll keep happy longer.


A few edge leading strokes will do, as if you were deburring. I use a small piece of Belgian Blue Brocken.


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## inferno (Jul 19, 2020)

coffeelover191919 said:


> Maybe i'm just chasing that unicorn, fresh off the stone sharpness. It feels amazing and i'm super happy with the way the edge feels after a 2k stone. Smooth slicing paper, passes tomato test, good enough for all foods.
> 
> After about 5 uses, i'd say the knife is still sharp by a laymen's standard, just doesn't have that off the stone feeling. Normal?



it could be that ultra sharpness goes away that fast. i dont know. 
all i know is that carbon steels lose sharpness pretty fast unless you baby them, but its easy/fast to get them back to ultra sharp. 
while SS dont usually even get that sharp to even begin with, but they degrade slower. and they are slower to touch up.
the powder ss / powder ss-hss like r2 and srs15 kinds splits it in the middle. they usually get a bit sharper than maybe vg10 and similar (but not more than aeb-l/13c26, this is razor steel), and they degrade a bit slower and they kinda revert to a level above the regular ss and keeps that for quite some time. 

to be honest i dont know how in a home environment i would be able to dull srs15 or r2 so it wont cut paper anymore. it would probably take me a year or so. but it will lose that fresh ultra sharpness pretty fast though. and it also takes a much much longer time to sharpen these babies up again. like 10 times longer.
blue super is like butter in comparison.


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