"Thinning behind the edge"?

[K-Fed]

Yall are so sensitive.

K-fed, I used to re-"geometrize" AND sharpen all of my house knives (5x 10" dexters) but all the cooks abuse the crap out of them and I no longer maintain them, lol. It's a wasted effort.

+3. We now have a "sharpening service". That exchanges crap for crap.... Caught the guy eyeballing my kit and propmtly stashed em' in the office.

 

[Keith Sinclair]

House knives don't work.If you own your own blade & your job depends on fast efficient cutting,most professionals take pretty good care of their knives.You have to, 4 or 5 banquet sheets hanging up on a weekend you better have a knife that works.

For the price the steel in a fibrox forschner is decent.Like most all European knives a V bevel is ground on the edge.Hrt in mid 50's that wide V dulls quickly.When I got my first thin Masamoto,my Forchners collected dust wt. exception of a boning & steamship round carving blade.

I ordered many of the reccom. blades on this forum.Sold them all mostly to students & couple cooks in the field.Put a really sharp edge on a Gesshin Uraku,guy I sold it to loves it.Yesterday sold last one a custom black ash burl handle carbonext to a student,used the same wood for my Dave spa treated Hiromoto AS.The thinning job on it was so good,I let them cut vegitables with it,but it is a keeper that I like to show off

 

[K-Fed]

Just sold my glestain to a "sous chef" at work. Just tired of what I would call sub standard steel and ht.

 

[Salty dog]

Um, I'm still confused.

I googled it.... http://answers.yahoo.com/question/index?qid=20100623094845AAd1MN0

 

[knyfeknerd]

sandy mangina

 

[jaybett]

Thinning is removing metal from the knife to increase performance without hitting the edge, period. Thinner knives cut better as long as they aren't flat ground, and are thick enough to withstand whatever their intended use is. Thinning is always good unless your knife chips or deforms near the edge under normal use. I've bought and seen quite a number of knives off of the BST. As far as I can tell, very few people know what appropriate thinning is and really don't do it at all even when they think they are. As for sharpening twice per week, to each their own. I like my edges sharp. If I were a pro cutting stuff all day, I'd probably be sharpening every day and after spending a lot of time touching up on 5k stones, I have to say that a couple of passes on a 400 grit stone before your 5k touch-up, does wonders. You should try it NO CHOP.

I'm just trying to learn and understand, not get into a debate.

There is probably an exception, but would it be fair to say, that sharpening without thinning creates an edge that doesn't match up with the geometry of the knife? The picture ER took of the Kramer, has a tiny v shaped edge, that isn't in alignment with the grind of the knife.

I'd be curious to know what are the common mistakes that people are making when they are thinning their knives? I'm probably making the same mistakes.

Jay

 

[jaybett]

i bet your knives don't cut well. i'm entirely able to believe they are keen. these are different things. "sharpening" is a small part of the equation. go look at what a good sushi chef does to his deba and yanagiba, and then ask him why.

I don't know if I have made your list? If you can see this, I believe you are talking about having a knife that's edge would pass common tests for sharpness, but would have issues cutting. When you say a knife a knife doesn't cut well, are we talking about wedging, dragging, or something else?

Jay

 

[tk59]

...sharpening without thinning creates an edge that doesn't match up with the geometry of the knife? The picture ER took of the Kramer, has a tiny v shaped edge, that isn't in alignment with the grind of the knife...

In general, I'd say the ideal geometry of a knife is whatever you happen to like NOT including that v shaped edge. That's the part that doesn't fit but it's useful because it gives the edge strength. Without thinning, that little (and relatively thick) edge takes over the overall geometry of the knife, making it closer to the geometry of an ax than a tool for cutting food. That little v should always be minimized. This is the idea with microbevels, too. You sharpen the knife the way you want it to cut but find the edge is too thin to withstand use so you make the edge thicker which is very bad for cutting but since it's tiny, it does not contribute significantly to the overall geometry of the knife.

...the common mistakes that people are making when they are thinning their knives?...

By far the most common mistake is not removing enough metal. I've seen knives bought that were supposedly thinned many times over years of use with the original grind marks from the manufacturer near the edge bevels. If you're thinning correctly, most of those grind marks will be gone after one or two thinning sessions barring low spots on the grind.

After that, there's thinning too much (this is rare), not thinning both sides appropriately, taking too much off the softer cladding vs the harder, more wear resistant core, rounding shoulders, I'm sure there's more and variations depending on the type of grind.

 

[TheDispossessed]

just FYI, my gyuto which hits the 400 grit weekly is 9 months old and has lost 1mm height at the heel.
you can use a low grit stone with finesse.
and just being a long time forum member or pro cook does not make your knowledge and skills infallible.

 

[TheDispossessed]

Not to be disrespectful, but a purveyor of cutlery telling one that it's OK to put your knife on a 400 grit stone several times a week, is like McDonalds telling you a BigMac is healthy.

I hope you're not referring to Jon here, if you are it is majorly disrespectful in my opinion. This is someone who has trained extensively in Japan with some of the country's best sharpeners and does this for a living. He freely gives out advice be it through phone calls, emails or youtube videos to people, most of whom probably never buy a damn thing from him. The Japanese are very protective of their skills and craft, and to have someone translate and share this knowledge is an immense resource for all of us.

 

[NO ChoP!]

just FYI, my gyuto which hits the 400 grit weekly is 9 months old and has lost 1mm height at the heel.
you can use a low grit stone with finesse.
and just being a long time forum member or pro cook does not make your knowledge and skills infallible.

To me 1mm in 9 months is a bunch, especially for knives meant to last a lifetime. So in 5 years you'll have lost almost 7mm? Your gyuto would be short even for a suji at that point....

This is my point exactly. Just because I try to make my knives last doesn't mean I don't know how to sharpen, and the implication is just plain rude. Spending $400, or more on a knife is a very substantial investment for me, and I try to baby my knives as much as possible. I clean my Nike Air Max everytime I wear them, too.

I truly didn't mean anything disrespectful towards Jon, and I can clearly see it came off that way. My apologies.

I do still stand by my statement that not trying to make your edges last, and resorting to frequent low grit sharpening is not necessary. I do understand that many are true knuts and just enjoy the practice, but for me I enjoy spending time to get my knife as perfectly tuned as possible, and then seeing how long I can make that edge last in a hardcore environment.

 

[NO ChoP!]

And I'm going to throw something else out there, and try to be as careful as possible to not offend anyone.

I think the main difference we are witnessing here is two different types of users. Being that I work in a kitchen, I use my knives for a living. The current job I hold actually has me with a knife in-hand for a good part of the day. My joy of knives is in using them daily, as a tool of the trade, something I rely on.

On the flip side, you have guys who simply enjoy nice knives. They use them occasionally in a home environment, maybe to make some awesome dinners. Their joy probably comes from handling them. Sharpening, polishing, tuning; so when they do use them, they are friggin' machines....probably just as or more knutty than the pro. I get it.

But, I think we need to coincide and respect one another.

 

[Salty dog]

The basis of my confusion is my perception of a knife that needs to be thinned behind the edge. An example would be any of the "house" knives in my kitchen. They've been sharpened on a Tru-Hone machine or at too steep of angles. The edge begins to resemble the spine. I just have never purchased a quality knife where any edge thinning is needed. To this day I have never consciously "thinned the edge" on any of my knives? Even the pudgy Mizuno honyakis. Hence my confusion.

I rarely use my 400, I don't spend much time on the stones and I sharpen at a pretty shallow angle. (Or is it steep? You know what I mean)

I don't have a theory on this but this has been my experience.

 

[Lefty]

And I'm going to throw something else out there, and try to be as careful as possible to not offend anyone.

I think the main difference we are witnessing here is two different types of users. Being that I work in a kitchen, I use my knives for a living. The current job I hold actually has me with a knife in-hand for a good part of the day. My joy of knives is in using them daily, as a tool of the trade, something I rely on.

On the flip side, you have guys who simply enjoy nice knives. They use them occasionally in a home environment, maybe to make some awesome dinners. Their joy probably comes from handling them. Sharpening, polishing, tuning; so when they do use them, they are friggin' machines....probably just as or more knutty than the pro. I get it.

But, I think we need to coincide and respect one another.

You're 100% right. I'm essentially a home user, so I could get all up in arms, but the truth of the matter is, pros use these and get the satisfaction from knowing that one of their most important tools is always going to come through for them, while making their job a bit more personal. For a home user, it's all in babying and taking care of your prize knife - be that sharpening, polishing, oiling, etc.

Of course, a large part of my job is cooking, despite the fact that I consider myself a home user. The funny thing is, my work knives are the ones that I get the most satisfaction out of using, despite being less glamorous than my "prizes". Interesting....

 

[Craig]

So what exactly is the difference between thinning behind the edge and putting on a microbevel?

 

[EdipisReks]

So what exactly is the difference between thinning behind the edge and putting on a microbevel?

a microbevel thickens an edge.

 

[harlock0083]

So what exactly is the difference between thinning behind the edge and putting on a microbevel?

I don't think those are even related.

On a different note, I don't see a need to put my knife a coarse stone constantly (IMO once you've set the bevel or have done whatever thinning you needed on a coarse stone). I only use a coarse stone for repairs mostly chips and what not.

 

[EdipisReks]

Being that I work in a kitchen, I use my knives for a living. The current job I hold actually has me with a knife in-hand for a good part of the day. My joy of knives is in using them daily, as a tool of the trade, something I rely on.

if you're absolutes were true, there wouldn't be wire thin yanagibas at sushi restaurants.

 

[EdipisReks]

Even the pudgy Mizuno honyakis. Hence my confusion.

I used your pass-around Mizuno. It was a nicely made knife, but it didn't cut as well as it should have, because it was very thick behind the edge. I've handled a newish one, since, and it wasn't that way, close to OOTB. The new one was thick at the spine, but tapered quite abruptly, to a fine edge. I can only assume yours started out that way.

 

[EdipisReks]

I don't think those are even related.

On a different note, I don't see a need to put my knife a coarse stone constantly (IMO once you've set the bevel or have done whatever thinning you needed on a coarse stone). I only use a coarse stone for repairs mostly chips and what not.

When I thin my knives, which is a regular part of my maintenance, I do it with a Chosera 1000. I only go to a coarser stone when something needs correction. It typically takes 5-10 minutes per side, when part of a routine, and only that long because I like to set up a uniform finish before spending another 2 minutes per side with finger stones, to restore polish.

When I do regular thinning, it is after I have sharpened enough that the primary bevel has thickened the edge to the point where it can be noticed (perhaps every third time I sharpen a knife). Thinning then smooths out the noticeable bevel back into the normal geometry of the knife, and resets the geometry. This does not take long at all, if done regularly, and restores cutting ability. We are not talking about very much removed metal, and almost no removed metal at the edge, which means the knife only slowly reduces in height. Removing lots of metal at the edge is what reduces the height of a knife. This should be self-evident.

My goal, when i get a knife that I really like the performance of, is to keep it cutting as close to the best it can for the life of the knife. Not keeping the geometry in place is, to me, like not regularly changing your car's oil. Maintaining the geometry of the knife regularly extends the life of the knife, not vice verse. A knife that is thin at the edge and has a good geometry needs to be sharpened less often, not more, because the geometry of the blade does much of the cutting work. This is not a regimen that came automatically to me, but instead took time and practice and observation and talking to people more knowledgable than myself. I sharpen my knives a lot less than I used to, and cutting performance stays much higher, because I'm treating my tools correctly.

 

[Salty dog]

I used your pass-around Mizuno. It was a nicely made knife, but it didn't cut as well as it should have, because it was very thick behind the edge. I've handled a newish one, since, and it wasn't that way, close to OOTB. The new one was thick at the spine, but tapered quite abruptly, to a fine edge. I can only assume yours started out that way.

No, it really hasn't seen much use. I think they changed their geometry over time. My blue and white were the first ones made. They weren't exactly what I was looking for at the time (Mighty) but I've come to appreciate them much more.

 

[EdipisReks]

No, it really hasn't seen much use. I think they changed their geometry over time. My blue and white were the first ones made. They weren't exactly what I was looking for at the time (Mighty) but I've come to appreciate them much more.

Then that knife definitely needed some thinning, because the new one I tried cut very well.

 

[jaybett]

In general, I'd say the ideal geometry of a knife is whatever you happen to like NOT including that v shaped edge. That's the part that doesn't fit but it's useful because it gives the edge strength. Without thinning, that little (and relatively thick) edge takes over the overall geometry of the knife, making it closer to the geometry of an ax than a tool for cutting food. That little v should always be minimized. This is the idea with microbevels, too. You sharpen the knife the way you want it to cut but find the edge is too thin to withstand use so you make the edge thicker which is very bad for cutting but since it's tiny, it does not contribute significantly to the overall geometry of the knife.



By far the most common mistake is not removing enough metal. I've seen knives bought that were supposedly thinned many times over years of use with the original grind marks from the manufacturer near the edge bevels. If you're thinning correctly, most of those grind marks will be gone after one or two thinning sessions barring low spots on the grind.

After that, there's thinning too much (this is rare), not thinning both sides appropriately, taking too much off the softer cladding vs the harder, more wear resistant core, rounding shoulders, I'm sure there's more and variations depending on the type of grind.

Thanks for the information.

Jay

 

[panda]

i agree with edipis. over the course of trying to get various knives to perform, i've found every knife became better 'cutters' after essentially regrinding the bottom portion of the blade. even when the cutting edge is not so keen, because the shape of the blade constitutes good performance, it will still be serviceable.

for example, even though i don't maintain the house knives any more, they still cut WAY better than they were stock with a keen edge.

i'll put it this way, given the choice between two identical knives but in different conditions:

A) brand new knife, no thinning, newly formed very sharp edge
B) well used knife, heavily thinned, but dulled edge

i would pick knife B every time.

 

[harlock0083]

i agree with edipis. over the course of trying to get various knives to perform, i've found every knife became better 'cutters' after essentially regrinding the bottom portion of the blade. even when the cutting edge is not so keen, because the shape of the blade constitutes good performance, it will still be serviceable.

for example, even though i don't maintain the house knives any more, they still cut WAY better than they were stock with a keen edge.

i'll put it this way, given the choice between two identical knives but in different conditions:

A) brand new knife, no thinning, newly formed very sharp edge
B) well used knife, heavily thinned, but dulled edge

i would pick knife B every time.

A thin and dull knife is still dull. You'd be using more force than necessary for cutting. I'd pick A given the two choices myself. C would be to sharpen the thin dulll knife.....

 

[EdipisReks]

A thin and dull knife is still dull. You'd be using more force than necessary for cutting. I'd pick A given the two choices myself. C would be to sharpen the thin dulll knife.....

Depends on what you are cutting. A very thin at the edge, but dull, knife will still sink into potatoes in a way a keen, but fat, knife never will. Of course, thin and keen is much better, for most cutting tasks.

 

[harlock0083]

Depends on what you are cutting. A very thin at the edge, but dull, knife will still sink into potatoes in a way a keen, but fat, knife never will. Of course, thin and keen is much better, for most cutting tasks.

Point taken, the thin knife feels "usefully sharp/dull". I can understand the why people want super thin/ultra sharp edge, but there seems to be an over obsession for keeping one's knife razor sharp 24/7 (at one point I was in this camp, homecooks also have it easier in terms of maintenance, but now I just maintain the edge until I feel the need to put it on a medium stone).

As a side note, giving a two year old a plastic butter knife and a potato will occupy him long enough to cook dinner.

 

[EdipisReks]

A lot of it depends on what your uses are. I keep going back to the sushi example, but if you have to cut very thin and precise portions of protein a lot, you'll be keeping your knife geometry and keenness very high at all times. If all you do is prep mirepoix for stock, it's less necessary. Most use cases are in between, of course.

 

[Keith Sinclair]

A thin and dull knife is still dull. You'd be using more force than necessary for cutting. I'd pick A given the two choices myself. C would be to sharpen the thin dulll knife.....

JMO vastly prefer thin ground knives for most cutting duties.They are also easier to touch up.Spine doesn't have to be real thin,but down the blade face as common on many quality J-Gyuto.Thinning is one of those terms that may have different meanings.My first bevel is close to the stone(I call it back bevel)Depending how assemetric determines how high the polish line on blade road.The backside polish is higher than cutting side on highly assem. knives.Using this loosely but say 2mm on front & 3mm backside.So its not thinning up the sides of the blade,it is more as Edipis said maintaining good edge geometry.(Final bevel) is twice the height off the stone which makes a type of blended convex edge that glides thu food.

I would keep a worn thin carbon gyuto that only had one shallow close to the stone bevel on both sides.No final bevel.Good for cutting Maki Rolls & inside out sushi rolls.We served alot of Nori Panko crusted Ahi,any crusted protien wt. a damp towel on the board to wipe the blade.

I am sure No Chop knows what works for him to keep his blades going.I used cleavers alot too & would put diff bevels on cheap chinese carbon cleavers would use a wider bevel for lobster splitting blade than thin for chopping herbs & vegitables.

There are diff. ways to get a blade sharp.Bottom line is if it works for you that's what matters.

 

[Salty dog]

@ No Chop, all ad-hominisms aside...........they will never understand.