# How sharp do you keep your knives?



## Boynutman (May 22, 2016)

I am wondering what day-to-day sharpness I should (can?) aim for for my kitchen knives, which are 4 different gyutos. When I do my best I can get them arm-hair-shaving sharp - haven't been able to achieve paper-towel-push-cut-sharp. But based on some ideas on the forum I now tend to stop at 2k with micro bevel (5k is the only higher grit I have), so that the edge keeps some toothiness. Probably not the best grit for shaving... But anyway, that sharpness is just after sharpening. Generally happy with the performance while preparing food. I am a home cook, light use only, and after some use I now strop on the 5k.

I see and read all this stuff here about super super sharp (I have come to realize that I am not yet fully proficient in free hand), but seriously, how sharp do you keep your knives for daily use? And how do you achieve that? And is it proper sharpening and then they keep like that a long time, or do you strop every time before cooking?

I guess I am not sure what to expect or aim for. I read so much stuff here about REALLY sharp knives that I am wondering whether in real life people live with less extreme sharpness once the knife has been used a few times after sharpening. I understand there is some OCD out there... certainly not immune to that but also feel a little self conscious when I bring out my stones again... (yes, daddy's married with children!).

Would appreciate your thoughts!
(I hope I haven't missed a similar thread but couldn't find it!).


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## mc2442 (May 22, 2016)

As a fellow home cook with too many knives, I don't have to sharpen that often. The exception that ends up grating on me, however, is a DT ITK petty that is the only knife that a housemate ends up using (so much more than the others that I spread around), that I have to sharpen now and then as friends just now assume that everything I own is sharp as hell.

To answer your question, I do like to keep everything arm hair shaving/magazine paper clean cutting sharp.

Expectations are out there though by people that are not that familiar with things. I recently sharpened a friends relatively new knife that actually had a damn sharp edge to it...I am sure my edge will last a whole lot longer but I am not sure how much sharper I was able to get it.


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## Kippington (May 22, 2016)

I'm a pro cook that used to be obsessed with sharpness.

5 years ago I would sharpen to a 0.1 micron strop at the end of every day. Nowadays I spend less time at each sharpen, but I do it much more frequently. Anytime you'd see a normal chef use a steel, I'd take out a stone instead and spend about a minute sharpening it up (no more stropping, just a splash-and-go polishing stone).

When it comes to how sharp I'm aiming for, many people have previously pointed out that a knife needs to be sharp enough to get the job done.
How does this translate into the real world? The best way to describe it is to think of the cutting job you do that is the most demanding on sharpness, and sharpen your knife well enough to do that job easily. For me it is cutting though a stack of pepper/chili/capsicum skins, layered on top of each other, in one slice. If my knife is sharp enough to do this then I am happy. HOWEVER, most other tasks won't need that level of sharpness so I'll do the jobs that need a very sharp knife first, then as the edge wears down I will move on to other cutting tasks where it is not so important.

FWIW I use a 67HRC ZDP knife at work, and even still I quickly touch up the edge on the polishing stone after every few hours. My obsession with sharpness hasn't so much gone - more evolved over time.


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## LifeByA1000Cuts (May 22, 2016)

My usual rule to keep sponges and knives fresh: If the knife does not cleanly slice into the sponge when cleaning it, time to hone or sharpen it. Massively sliced into sponges don't live too long next to the sink because they become awkward to use (but are perfect for cleaning up floor or stove spills) - this might not be super eco thinking, but they are under a buck for a pack of six here, so I certainly consider them disposables.

Discovered the technique before ever watching https://www.youtube.com/watch?v=W8rg71EadPQ , the Makesushi Myabi presentation - I have not a Shun nor a Myabi, but I hope the Shun is not factory new and failing that test, I don't think "don't expect perfect ootb edge unless you ordered a honbazuke knife, or from a brand/trader with a named sharpener" should be applicable to a brand that also caters to western beginners 

Generally, I appreciate whatever I cut to be through in one movement.

EDIT: punctuation, and found embedding the video that is not the main reason for my post too "loud".


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## 99Limited (May 22, 2016)

I'm a home cook and I have two knives that I use multiple times everyday day. I like to keep my knives as sharp as possible. I'll either strop them on leather or a 5k stone once or twice a week. Since they hold an edge my routine doesn't take but two or three minutes at a time.


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## Boynutman (May 23, 2016)

Thanks guys.

This is the kind of feedback I was hoping for, for me it puts things in perspective. The intervals for stropping you mention make me think I am not doing that bad. 
Also 2 of the knives I have are vg10 and I think I have had some issues with insufficient deburring resulting in poor cutting performance in a short time frame. 
The R2 pm knife appears to be less critical with that. 
The UX10 is still not fully what I had hoped for and I am thinking that too comes down to sharpening skill and not the knife itself.

Appreciate you taking the time to respond!


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## El Pescador (May 23, 2016)

Pro cook to now home cook. I sharpen once in a blue moon but tend to strop every week/every other week, either trailing strokes on a high grit stone like my JKI 6K diamond or on a green loaded leather strop. Stropping is really what we should do as home cooks. I used to sharpen a bunch when I started out but I realized I kept running out of knives! Now I sharpen to pull out chips on the edge. I also like a toothy edge (1k diamond to 6k diamond training strokes) so I can go much longer before I need to sharped compared to someone who likes a 6K+ edge on their gear.


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## LifeByA1000Cuts (May 23, 2016)

@Boynutman tried microbevelling the VG10? 

Found that to work well on a very stubborn VG10 knife that otherwise always stopped just short of shaving 

http://www.kitchenknifeforums.com/showthread.php/19462-What-are-your-experiences-with-VG10 Benuser seems to be right on the money - And microbevelling has the side effect of abrasively removing the burr and/or smoothing out a damaged apex.


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## clsm1955 (May 24, 2016)

I'm a home cook. For most of my knives a 6k stone is as fine as I need to go (I use a Gesshin 6000s). I strop after every 2-3 uses on a leather paddle loaded with .5 micron diamond paste and I have an edge that can cut a hanging hair but still lasts pretty well.


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## Boynutman (May 24, 2016)

Thanks for the further input. 

@1000Cuts, indeed I microbevel my Hattori HD 240 guyto (vg10) on a 5k stone (I have the Naniwa SS 2k/5k combi stone, if that makes any difference), I estimate somewhere between 30-40 degs. Took the advice and technique from Jon's excellent video. 
That vg10 thread was very informative!

For sharpening I am now stopping at 2k - I got the impression that the polished edge the 5k gave didn't help cutting performance.

In practice I am still disappointed how quick the knife stops gliding through said pepper/chili/etc. skins. I get through it but there is noticeable performance degradation. And once you have experienced good sharpness it is frustrating to feel it is partly gone. Maybe I am just fingering that edge too much....?
I check the edge with a 20x loupe to verify what I have done and the edge looks pretty clean after sharpening & microbevelling so I am thinking the bur is gone but maybe it's just almost gone, not quite.

I will start experimenting with more frequent stropping - that leather paddle set up sounds very promising.
(I must admit that when I first read about the leather stropping I was thinking this was bordering on new age style wishful thinking! "Steel on leather? Really?! Come oooon guys!". But it makes sense now).

Thanks again guys!


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## LifeByA1000Cuts (May 24, 2016)

I have a 10x stereo microscope (just a science geek, didn't buy it as a sharpening aid) and openly admit I cannot tell a shaving sharp from an OK sharp edge that way.

That VG10 thread says "don't try stropping the burr off" 

...

https://www.dictum.com/en/knives/traditional-hocho/719217/small-knife-with-sheath-all-purpose-knife show the same phenomenon - microbevel them and only then they shave (a very cheap knife I like for some tasks because it is so thin spined yet not super floppy. Suspecting the core layer is VG-2, which would agree with the imprint "V2" - cannot be V2 steel since it is stainless! - and the hardness specified).

... That quick sharpness loss can also be from bad storage options - eg plastic straw blocks get damaged by something that sharp, and they WILL damage the edge right back.


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## Kippington (May 24, 2016)

Boynutman said:


> In practice I am still disappointed how quick the knife stops gliding through said pepper/chili/etc. skins. I get through it but there is noticeable performance degradation. And once you have experienced good sharpness it is frustrating to feel it is partly gone. Maybe I am just fingering that edge too much....?
> 
> I will start experimenting with more frequent stropping - that leather paddle set up sounds very promising.



There's a good chance you're trying to chase the 'fresh off the stones/strops' feeling of sharpness, which never lasts long during actual use. There's no concrete answer in getting it to last longer, it involves too many factors including your sharpening skills, grit choices, the knife in question and your cutting skills.

Stropping might help, but it might not. As I mentioned in my previous post, I ditched stropping in favor of using a stone more often because the knife was sharp enough to do the job without it. Stropping wont increase the longevity of the edge for me. It did help for a while, but after my skills on the stones improved over time, stropping only served to make my knives sharper then I practically needed.

I also mentioned I need to bring out a polishing stone after every couple of hours of cutting prep. That's basically how often my knife loses its 'off the stones' feel during work use. A home user should try to keep that same feel after preparing one full meal, longer if possible.

Keep experimenting, its the only way to improve!


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## LifeByA1000Cuts (May 25, 2016)

Ironically, I find the W#1 Goko (the steel that should have the lowest edge retention  to be the one knife that most often still has some unexpected shave in it after actually dealing with a fridgeload of produce... However, only using a polishing stone to touch that one up seems to be the wrongest thing to do with it, that gives you a very short lasting edge (burnishing down tired metal I guess)..


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## Boynutman (May 25, 2016)

This has all been very useful feedback for me. It has put my own experience in perspective and now I have some ideas to try out to improve and maintain day to day sharpness. I will definitely experiment some with leather stropping, but I also understand regular light sharpening/polishing is an option as @Kippington suggests.

@1000cuts good feedback on the microscope - I also just had to see for myself (...and now that I can see it I am still not 100% sure how 'my' perfect edge would look like!).

Thanks all, really happy with this!


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## spoiledbroth (May 25, 2016)

A big part of edge retention depends on how you use the knife: technique, what are you cutting on, what are you cutting etc. Above all else you should always be using your knife with a light touch with a few specific exceptions.


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## Vangelis (May 26, 2016)

It really depends, I am a home cook leaving together with non knife nuts (at the best case) or knife illiterates (at the worst case), thus I must keep a balance. 

My knives are separated in two categories the one I will use exclusively and the ones considered as "common".

For the common ones, I will rarely touch them. I will only sharpen them when will reach a point that are almost blunt.

For the ones that I am using, I will strop them before and after use on a leather made strop without any compound and once and while will take them to the finishing stones if the knife doesn't cut as I expect to do. But it doesn't happen that often. 

Now the progression I will use to each knife will be different based on the use. Up to 1000 grit i am using synthetic and afterwards it is JNAT.


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## mikedtran (May 26, 2016)

For touchups I usually do a couple strops on a high grit natural or JNS 6000. For stainless I will usually strop on Cris Anderson's stone or JNS Aoto.

When sharpening I usually go from JNS 1000 to JNS 6000 with a final strop on Cris' stone or a high grit natural.

Though right now I'm leaning towards less polish - I did a sharpening session last night and only used my Blue Aoto. Knives were sharp enough to shave hair.


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## LifeByA1000Cuts (May 26, 2016)

There is an urge to leave kitchen guests with dropped jaws when they try a knife (and in some cases, obviously extreme sharpness proves to people you do not want handling them that these are indeed not just random knives with strange handles), and a wish to get the most performance possible out of comparatively expensive and maintenance intensive tools... what would be wrong with that?


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## Keith Sinclair (May 26, 2016)

These days my smaller blades are carbon regular size Gyuto's quality stainless. Since I have 3 240 stainless gyuto's on my magblock when one gets less sharp will grab the next one. I did this at work too spare gyuto's. At home using endgrain with less use edges last much longer than plastic boards at work.

Then to save time I sharpen all of them at once on a stand alone 4K Gesshin soaker. They are all trained so does not take long at all to hair shaving sharp. Finish them off with leather strop. Do not steel or strop at all between trips to the stone.


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## spoiledbroth (May 27, 2016)

keithsaltydog said:


> Do not steel or strop at all between trips to the stone.


this is me.

if I grind a good edge at the beginning of the week @1k then I could sometimes get away without touching up the edge for a full week. my tojiro dp 240 gyuto is really the only knife I use at the moment. So on sunday night I will do bester 1k and rika 5k. If I do a bad job grinding the new edge for the week or cutting alot of kabocha or yam I will usually touch up every day or every other day on the rika when I get home from work. But I really mean touch up it's just a few strokes edge trailing and edge leading and then Jon's perpendicular deburring technique. Draw through cork and verify on arm hair. I don't have vegetables or any "fresh" food around home anymore. :wink:


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## Boynutman (May 27, 2016)

So if it is just a few 1k + 5k strokes every week, is that basically a perpetual thing and no other sharpening is required? (that is apart from thinning which would eventually be required I assume).
Or is there some point in time where you would need to go back to a coarser stone and set up a new edge?
And do you deliberately raise a burr during these touch ups, or is it just that you know from practice a few strokes will work anyhow so no bothering about this?


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## Smurfmacaw (May 27, 2016)

spoiledbroth said:


> this is me.
> 
> i Jon's perpendicular deburring technique. :wink:



Ok, I'm lazy....perpendicular deburring technique? Link....pretty please :biggrin:


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## Kippington (May 27, 2016)

Boynutman said:


> So if it is just a few 1k + 5k strokes every week, is that basically a perpetual thing and no other sharpening is required? (that is apart from thinning which would eventually be required I assume).



It sounds like you have a good idea of what is going on!

Lets say you don't do any thinning: In the beginning your knife will take only a couple of minutes to sharpen on medium to fine stones. Over time your knife will slowly get thicker behind the edge. This does two things, degrades the performance of the knife through foods _and_ makes each subsequent sharpening operation take a longer time. Thinning resets the size of the secondary bevel and fixes these problems. How often you decide to thin is up to you. I do it once every 5 or 6 sharpenings., the Japanese like to do it every time they sharpen and consider it part of the normal sharpening ritual (the _shinogi_ and _urasuki_ on single bevels combine to make thinning quick and easy to do).

Using this method, thinning is the only time I need to use a coarse stone. Doing so keeps the secondary bevel so small that a polishing stone is all that's needed to fix it.

There was a recent thread relating to this topic here: Tiny Bevels and how to create/maintain them.



Boynutman said:


> And do you deliberately raise a burr during these touch ups, or is it just that you know from practice a few strokes will work anyhow so no bothering about this?


It sounds like you've already worked this out. A couple of strokes with a medium stone on a tiny "impossible to see" bevel will make a huge difference, maybe even resetting the entire bevel. An experienced sharpener wont have to look for a burr in this case, but finding one is still a sign that things are progressing well.

Keep in mind these factors will affect the size of the burr:
- Steel type and heat treatment
- Abrasive used and its grit size
- Inclusive angle of the bevels on either side of the edge

It's possible that you might never find one!


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## chinacats (May 28, 2016)

Smurfmacaw said:


> Ok, I'm lazy....perpendicular deburring technique? Link....pretty please :biggrin:



Check out number 17 on Jon's sharpening playlist...stropping and burr removal.


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## spoiledbroth (May 28, 2016)

I don't own a coarser stone than 1k but imo I don't really see the benefit of going lower than 800 on the cutting edge beyond speed. I have been thinning the knife every ~4 weeks on a king 1200 which is actually coarser than the bester 1k according to lee valley

If I am grinding the new edge on 1k / 5k I will usually look quite hard for the burr all the way to the end but during the week just polishing I will sometimes not look for a burr at all.


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## Boynutman (May 28, 2016)

So if you do a few strokes on the 1k and 5k, why the 1k? I am assuming that the few strokes on the 5k are not enough to fully polish the 1k effects? So is this something that will give some toothiness on an otherwise too smooth 5k finish, or is this something that just gives a good edge in practice? 
(Or may be my assumption is incorrect and the few 5k strokes are enough to polish the 1k finish).


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## spoiledbroth (May 29, 2016)

Maybe you are misunderstanding. Once a week I grind a new bevel on 1k. This is not a few strokes this is full on Asian technique grinding the edge in sections and moving the edge up ever so slightly and raising a burr, then refining that edge on 5k. Thereafter throughout the week, as needed, the knife gets a few strokes on the 5k to bring it back to shaving sharpness. Hope this makes sense!


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## Boynutman (May 29, 2016)

Yes, that makes sense. What I am taking away from all of this is that it does take some regular effort to keep the edge sharp. I realize that I am definitely not fully proficient at free hand sharpening yet (still not consistently achieving shaving sharp on my 5k stone), but I now also understand that some light maintenance in between full sharpenings is to be expected. All of the above has been really useful for me to get some perspective.

Thanks everybody!


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## LifeByA1000Cuts (May 29, 2016)

I use a J3000/J8000 as a main (sometimes with an Erdblatt as a post-finisher. And I also consider myself still a beginner), and I try not to go higher from the J3000 side unless at least leg hair is shaved (after making sure there is no noticeable burr). Actually, it sometimes happens that I do something stupid on the polishing side and *lose* that property temporarily... It seems the Wusthoff J8000 is comparatively aggressive, it CAN raise a burr again if you're patient (and bothering to do so actually gave good results wrt edge retention).


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## rick alen (Jun 4, 2016)

I find that [email protected]/R2 steel requires better than a 6K to really show what it's got. A unique property of these steels I have found that with less than a 10K finish they will somehow snag and pull at fibers in paper towel and tissue. I've never done any tests but I would think any significant toothiness here would just chip off. I get great performance and better edge retention with the high grits. But then again I like the high grits even for German stainless. What can I say, it works for me.


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## LifeByA1000Cuts (Jun 5, 2016)

From current experience, I find that using newspaper on a table to strop seems underrated - gets stuff back to shaving that otherwise would have needed a ceramic rod...


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## masibu (Jun 13, 2016)

rick alen said:


> I find that [email protected]/R2 steel requires better than a 6K to really show what it's got. A unique property of these steels I have found that with less than a 10K finish they will somehow snag and pull at fibers in paper towel and tissue. I've never done any tests but I would think any significant toothiness here would just chip off. I get great performance and better edge retention with the high grits. But then again I like the high grits even for German stainless. What can I say, it works for me.



I have been taking all my knives to an ss2k finish lately for comparisons sake and found absolutely nothing wrong with it on sg2. probably wouldn't shave my face with it but it could be done I guess. Germans I would micro bevel at ~1k (was using an ss800 with a light splash with good results) but sharpen very little of them anymore as I managed to convince people to invest in Japanese knives for work. 

carbon steel seems to benefit from higher grit finishes and lower angles depending how thin the blade is closer to the edge (finishing maybe 20 degrees inclusive for thinner grinds but I freehand so who knows). sk4 has been getting finished on the 2k ss and responds well to stropping on this stone when dry. White, v2 and blue can go beyond the snow white they end up being finished on but im trying to limit the number of stones I have laying around work and have been enjoying my results enough coming from ss 400, ss 2000 and the snow white. The 2000 has been my main touch up stone the past few months and does a good job finishing carbon slicers and and the ever so common vg10 gyutos that pop up. The ss400 is not as coarse as it would seem but does a good enough job removing smaller chips. It also happens to leave a cosmetically appealing finish on clad blades after thinning (which has been getting done with either a crystolon or shapton pro 220.. clad blades and softer stainless see the norton where solid blades see the shapton). The ss2000 doesn't scratch up this finish either. 

regardless of whether I finish on the 2000 or 8000, the blade Im sharpening will generally shave arm hair off the stone if I've done a decent job of it. More importantly, there will be a decent level of bite on my thumbnail/pen and no noticeable burr. I don't really have any tests although dicing onion seems to be a good indicator whether my knife has been thinned sufficiently/evenly. There should be minimal resistance cutting with the tip.


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## LucasFur (Jun 16, 2016)

Not that it matters but o have to disagree R2 does shave quite well when you have it right. i use a 10k chosera - chromOX and ironOX - I know this because I shave test almost all my knives. BUT i have a better experience shaving with the classic carbons, almost always, R2 being the best *stainless* knife shaver I have used. I think i deleted my takamura shave but here is a teruyasu denka AS 210 -https://www.youtube.com/watch?v=u8bQf0SnCVI - excuse the girlfriends comments haha.


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## Keith Sinclair (Jun 17, 2016)

Use newspaper to take off any residual burr, less is best. Slice through a sheet of newspaper to test sharpness. Less sound sharper blade also feeling of no resistance. I'm with Masibu dicing an onion horizontal slices good to test tip sharpness.


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## Benuser (Jun 17, 2016)

Boynutman said:


> The UX10 is still not fully what I had hoped for and I am thinking that too comes down to sharpening skill and not the knife itself.


The UX-10 is a bit a special case: as it's coarsely grained, I wouldn't go too far with polishing. I use higher grits only for stropping and deburring. But above all you should be aware that its factory edge is overly convexed and weakened by the buffering. Start on the right side with a coarse stone behind the edge at the lowest possible angle until you raise a burr to make sure the factory edge has gone. I would aim for an asymmetric edge, right face convexed ending at some 12 degree, left side an almost imperceptible bevel of some 20 degree. Verify for steering.


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## Boynutman (Jun 18, 2016)

So how does the steel's coarse grain and the grit size interact? Does this influence sharpness or edge longevity?
I finished sharpening by making a micro bevel. What grid would you use for this?

During sharpening I pretty much kept the angles like above, I verified and adjusted steering by cutting carrot planks. Learned the hard way by screwing up in an earlier sharpening session... but it does make a big difference in ease of cutting once the steering is gone!


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## Matus (Jun 18, 2016)

I usually sharpen my knives when I notice that they would not want to bite into tomato skin. That is the case at the moment as I am not finding the time to sharpen the herd. And I really should.


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## LifeByA1000Cuts (Jun 18, 2016)

Get something kataba, they steer only half as much, and only in one direction...


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## Benuser (Jun 18, 2016)

Boynutman said:


> So how does the steel's coarse grain and the grit size interact? Does this influence sharpness or edge longevity?
> I finished sharpening by making a micro bevel. What grid would you use for this?


I would say I prefer to enhance an existing quality rather than fighting against it. So, with a coarse grain, I don't go beyond 2k except for deburring. With a finer grain I may look for a highly polished edge. As for the micro-bevel, traditionally it is being made with the highest stone. With the UX-10 I could imagine excellent results on the 2k or 3k though.


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## Benuser (Jun 19, 2016)

Please be aware you can't expect the same edge retention with a 180mm gyuto as with a 240 or 270 one.


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## psfred (Jun 19, 2016)

Here's the deal with carbide size and shape: Carbides are very hard, almost as hard as the aluminum oxide in synthetic stones and close in hardness (if not harder) than the silicone dioxide in natural stones. When sharpening, typically one does not actually abrade the carbide particles unless using diamond stones, you are actually removing the material around the carbides to form the edge. 

Very fine carbides are much smaller than the grit in the sharpening stone, so you can polish the edge to a fine apex without issue. Coarse carbides, particularly the chromium carbides in stainless steels, are much larger and big enough that they cannot be removed along with the matrix of iron. Since they are hard enough that they won't "grind away" much, they end up sticking out of the iron matrix, and polishing an apex at the edge on a steel of that sort usually results in the carbides being pulled out of the matrix, leaving an apex of soft iron alloy that looks like swiss cheese. Needless to say, it cannot stay sharp long.

If you sharpen only with moderate grit stones, the large carbides stay put, and although you have a more "sawtooth" apex, those carbides, firmly embedded in the steel matrix, resist wear. While the knife will not be classically sharp, it won't dull very fast.

Hence the recommendation to use medium grit stones on knives with large carbides. This is the approach used in classic German stainless knives -- they are tough, very resistant to chipping, and will hold a fairly mediocre edge for a very long time IF you gently steel them to re-align the fairly soft apex regularly. Works OK and the knives can be sharpened very quickly on a belt grinder to a decent edge.

I have found that soft stainless works great if I finish the edge by stropping the edge with chromium oxide on wood after a synthetic aoto, you may want to try that with UX-10. The aoto is a muddy stone, and with light pressure should refine the apex and leave the large carbides in place. The chromium oxide just deburrs the edge and polishes the roughness off the apex, it won't remove the carbides if done lightly. 

Oddly the edge off the aoto on steels like VG-10 is very blah -- won't cut tomato skin, for instance, but progression through a 6K stone and stropping (or 8k, for that matter) produces a nice edge. Go figure....

Peter


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## Boynutman (Jun 19, 2016)

Thanks Benuser and Psfred, very enlightening.

Now I have some understanding of the mechanics behind it, makes it easier to understand what I am doing and why I am doing it. So I have an R2 knife, a UX10, and 2 VG10 knifes. Sounds like they all need a slightly different treatment to really get out their full potential. From now on I will try to observe more consciously what different progressions achieve.

Thing is, I am cutting way too little to require (or justify) frequent sharpening so for me experience comes pretty slowly. That's why it is so great to have some new input from the forum along the way every now and then!


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## LifeByA1000Cuts (Jun 19, 2016)

I thought carbides not being abraded meant that you use an ill-suited stone, and that this was the reason for stones being classified "low alloy steel"/"high alloy steel"?


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## spoiledbroth (Jun 20, 2016)

so much thinking...

but there is only to do....


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## gic (Jun 20, 2016)

I found what Psfred said amazingly interesting, thanks!

ZKnives said this: "In addition, an objective of the forging process is to end up with a finer-grained steel. So both steel choice,and the way that steel is handled, can effect cutting performance." 

So I guess there isn't a way to know the size of the carbides in a given steel without destructive testing?


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## Kippington (Jun 20, 2016)

You wont need destructive testing if you have tools for metallography/microscopy.

You seem to be talking about two separate things: '*Grain size*' and '*Carbides*'. Anything without carbon wont have carbides. For example a sample of pure metal can have grains, but no carbides. Carbon steel and stainless steel knives will have carbides _between_ the grains of steel. The shape and size of both of these are affected by the choice of steel and the heat treatment of the sample.

You can see clearly in this picture the white carbide bubbles forming along the grey lines of the grain boundaries.







_Fine grain structure at 1000x showing uniform dispersal of carbides. Sample was austenitized at 2240°F and triple tempered at 1025°F to a hardness of HRC 70. _


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## Benuser (Jun 20, 2016)

You may feel on the stones.


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## LifeByA1000Cuts (Jun 20, 2016)

I guess something that requires you to polish up a patch of the steel flat and microscope-ready would be considered destructive testing even if it doesn't make the whole steel object unusable..

No idea what you can or cannot do with X-rays...


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## malexthekid (Jun 20, 2016)

Kippington said:


> You wont need destructive testing if you have tools for metallography/microscopy.
> 
> You seem to be talking about two separate things: '*Grain size*' and '*Carbides*'. Anything without carbon wont have carbides. For example a sample of pure metal can have grains, but no carbides. Carbon steel and stainless steel knives will have carbides _between_ the grains of steel. The shape and size of both of these are affected by the choice of steel and the heat treatment of the sample.
> 
> ...



Thanks for that. I was going to say i thought the carbides, or at least in their smallest size, is a fixed size dependant on their composition.


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## panda (Jun 20, 2016)

i keep my knives 'cut food good' sharp, not frigging shave paper/hair.


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## fujiyama (Jun 22, 2016)

If it's sharp enough to butcher a hooker, I'm happy. Wait.. what?

I meant if it's sharp enough to julienne a green pepper skin side up. I swear.


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## joshsy81 (Jun 23, 2016)

panda said:


> i keep my knives 'cut food good' sharp, not frigging shave paper/hair.



Amen brother, I keep my knives as sharp as I need them to be if that makes sense. Each knife may be a bit different kind of sharp. I pretty much only sharpen at work unless I'm on vacation. I sharpen fast and only to what I need it to be. If it doesn't cut the way I need it to I either deal or if I have time I strop it out. For the most part I would call my edges toothy fine.


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