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mateo
11-30-2011, 02:26 AM
I've been sharpening now for about 2.5 years as a home cook... and I feel my edges are getting better all the time. I can make a very sharp edge, I'm currently hunting for retention (I can make a nice sharp edge, but it's "gone" after 2-4 cutting sessions -- as in noticeably deteriorates, it's still sharp by most people standards).

Beyond that, though, I've been having an issue. My knives can easily shave hair but won't fall through a tomato. No matter what condition they're in -- if I just finished a sharpening session, they won't and if it's been a month or so, they just sit right on top and laugh at me, but they can still shave. What's going on here? Anyone have a bloody clue? It also doesn't matter which knife I'm using.

jm2hill
11-30-2011, 03:40 AM
I'll take a ponder and firstly ask, why knives are you using? I'd imagine if it wasn't thin behind the edge its not going to fall through a tomato!

JohnnyChance
11-30-2011, 05:45 AM
What is your sharpening process? What stone do you finish on? Do you strop, if so, on what? What knives/steels are you using?

tk59
11-30-2011, 03:29 PM
Two things are particularly important here: bevel angles and the alignment of the teeth on your edge. You need low angles and very light stropping and you'll be fine, as long as you're just kissing the edge.

Eamon Burke
11-30-2011, 03:42 PM
Yeah, we need mas informacion. Knives you are using, the sharpening progression and your cutting board.

tk59
11-30-2011, 04:08 PM
I was talking about the tomato part. I forgot the edge retention part. That is more complicated.

stevenStefano
11-30-2011, 04:17 PM
Sounds intriguing. If the blade was slipping off the tomato that would be an easy fix but if it won't cut it well that's different. Perhaps you're sharpening at too high an angle? Guess we won't know until you give a little more info

bprescot
11-30-2011, 04:46 PM
I think the OP means this:
http://www.youtube.com/watch?v=BA5AzvQW8lg

Peco
11-30-2011, 04:52 PM
Can someone please explain why they need knifes that sharp? I just sharpened my knife using 1000 grit, 5000 grit and raw leather as stropping. Result: a very sharp gyuto that worked extremely well in my kitchen.

deanb
11-30-2011, 05:46 PM
Can someone please explain why they need knifes that sharp? I just sharpened my knife using 1000 grit, 5000 grit and raw leather as stropping. Result: a very sharp gyuto that worked extremely well in my kitchen.
It's the difference between "need" and "want". I want to have knives that sharp. I like to sharpen and the tomato test is a good one.

Peco
11-30-2011, 06:08 PM
It's the difference between "need" and "want". I want to have knives that sharp. I like to sharpen and the tomato test is a good one.

Well you can do the tomato test, slicing thin without gripping it - with a 5K finish + stropping. I just wonder how fragile the edge is when thinning that much? I just received a knife sharpened by Carter, edge were maybe 0,5 milimeter in height and it was razor sharp. Just looking at his edge learned me a lot. After some use I took it to the stones and put a tiny edge on the knife ... became razor sharp again. After some use I used a hone and the edge became toothy which worked well cutting both veggies and protein.

Don't get me wrong, I like my knife sharp too. Sometimes I just wonder why one would go thru tons of grits, diamondsprayed strops etc. when you really don't have to. Of course if it's pure interest or hobby I understand, but for everyday use I can't see why one needs to? Am I wrong saying it's almost overkill?

memorael
11-30-2011, 06:27 PM
To the OP, shaving hair is really not hard at all. I know it sounds like I am exaggerating but the truth is a cinder block and cardboard will take an edge to shaving sharp. If you want to shave to see if it is sharp or not I suggest shaving your beard, anything that pulls, or is painful will pretty much not be "sharp" (take this in perspective to what we are used to around here). Tomatoes on the other hand have a retarded skin that is actually super tough and even more retarded, in my experience, is full grown artichoke skin NOW THAT IS A TEST THERE.

To Peco, you would be amazed at what a ultra sharp knife edge can do in the right hands, forget about brunoise and all that other mambo jambo, I know of someone who's knife was sharpest out of all the ones I have seen (it literally fell through stuff with absolutely no pressure). On the other hand you are thinking well yeah that edge probably lasted one second, and so did I till he was done with all the cutting and the edge was still pristine. Extremely surreal if you ask me, but what was even more surreal was all the cuts he did, they were all perfect, the sides of carrots seemed velvety smooth. So I guess some people do "need" not want an edge that is ultra fine.

Peco
11-30-2011, 06:37 PM
To Peco, you would be amazed at what a ultra sharp knife edge can do in the right hands, forget about brunoise and all that other mambo jambo, I know of someone who's knife was sharpest out of all the ones I have seen (it literally fell through stuff with absolutely no pressure). On the other hand you are thinking well yeah that edge probably lasted one second, and so did I till he was done with all the cutting and the edge was still pristine. Extremely surreal if you ask me, but what was even more surreal was all the cuts he did, they were all perfect, the sides of carrots seemed velvety smooth. So I guess some people do "need" not want an edge that is ultra fine.

That's how I feel when cutting, maybe it's because I made a switch from German knifes :dontknow:

tk59
11-30-2011, 07:04 PM
...Sometimes I just wonder why one would go thru tons of grits, diamondsprayed strops etc. when you really don't have to...I have some ultrafine compounds. They are useless. I use 1k to resharpen, a min on 5k, a few strokes on 8k and a few strokes on a strop with 1 micron diamond and I can pass all the sharpness tests. I can go months without resharpening if I had to so it isn't that fragile.

stevenStefano
11-30-2011, 07:12 PM
Don't get me wrong, I like my knife sharp too. Sometimes I just wonder why one would go thru tons of grits, diamondsprayed strops etc. when you really don't have to. Of course if it's pure interest or hobby I understand, but for everyday use I can't see why one needs to? Am I wrong saying it's almost overkill?

I think I agree. I know knives and sharpening is a hobby for many people, but I think there is a point of diminishing returns when it comes to sharpening. After I sharpen I spend maybe 5 mins stropping on 0.5 chromium on felt. I don't see the point in going much further than that with incredibly fine compounds, I think the time it takes to use them and notice a difference is better spent doing other things

Cadillac J
11-30-2011, 07:29 PM
I have some ultrafine compounds. They are useless. I use 1k to resharpen, a min on 5k, a few strokes on 8k and a few strokes on a strop with 1 micron diamond and I can pass all the sharpness tests. I can go months without resharpening if I had to so it isn't that fragile.

This. All I use is a 600-1K-5K and usually 1micron strop(or not), and it is all anyone will ever need for double-bevels without any compromise in sharpness/cutting capabilities.

mateo
12-01-2011, 12:07 AM
Sorry guys! Working today...

My usual progression is 1200/8k combo King stone, finish on 0.5 micron diamond on leather strop. I have a Bester 700 that I don't use all the much. Sharpening depends on the knife. My most recent acquisition is a Konosuke Chuka in White #2. This blade I did a rather time consuming multi-stage edge (like single bevel... only I can't think of the word right now) with two different angles on the bevel grind, then a micro-bevel at about 30-35* (I can check this more accurately if needed); for the micro-bevel I went with a visual evaluation on this -- I was recommended that this bevel should be able the width of a hair, so I increased my angle until I hit that width.

Second main knife is my Yoshikane gyuto, SKD tool steel core. This has about a 30/70 (right hand bias -- so 30% is on the left, 70% on the right) blade grind, and what I've found I like is reversing the edge grind to a 70/30; making the bevel much wider on the right side of the knife... which is contrary to the norm, but I find the edge is really nice then... except, of course, on tomatoes. No micro bevel. If I had to guess angles I say left bevel is about 20-25* and the right about 10.

Third is a Takagi nakiri in Blue #2. This knife is hard to sharpen... I haven't honestly been that impressed with my edges. Of all the blade I thought would drop through tomatoes, this one, to me is the most surprising it doesn't. This has about a 40/60 (left/right) bevel grind, with a 15* or so edge bevel. I actually tried to grind the knife like I do the Chuka with a two-stage bevel grind and a very small micro-bevel, but good lord this steel is HARD.

That's what I'm rolling with... I guess what I'm looking for are suggestions here. I know the steel/knives can do it, that's not the question. This is 100% user error... I just am not sure what that error is? Wire edge? Burrs? Not actually forming a proper edge? I'd be happy to post photos, videos, etc.

tk59
12-01-2011, 12:13 AM
I don't get the 70/30 thing. All of my edges have a large bevel on the right side and I'm right handed. Have you tried going without the leather strop? What happens to your edge retention then? When you notice your edge isn't cutting great, can you see light reflecting off the edge when it's pointed right at you?

As for the tomato thing, 25 deg is WAY too big. Go to 15 deg. It isn't wire edge/burr either because one can pass the tomato test with a wire edge, no problem.

allumirati
12-01-2011, 01:01 AM
1st thing is to find the right angle for the knife. Usually I'll try to go as thin as I can go, then I have problems with it, then I put a micro-bevel that is to high and becomes to big over time so it's very sharp but not scary sharp. So then next step is to go a step down from there. Which is medium angle usually about 15* per side. I also like asymetric sharpening but that gets a bit more complicated for me (if I'm trying to make a DURABLE edge). I like to play with different angles a lot at this point and I'm always changing my methods but medium angles are a good place to start.

2nd thing. I know this is contrary to instinct and to 99.9% others' advice but...use as much pressure as possible. This will ensure you're removing the weak metal and actually sharpening the metal you're going to be cutting with, not the metal you're going to be removing later.

3rd thing either don't polish too much (more than 4k-6k) or get a natural stone which most of the time give you highly polished but "bitey" edges.

4th thing if doing a symetrical grind you can count down (alternating sides) strokes for instance I use 3,2,1, 1/2. 1/2 meaning only grinding from heel to tip or tip to heel, 1 meaning both ways. If you do single strokes you can start with a higher number. Of course that takes more time then which some of us don't have much. Obviously if you want asymetrical you can switch numbers like 6-4, 7-3, etc. Basically you want to make sure you're using each stone to it's full potential by making sure you're refining the edge to it's max on that particular stone.

Good luck :P

allumirati
12-01-2011, 01:06 AM
Forgot another thing...if you want to thin the edge try not to go all the way to the edge when sharpening at extremely low angles otherwise you'll weaken the edge. I know it's tempting to get the lowest possible angle on a knife. But an ultra acute edge that's rolled is way worse than a crisp medium angled edge.

JohnnyChance
12-01-2011, 02:03 AM
...the sides of carrots seemed velvety smooth.

This is my favorite thing about wicked sharp edges.

memorael
12-01-2011, 05:35 PM
Its sexy isn't it when the carrot doesn't bleed and the mouth feel is all crunchy and velvety.

bikehunter
12-01-2011, 06:01 PM
..... and even more retarded, in my experience, is full grown artichoke skin NOW THAT IS A TEST THERE.


In my experience, prepping artichokes is very close to the ultimate, edge holding stress test for any kitchen knife. <G>

heirkb
12-01-2011, 07:55 PM
...When you notice your edge isn't cutting great, can you see light reflecting off the edge when it's pointed right at you?...

What would it mean if one were to see this? That one has a wire edge that has rolled? I've seen this on segments of my edges before, but I'm pretty sure that was because of me stupidly banging the edge on something.

tk59
12-02-2011, 12:27 AM
...use as much pressure as possible. This will ensure you're removing the weak metal and actually sharpening the metal you're going to be cutting with, not the metal you're going to be removing later...The only thing tons of pressure assures you of is making a more concave edge. If that's what you want, fine. In smaller bevels and thinner blade geometries, the edge will be weaker but thinner very close to the edge and thickening up dramatically as you reach the shoulder on your bevel. If you go lighter, you can drop your angle and get the same edge strength. If you want to be assured you are removing all the weak metal, you just need to make sure you have a significant burr at some point OR you can make a microbevel OR you can do a 90 deg deburr, etc. That part has absolutely nothing at all to do with pressure.

tk59
12-02-2011, 12:30 AM
What would it mean if one were to see this? That one has a wire edge that has rolled? I've seen this on segments of my edges before, but I'm pretty sure that was because of me stupidly banging the edge on something.Some people say they can get through a complete shift on a wire edge. To me that's really just a thin, weak edge. To me, a wire edge is one that folds over after one tomato slice or so. If substantial parts of the edge have rolled over after one slice, it's a wire edge. If it takes a lot of slices then maybe the edge is just a bit thin and I would have recommended thickening up or decreasing pressure or putting a micro on, etc.

heirkb
12-02-2011, 01:25 AM
Thanks for the response. I guess it was me accidentally banging the edge, then.

allumirati
12-02-2011, 02:49 AM
The only thing tons of pressure assures you of is making a more concave edge. If that's what you want, fine. In smaller bevels and thinner blade geometries, the edge will be weaker but thinner very close to the edge and thickening up dramatically as you reach the shoulder on your bevel. If you go lighter, you can drop your angle and get the same edge strength. If you want to be assured you are removing all the weak metal, you just need to make sure you have a significant burr at some point OR you can make a microbevel OR you can do a 90 deg deburr, etc. That part has absolutely nothing at all to do with pressure.


I knew nobody was going to agree with me on this, but take it for what you will. I just know that when I sharpen this way my edges last longer and I put them through a lot 6 days a week and I don't have to hit anything below 8 or 4k a day for a week. And when I do I don't really have to I just like thinning. Anyways it's not about getting rid of the metal that you can see coming off, it's about removing the metal that you used to make thousands of cuts during the week so it makes clean hundreds of cuts a night and almost everything I cut is tougher than tomatoes. And the whole thing about bringing a burr on each stone makes sense in theory, but in practice if you don't use enough pressure you're only flipping the burr that was created by the first stone rather than pushing it off into the stone so the stone can go to work on the edge below that. So your left with a nice shiny uber sharp wire edge. And no amount of "deburring" after this point is going to leave you with as clean an edge as you could have.

memorael
12-02-2011, 05:37 AM
I knew nobody was going to agree with me on this, but take it for what you will. I just know that when I sharpen this way my edges last longer and I put them through a lot 6 days a week and I don't have to hit anything below 8 or 4k a day for a week. And when I do I don't really have to I just like thinning. Anyways it's not about getting rid of the metal that you can see coming off, it's about removing the metal that you used to make thousands of cuts during the week so it makes clean hundreds of cuts a night and almost everything I cut is tougher than tomatoes. And the whole thing about bringing a burr on each stone makes sense in theory, but in practice if you don't use enough pressure you're only flipping the burr that was created by the first stone rather than pushing it off into the stone so the stone can go to work on the edge below that. So your left with a nice shiny uber sharp wire edge. And no amount of "deburring" after this point is going to leave you with as clean an edge as you could have.

This is completely false. Saying you put a lot of pressure doesn't really mean anything concrete. Anyway if you put a LOT of pressure you will create mini grantons on a very small scale on every finger that you put pressure on. This will create a weak edge and at the end of the day all you get is a week edge. Also 4k and 8k are two very different stones so I get a bit confused on this too. If you get over a whole week with little to no work on your knife kudos, I am just sure it isn't because of your explanation, something else is at work there.

Cadillac J
12-02-2011, 05:40 PM
I do agree that you have to make sure you removed all the fatigued metal in order to have edge longevity, but you don't need extreme pressure to do this...just have to make sure you spend a bit more time grinding after you first feel the burr form.

Everyone here that is a good sharpener has their own way of doing things--we might not all agree with each other on specifics, but if you are getting results that make you happy, good for you.

Citizen Snips
12-03-2011, 01:17 AM
i have to say that shaving and tomato are different tests.

shaving edge will not fall through a tomato and tomato test will not be the best at shaving. for me, its like comparing apples and oranges. i try to get an edge that will slice tomatoes well and feel really sharp with a three finger test while still having the ability to shave arm hair.

the key is getting all this and having edge retention. to me all this together make for really good sharpening techniques

allumirati
12-03-2011, 02:44 AM
This is completely false. Saying you put a lot of pressure doesn't really mean anything concrete. Anyway if you put a LOT of pressure you will create mini grantons on a very small scale on every finger that you put pressure on. This will create a weak edge and at the end of the day all you get is a week edge. Also 4k and 8k are two very different stones so I get a bit confused on this too. If you get over a whole week with little to no work on your knife kudos, I am just sure it isn't because of your explanation, something else is at work there.

If using a lot of pressure doesn't work for you, don't do it. Just don't tell me I'm wrong when it works for me. I never said that my method was the only way. It's just I get what I want out of this method and I've tried just about everything in the book. I work 6 days a week so I don't have time to leisurely sharpen I just need my edges in peak condition fast.

mini gratons? that's why you keep moving the edge on the stone.

Personally I think shaving and tomato tests don't prove anything, you could say the same for paper. That is if the knife was made for cooking which can involve making beautiful slices of delicate fish or pounding through hundreds of pounds of veggies. And for most of us we use the same knife for both tasks. So yeah...

memorael
12-03-2011, 03:58 AM
If using a lot of pressure doesn't work for you, don't do it. Just don't tell me I'm wrong when it works for me. I never said that my method was the only way. It's just I get what I want out of this method and I've tried just about everything in the book. I work 6 days a week so I don't have time to leisurely sharpen I just need my edges in peak condition fast.

mini gratons? that's why you keep moving the edge on the stone.

Personally I think shaving and tomato tests don't prove anything, you could say the same for paper. That is if the knife was made for cooking which can involve making beautiful slices of delicate fish or pounding through hundreds of pounds of veggies. And for most of us we use the same knife for both tasks. So yeah...

If you put a LOT of pressure (which in context is really not specific at all) which I consider a lot something that will bend the steel behind every finger that is applying pressure you WILL get mini indentations on the knife. Whatever it is you are doing it isn't working because of a lot of pressure that is the end of the story like it or not.

Citizen Snips
12-03-2011, 08:19 AM
If you put a LOT of pressure (which in context is really not specific at all) which I consider a lot something that will bend the steel behind every finger that is applying pressure you WILL get mini indentations on the knife. Whatever it is you are doing it isn't working because of a lot of pressure that is the end of the story like it or not.

im not sure i agree with this. i personally dont use a lot of pressure but there are lots of people out there that believe that putting lots of pressure is essential. as far as the indentations go, is that not something you can polish out??

@alluirati: the shaving and tomato tests are not just some made up tests that people like to chat about. i use them to judge what my edge is going to act like in a high volume environment and not as any way to prove something. they can be very useful and if you dont find them useful, thats fine. im curious if you have a test or just put it to work. also, i dont think many people use their gyuto to slice fish...just sayin.

stevenStefano
12-03-2011, 11:41 AM
If you want to know about high pressure sharpening, I think kcma on Foodie Forums is an expert in that. I always remember he said he sharpened with big pressure and he really knows his stuff if anyone that has ever posted there can testify. Maybe post on Foodie Forums about it? Any time I use pressure I just screw up the profile of the knife, with the indentations that have been mentioned. If you get one near the sweep at the tip you're screwed

memorael
12-03-2011, 01:38 PM
If you want to know about high pressure sharpening, I think kcma on Foodie Forums is an expert in that. I always remember he said he sharpened with big pressure and he really knows his stuff if anyone that has ever posted there can testify. Maybe post on Foodie Forums about it? Any time I use pressure I just screw up the profile of the knife, with the indentations that have been mentioned. If you get one near the sweep at the tip you're screwed

I have seen KCMA sharpen his knife and the dude does put a lot of pressure and he also does about 200 miles per hour on the freaking stone, the deal with him is he sharpens at such a low angle (literally about 1 degree it seems the knife is flat against the stone) that the pressure he puts acts in a different way since the knife flexs on a whole different plane. Truth is there isn't a single way to sharpen knives, Dave has mentioned he likes seeing how knives come with distinct sharpening fingerprints from their owners.

The mini indentations or Grantons that kinda form usually turn into the S shaped or M shaped edges and happens when sharpening at higher angles and especially on knives that flex a lot, the Kikuichi TKC knife comes to mind, that knife flex's a bit (at least in my case). And they can be sharpened out but at a very high cost which is lots of steel. Like the saying goes, many roads lead to Rome, or there's more than one way to skin a cat. We could get into this and spend several hours if not days and conclude that usually high pressure on knives and stones is not something desirable, I would say that enough pressure to create a nice grinding even grinding noise is enough, it should sound melodic. Any change in the noise and your probably grinding more metal on one particular spot.

allumirati
12-03-2011, 03:54 PM
im not sure i agree with this. i personally dont use a lot of pressure but there are lots of people out there that believe that putting lots of pressure is essential. as far as the indentations go, is that not something you can polish out??

@alluirati: the shaving and tomato tests are not just some made up tests that people like to chat about. i use them to judge what my edge is going to act like in a high volume environment and not as any way to prove something. they can be very useful and if you dont find them useful, thats fine. im curious if you have a test or just put it to work. also, i dont think many people use their gyuto to slice fish...just sayin.

If you put pressure in one place for too long then you get those overground spots, or if your stone is not flat. Classic examples are birds beak tips and dips near the heel. This is not a matter of pressure it's a matter of bad technique and stone maintainence.

I'm not saying I don't test my edges with shaving, tomato, or paper. Just saying different edges work better for different purposes.

For example I like a bitey"er" edge for maki that won't necessarily shave well or cut paper SMOOTHLY. But if the edge is too smooth sometimes it doesn't perform well on maki. Specifically ones with the seaweed outside.

AND I reserve my yanagi for slicing fish or softer rolls that can be squished easily like spicy tuna. For that I like my edges polished as high as possible which usually shaves and slices paper well.

But I've been experimenting with my cheapo chinese 12k and I like these edges for slicing sticky salmon. And kind of gives me good edges for maki too. Eventually I might get a nicer natural stone.

And yes I've developed my technique with pointers from KCMA although I don't always sharpen this way. And really if you figure out how to do it this way it really is faster.

tk59
12-03-2011, 05:45 PM
I have seen KCMA sharpen his knife and the dude does put a lot of pressure and he also does about 200 miles per hour on the freaking stone, the deal with him is he sharpens at such a low angle (literally about 1 degree it seems the knife is flat against the stone) that the pressure he puts acts in a different way since the knife flexs on a whole different plane...He would be making a concave edge and the metal behind the edge would be weak as a result. Depending on how much deformation is happening, it might only be suitable for very careful, light duty work.

Citizen Snips
12-03-2011, 07:32 PM
If you put pressure in one place for too long then you get those overground spots, or if your stone is not flat. Classic examples are birds beak tips and dips near the heel. This is not a matter of pressure it's a matter of bad technique and stone maintainence.

I'm not saying I don't test my edges with shaving, tomato, or paper. Just saying different edges work better for different purposes.

For example I like a bitey"er" edge for maki that won't necessarily shave well or cut paper SMOOTHLY. But if the edge is too smooth sometimes it doesn't perform well on maki. Specifically ones with the seaweed outside.

AND I reserve my yanagi for slicing fish or softer rolls that can be squished easily like spicy tuna. For that I like my edges polished as high as possible which usually shaves and slices paper well.

But I've been experimenting with my cheapo chinese 12k and I like these edges for slicing sticky salmon. And kind of gives me good edges for maki too. Eventually I might get a nicer natural stone.

And yes I've developed my technique with pointers from KCMA although I don't always sharpen this way. And really if you figure out how to do it this way it really is faster.

what you are saying is all true. there are many different edges that do many different tasks. the key is to find what works for you for a specific knife for a specific task. if it works for multiple tasks and keeps its edge a long time, those are bonuses. i certainly do not finish my yanagi and gyuto on the same stone.

i know kc and understand what he does and why the way he is, it is just different than me. i do use a good amount of pressure, but nothing like him. if he was able, he would put his entire body weight on the tips of his fingers for sharpening. i like a bit more refined pressure and when you put THAT much pressure, you tend to lose control which is, in my opinion, the most important part of sharpening.

mateo
12-04-2011, 01:41 AM
i have to say that shaving and tomato are different tests.

shaving edge will not fall through a tomato and tomato test will not be the best at shaving. for me, its like comparing apples and oranges. i try to get an edge that will slice tomatoes well and feel really sharp with a three finger test while still having the ability to shave arm hair.

the key is getting all this and having edge retention. to me all this together make for really good sharpening techniques

hmmm... well, I think I'm going to hit the stones this weekend at some point, so I'll see what happens! Thanks for the advice guys.