"Thinning behind the edge"?

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Let me try this again... I posted it in the wrong thread earlier...



+1 to Jon's vid's.

I posted this one of Murray Carter a short time ago in another thread, but it's worth posting again here. The title refers to sharpening convex bevels, and it include a lesson on thinning.

[video=youtube;UdEe9sEQRcE]http://www.youtube.com/watch?v=UdEe9sEQRcE[/video]

If you don't want to watch the whole thing, skip to about 5:30 where he does a nice illustrated explanation of thinning - as he calls it - the secondary edge. 'Round here we call it the secondary bevel, or if it doesn't have a true secondary bevel, behind the edge.
 
Metal removal is metal removal, and weekly thinning on a 400 grit is excessive. You aren't thinning two parallel sides. And the more you thin, the more thinning you will need to do, as you move up the blade and it becomes thicker and thicker. 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.

To all the lurkers and newer members, I think the point to make is, learn to sharpen so that your edges last as long as possible, stretching them out with touch ups and stropping is preferred. 1000 grit is usual low enough to remove tired metal. Fine tuning is essential, and keeping your edge thin is good, but planting this mindset that it should be a biweekly routine is nonsense.

If ones bevel has deteriorated so greatly in a few days time to where a brand new bevel must be reset (sub 1000 grit), and thinning behind the edge is necessary, I'd like to see the use of this knife in action. I am a chef in a country club, I break down literal cases of meat, poultry, fish and vegetables on plastic boards and am able to keep my edges for weeks.
 
Word Chris!

NO ChoP! said:
To all the lurkers and newer members, I think the point to make is, learn to sharpen so that your edges last as long as possible, stretching them out with touch ups and stropping is preferred. 1000 grit is usual low enough to remove tired metal. Fine tuning is essential, and keeping your edge thin is good, but planting this mindset that it should be a biweekly routine is nonsense.
Click to expand...
 
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.
 
JBroida said:
I don't know guys.... It really could be ok depending on how he sharpens... I have knives I've thinned at least once a week and they are still around after almost 8 years. Just because you're thinning doesn't mean you have to be removing a ton of metal... It could be just a bit each time... Just enough to keep the knife right where you want it geometry-wise
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in my experience, i remove much less vertical material when i'm aggressively thinning knives. that makes a knife last a lot longer.
 
NO ChoP! said:
I'm still a firm believer that many are too quick to remove a bunch of metal. Why thin and sharpen so frequently? Does ones knife really need a full progression starting all the way down to low grit full thinning every week? I like to try and do as little metal removal as possible, increasing my knifes longevity. I do agree that some knives need a bit of tuning, and thinning is all part of upkeep; that being said, I only resort to a full progression when my actual bevel has deteriorated, which takes a ton of abuse to achieve. Usually touch ups will get me through for a very, very long time.
Click to expand...

the point of thinning is to maintain geometry. if you maintain geometry, you're going to be removing a lot less height from the knife every time you sharpen, compared to if you just go at the edge every time. yanagibas and usubas get thinned every time they are sharpened. this is good practice for double bevel knives, too, especially with knives like Heiji where it is expedited by the way the blade is shaped. not thinning often means the blade becomes thick, and then you have to remove a ton of steel all at once. knives have to be thinned to maintain good cutting performance. simply sharpening the edge does very little to maintain cutting performance.

a lot of people have knives that they think cut well when they are, in fact, merely keen. i've handled an awful lot of those, from people on this forum.
 
NO ChoP! said:
Metal removal is metal removal, and weekly thinning on a 400 grit is excessive. You aren't thinning two parallel sides. And the more you thin, the more thinning you will need to do, as you move up the blade and it becomes thicker and thicker. 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.

To all the lurkers and newer members, I think the point to make is, learn to sharpen so that your edges last as long as possible, stretching them out with touch ups and stropping is preferred. 1000 grit is usual low enough to remove tired metal. Fine tuning is essential, and keeping your edge thin is good, but planting this mindset that it should be a biweekly routine is nonsense.

If ones bevel has deteriorated so greatly in a few days time to where a brand new bevel must be reset (sub 1000 grit), and thinning behind the edge is necessary, I'd like to see the use of this knife in action. I am a chef in a country club, I break down literal cases of meat, poultry, fish and vegetables on plastic boards and am able to keep my edges for weeks.
Click to expand...

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.
 
one last post on this thread: if you buy a very good double bevel knife, you'll almost always find that is has a very thin tip. if you want to keep this very thin tip, you have to thin the knife regularly. sharpening without thinning ruins tips, and very quickly, and thinning occasionally almost always ruins the tip, because the geometry of the knife gets away from you if you only thin every once in a while. this isn't rocket science. it's also much easier to sharpen a knife that is thin at the edge, vs. one that has become a hatchet.
 
gic said:
Thining all the way up the knife or just truly behind the edge??
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one last post: thinning is a misnomer. "maintaining the geometry" is a much better way to put it.
 
Really? I tried...I really tried.

Who are you clowns to question my sharpening abilities? I've been around this block just as long as the both of you. I've handled, owned and used many great knives. It figures that the two most arrogant members here would try to trash talk me. I've been a pro; you know, someone who gets paid for his knife skills for decades. I will go out on a limb and challenge anyone to any skill, any time. Yes, I am that confident. I don't just sit around in my sweater vest and sharpen knives under a microscope; I actually use them, as they were intended. Telling me I don't know how to maintain my prized possessions goes beyond arrogant, it borders arrogant stupidity. Thanks for the lesson on how and why to thin, I'm glad you decided my stance on people going to the stones too frequently meant I mustn't know how to use them. I stand by my statement that biweekly thinning and sharpening seems excessive, even for a pro. Not all of us were born into wealth.
 
pathetic. i'm an IT person at a public university whose wife is unemployed. i was born into a pretty good position, but i have no wealth. go screw yourself. your ad-hominem post is exactly what somebody who doesn't know crap would post. welcome to my ignore list.
 
Coming from someone who has garnered a reputation as a bully and often resorts to personal attacks. Sure thing, buddy; try again, wrong guy!
 
I can't see your posts, now, and I'm unwilling to hit that "view post" link, but I bet you complain about me calling out homophobes, and then show that you don't know what "ad hominem" means.

[video=youtube;fQbRyay_ojY]http://www.youtube.com/watch?v=fQbRyay_ojY[/video]
 
Yes sir.

My apologies to the innocent bystanders. Sometimes you've gotta take a stand, though....
 
The reason I push J-Gyuto's is many have a taper grind that is thin to begin with.So thinning behind the edge easy done on a 1200 Bester,kick in final bevel on same stone makes for a very functional edge.I thin alot of fiberox handle forschners,the knife of choice at our culinary school.Getting rid of that V grind that it comes with & putting on a compound bevel makes them cut much better.
 
keithsaltydog said:
The reason I push J-Gyuto's is many have a taper grind that is thin to begin with.So thinning behind the edge easy done on a 1200 Bester,kick in final bevel on same stone makes for a very functional edge.I thin alot of fiberox handle forschners,the knife of choice at our culinary school.Getting rid of that V grind that it comes with & putting on a compound bevel makes them cut much better.
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Agreed about the forshners. The chef used to pay me to come in on my off days and take care of the "house" knives. All forshners. Hated doing it, even if it was ot simply because of how they were abused.
 
I usually give Forschner's to my friends if they want a cheap knife, so I wouldn't mind knowing what you do to them. All I do is put a 15 degree primary angle and a 20 degree micro bevel to make them last longer for them I don't thin up the blade but sinc eI am learnign how to use stones, I could start doing that if it really helps them.....
 
gic said:
I usually give Forschner's to my friends if they want a cheap knife, so I wouldn't mind knowing what you do to them. All I do is put a 15 degree primary angle and a 20 degree micro bevel to make them last longer for them I don't thin up the blade but sinc eI am learnign how to use stones, I could start doing that if it really helps them.....
Click to expand...

+1. kfed, starting a thread on how you sharpen forschners is a good idea. i could use some tips.
 
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.
 
+2, I think such a thread would be great, after all if all one has to spend is $30, what knife could possibly be better than a Forschner?? (well except those Tramontina Shun clones but that is a set and runs around $80 on ebay now...)
 
I think there's a couple of different concepts being collapsed here - thinning vs sharpening the secondary bevel.

To me, thinning behind the edge refers to what you would do to a new knife that isn't thin behind the the edge to increase it's cutting performance. The KS that was bought f/ Rakuten showed the thinning process. Once the desired thinness is achieved, it may not be necessary to thin at every sharpening session, but eventually the edge will become think if only the primary bevel is sharpened.

On traditional single bevels knives as well as double bevel knives with a wide compound bevel such as Heiji, the process isn't called thinning - it's simply sharpening. Sharpening is done on the secondary bevel as well as the primary bevel to - as mentioned above - maintain the geometry of the knife.

And I agree w/ ER's post above about thin tips. Additionally, I find thinning/sharpening the 2nd bevel at the tip the most difficult part due tot he curvature of the tip. It's difficult to maintain the proper angle to sharpen only the 2nd bevel and not hit the edge, or over rotate and sharpen above the shinogi, all the while not damaging a thin tip.

I have a couple of double bevel knives without wide bevels - not Heiji - that I have been practicing thinning/sharpening the 2nd bevel on. I've put quote a bit of time into thinning them, and they cut better and better as my sharpening skills get better.
 
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