A "toothy" problem.

So, you've heard it before - my knife is sharp but won't cut tomatoes. I work in a kitchen where we portion a lot of veg during service so I experience this problem daily and I've had enough! [emoji51].

My regular routine is a NANIWA pro 800 - NANIWA pro 3k - NANIWA 5k. Currently, I only take 1 knife to 5k and leave the rest at 3k as I feel that at 5k there is zero bite in my edge (both using the fingernail test and through practical usage). While I understand that refining an edge removes toothyness I have seen videos of people going to 10 or 12k and horizontally push cutting tomatoes. My problem occurs on a variety of steels including w2, b2, 01, 52100 and vg10.

I believe that my technique on the stones is a world away from perfect but I'm achieving results more than adequate for other cutting tasks. I'm pretty sure I'm deburring adequately (too much possibly?!) using end grain wood and my angles, while less consistent than a pro, are pretty "normal".

My question - is there a way of maintaining a toothy edge at higher grits? I very much enjoy the greater level of perceived sharpness for prep tasks but simply can't take a knife higher than 3k without wanting to launch it when I go to dice a pepper!

Thanks guys!!

My first guess would be the sharpening technique (5k stone should normally give you edge with enough bite for tomatoes). If your sharpening angle wobbles too much, than you may be 'rounding over' the cutting edge. Do you get an edge you want with 3k - or is that one too toothy? Are you creating burr with 5k?

Just to make sure - did you check the sharpening videos from Jon Broida of JKI?

[video=youtube;GB3jkRi1dKs]https://www.youtube.com/watch?v=GB3jkRi1dKs&list=PLEBF55079F53216AB[/video]

@Matus

Thanks for the reply! Like I say, I think I'm achieving a sharp edge at 5k just not necessarily a toothy one. For example, an onion at 5k feels great but a tomato using my 5k edge is miserable [emoji24] 3k is fine in as much as I can make a large item into smaller items but it just doesn't feel as effortless as it could. I have been aiming for a burr at 5k but it's possible that my fingers are telling me there's one there when there isn't?? Also yes - Jon's videos were the perfect intro to proper technique. I shall re watch and analyse to make sure I'm not doing anything dumb!

Your 800 leaves already quite a refined edge with a 1200-like pattern. Only reason for using higher grits is in deburring -- inevitably on the 800 some of the burr remains. I would suggest to use the 3k only for stropping and deburring, and the 5k for very light deburring only.

@Benuser So the takeaway from this is that my technique is lacking. Now I know where to start. I believe I understand the concept of stopping in that it weakens and lessens a burred edge however when you refer to deburring, do you mean a lateral, horizontal stroke across the stone? (As demonstrated in Jon Broida's videos?).

practice practice practice, don't even go past your 800 stone. instead strop on cardboard after you have done your sharpening. if it isnt cleanly cutting items, start over. rinse and repeat until you get it right. it will take many tries but you'll get there eventually. this is one of those skills that just takes massive amounts of repetition and muscle memory to get good at. people that have been doing this for years still arent very good at it because they never developed good technique perhaps because they just werent taught right, or are thinking they are doing it right when theyre really not. hell my technique is probably lacking too to be honest.

King_Bickfast said:

@Benuser So the takeaway from this is that my technique is lacking. Now I know where to start. I believe I understand the concept of stopping in that it weakens and lessens a burred edge however when you refer to deburring, do you mean a lateral, horizontal stroke across the stone? (As demonstrated in Jon Broida's videos?).

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Yes, indeed, about stropping and deburring. As for the 5k, it isn't easy to see the benefit you may take from it after the 3k, besides a very last cleaning up. With other Naniwa Pro you really feel what happens with the burr. No so much with the 5k I'm afraid

Benuser - it seems to me like I may have been putting too much work in on the higher grit stones and over refining my edge. When I next get the chance, I'm going to take this information back to the stones and I'll report back asap. Thanks all!!

Are you able to cut tomatoes easily even just right after sharpening on the finer grits, not accounting for edge wear due to usage? If not, I'm inclined to think it's a sharpening technique inconsistency - deburring incompletely or rounding the edge. Fine grit stones are less forgiving of angle holding inconsistencies has been my experience. But tomato cutting with a recently sharpened 6-8k synth edge should be achievable...

I use my Akifusas for tomatoes. They are sharpened Naniwa Chosera (essentially same as Pro) 1k, then Naniwa Junpaku 8k and they slay tomatoes. I am certainly not an expert sharpener but I do deburr very carefully after each stone.

Nemo said:

I use my Akifusas for tomatoes. They are sharpened Naniwa Chosera (essentially same as Pro) 1k, then Naniwa Junpaku 8k and they slay tomatoes. I am certainly not an expert sharpener but I do deburr very carefully after each stone.

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My experience is the same, 8000 snow white definitely leaves you with enough teeth for tomato.

"my knife is sharp but won't cut tomatoes"

Curious: How does a sponge react to the edge - how easily does it slice, and is there a chance of purely pushing into it (if there is, we have a true case of damn-sharp-but-too-smooth. Most knives that will do a tomato won't. A fresh razor blade will.)? Can you pure-push into a newspaper edge held a cm or two away from where you are trying to cut?

Is the problem with whole tomatoes, or laid-flat quarters skin-up (which I found can be a challenge to edges that will easily cut a whole tomato)?

I know everyone is coming at you with every possible solution and in that sense I'm adding to the sharpening soup here but it reflects my experience such as it is. I found this technique hugely helped with my grabbiness into smooth-skinned items at higher grits. But then it also vastly improved my edges at lower grits too.

https://youtu.be/qhs7d5rANdY

@muchobocho did an incredible post that turned me into this if you can find it

Use pressure only on the edge trailing pass. This helps to maintain the teeth along the edge you've been working hard to make.

It's also important to check your work during sharpening. You don't want to spend a lot of time to find out at the end the edge isn't "toothy". With dry hands check to see if there is a burr. I touch the edge with my finger tips to check how toothy the edge is. I also lightly run my finger tip perpendicular to the edge with short strokes.

Wonder what the catch would be with giving an overpolished edge a few light strokes on something coarser (probably going one sided, differential grit)?

Just my experience use pressure edge trailing. Or lift the blade as in Badgers vid. I would try just sharpening on a 1K stone for tomato's. Would dice at least one 25# case of tomato's at a time for Lomi Salmon. Masamoto carbon on a 1K king stone, lateral stroke for burr removal.

Buy an Aizu

Was this about the Masamoto HC?

Badgertooth said:

Buy an Aizu

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Could you please devellop a bit? Excuse my ignorance.

Well that Cris Anderson Video that Badgertooth posted also helped me improve.. "ok if he is doing this it might work" .. then tried it and i always do those moves and "cutting the water" at the end of every stone.
Also i always pull the knife trough a piece of cork after every stone no matter what grit it has.

Actually 8k is mini overkill, with 4k it should go through tomatoes like a lasersword of doom. Or a 1k and jump to 8k would also give it a great mix of "polished saw".

..."Buy an Aizu"... puh i wish i could marry my Aizu .. (excuse my ignorance).
Buuut... with a 1k +8 setup its more a fun stone in between.. and a good 4k Synth will also do the job... but is boring for me.

Does he count strokes? I work on one side, raise a burr and and start with the other one, again a bit behind the edge.

Benuser said:

Was this about the Masamoto HC?

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All my Masa's were mono virgin carbon steel. 1K toothy edge great for tomato's

So getting a non-tomato-friendly edge from a high grit is not a sign that one's sharpening has gotten worse, but the opposite?

One thing to try someday: Do one microbevel at 400 and a more obtuse one on top of it at 8000 ... Wonder if these side teeth would still bite?

No. Contact will be with the 8k edge. You will encounter a very slight performance loss because of the coarse finish behind it.

With regards to the OP, one of the questions I asked in my first post to this thread was whether this was about lack of bite on tomatoes after some usage (maybe wrong grit choice or even edge/bevel durability), or right after sharpening (more likely technique). I maintain that the 4-8k or so range of fine synthetic stones should not overpolish the edge such that it struggles with tomatoes right after sharpening. At least, it hasn't happened to me yet with an edge I know I didn't do a poor job on.

foody518 said:

With regards to the OP, one of the questions I asked in my first post to this thread was whether this was about lack of bite on tomatoes after some usage (maybe wrong grit choice or even edge/bevel durability), or right after sharpening (more likely technique). I maintain that the 4-8k or so range of fine synthetic stones should not overpolish the edge such that it struggles with tomatoes right after sharpening. At least, it hasn't happened to me yet with an edge I know I didn't do a poor job on.

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Answering this would help us help you.

In my experience in a pro kitchen prepping for several hours a day (especially on poly boards), a refined 6k edge will lose its bite after a day or two, making tomatoes a royal PITA. To combat this, I keep a stainless 150 or 210 petty or gyuto around that is a 1k edge (and maybe a quick stropping on a fine stone to make sure the burr is gone). VG10 knives work just fine for this. When prepping tomatoes and the edge starts to struggle, a couple passes on a fine rod (idahone ~1k in my case) will bring back the bite. This is the sole reason I keep a rod with me. I also often use these knives to break down raw meat.

Cheers,
rj

@Benuser will tomato skin not be compliant around the edge at that scale if there is any pressure at all? I thought that was what makes the skin on tomatoes, plums and people so hard to push cut....

Did you get better results?

Hi all!

I'm incredibly sorry to have let this thread die (only to be recently resurrected) - work got crazy and i lost a lot of time to that.

TLDR; I got to the bottom of it.

As i previously mentioned, a lower grit edge was fine for items with skin and it was only the jump to a 5k stone that caused a series of minor tomato-related meltdowns. A fresh edge off 5k would carve sponge and briefly pierce tomato skin however half way through service the same day be dull. I believe this was due to poor deburring technique and, to a lesser extent, over refining of the edge. The remedy to this was as simple as demurring laterally and to finish at lower grits. I've since received an aoto from Mr.Watanabe which creates a VERY toothy and pleasant edge. I'm now very satisfied with the performance of all my blades for every task, Including the once-dreaded case of plum vines!


Cheers kkf!