Expected edge retention/how to tell you're sharpening correctly

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iimi

iimi

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Corpus Christi, TX
I don't think I have an issue getting my knives sharp. I can get most of the knives in my bag to split a hair with a few minutes on the stones. But after one service, the edge isn't biting into my nail like it would right off the stones. Now, this would indicate that I'm not deburring correctly and I'm leaving a wire edge on, but the knife is sharp enough to cut paper towel. Within a few strokes on a stone, I can get that same knife to bite into my nail again, but again, after one longish service, it'll glide on the nail. Overripe cherry tomatoes also start to take a little bit of effort to cut, as I have to make sure I pull cut more than usual. The knife will hold this kind of edge for a few days at a minimum, depending on which knife it is, and it's perfectly useable on every product. It can get a little annoying on super fine bell pepper skin curls and stuff like that, but that's 80% technique anyways. Long winded explanation concluding, is there a way short of buying a digital microscope and inspecting my edges to check if I'm deburring correctly, or is this normal edge retention for the average line cook?
 
Just a.quick side note, I have a ginsan knife that's held a really sharp edge for a couple of prep jobs, and I mean biting nail, cutting tissue paper sharp. AS, white #2, vg10, aus10, ps60 all have not held up as well.
 
Other issues maybe, over stropping, finishing stone as to high of a grit, foil edge or your angle is getting to low. There are so many variables but from what you have said it also my just be your steel type although your white #2 should hold up pretty well.
 
Ive started doing a couple cuts into the cutting board after I'm done sharpening. Then I'll see if the edge has bite from heel to tip. If not, I had some burr left that folded over or tore off a weak edge. Back to the stone, I can often correct it pretty quickly. A nice way to get practical feedback.
 
captaincaed said:
Ive started doing a couple cuts into the cutting board after I'm done sharpening. Then I'll see if the edge has bite from heel to tip. If not, I had some burr left that folded over or tore off a weak edge. Back to the stone, I can often correct it pretty quickly. A nice way to get practical feedback.
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I've tried deburring with high angle edge leading strokes, pulling through edge grain wood, parallel strokes with the burr down, etc. I can get the edge to keep biting after a few cuts, just not after a full shift.
 
What kind of knife is involved, what steel, what board material? Don't expect a softer carbon to keep its fresh from the stones sharpness after half a shift on a poly board.
 
Benuser said:
What kind of knife is involved, what steel, what board material? Don't expect a softer carbon to keep its fresh from the stones sharpness after half a shift on a poly board.
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Yoshimi Kato AS is my most used knife, poly boards, a good amount of acidic foods cut like pineapple or even just a few pounds of onion. Again, I'm not sure if I'm not deburring correctly or if this is the expected level of sharpeness that most chefs use as a working edge. I can shave and all, but I'm just wondering if the failure to bite into my nail means I'm not deburring correctly.
 
Just a wild guess: the bevel's geometry may have to do with it. If it is strongly convexed it won't bite if kept straight. See how it cuts the finest cigarette paper. Whether it's a smooth, possibly silent cut.
 
Brakedeezbohnz said:
I've tried deburring with high angle edge leading strokes, pulling through edge grain wood, parallel strokes with the burr down, etc. I can get the edge to keep biting after a few cuts, just not after a full shift.
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I use this for razors - it’s not the highest magnification, but should start to give you an idea. Gotta use it at home at the computer, but it stays still, has good lighting, easy to adjust, plug and play, not too expensive.
https://www.amazon.com/dp/B07DQM237K?psc=1&ref=ppx_yo2ov_dt_b_product_details
For the knife itself, AS steel is carbon, and pretty brittle, honestly. Sometimes it’s treated a little tougher, but on average, low toughness means it’ll not wear well on a hard poly board. If you have acidic foods, those teeth will degrade pretty quickly, even if the edge is still thin enough for produce like onions and cucumbers.

I’m all for continuing to learn to sharpen and deburr very well, especially at LOW angles. That’ll help keep it feeling sharper, longer. But if you can’t quite seem to find the right combinations of stone, knife and technique, in the short-term, it may be worth considering a simple stainless like Ginsan 3, AUS-8 or AUS-10. They’re all pretty available for solid working-price knives, hold up to abrasion and acid better than carbon steel. Just cuz super is in the name of the steel doesn’t mean it is always so. I’ve had a handful of AS knives over the years, and would only expect one or two to make it through a shift. (I cook at home now, but briefly worked in restaurants a looong time ago, so I’m ball-parking).
 
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captaincaed said:
I use this for razors - it’s not the highest magnification, but should start to give you an idea. Gotta use it at home at the computer, but it stays still, has good lighting, easy to adjust, plug and play, not too expensive.
https://www.amazon.com/dp/B07DQM237K?psc=1&ref=ppx_yo2ov_dt_b_product_details
For the knife itself, AS steel is carbon, and pretty brittle, honestly. Sometimes it’s treated a little tougher, but on average, low toughness means it’ll not wear well on a hard poly board. If you have acidic foods, those teeth will degrade pretty quickly, even if the edge is still thin enough for produce like onions and cucumbers.

I’m all for continuing to learn to sharpen and deburr very well, especially at LOW angles. That’ll help keep it feeling sharper, longer. But if you can’t quite seem to find the right combinations of stone, knife and technique, in the short-term, it may be worth considering a simple stainless like Ginsan 3, AUS-8 or AUS-10. They’re all pretty available for solid working-price knives, hold up to abrasion and acid better than carbon steel. Just cuz super is in the name of the steel doesn’t mean it is always so. I’ve had a handful of AS knives over the years, and would only expect one or two to make it through a shift. (I cook at home now, but briefly worked in restaurants a looong time ago, so I’m ball-parking).
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I do have an AUS-10 and a ginsan that hold up pretty well, but even they don't hold the teeth for more that a couple of shifts at most.
 
You probably aren't doing anything wrong. If you are really banging through bushels of produce at a time then you should expect touchups every couple of shifts at a minimum. There might be some super steels out there combined with some kind of jig or something that will produce scientifically better edges. Otherwise, thin edges and hard steel plus solid cutting technique to stretch the usefulness out when the edge starts to deteriorate is about the best you can do. Get the knife as thin as you can for the job at hand. Thinner behind the edge geometry feels sharper longer. Keep thinning until you see damage from regular use and then back off. Toughen it up with a small micro bevel. Once the geometry is perfect, practice doing touchups with as little metal removal as possible. Only a couple strokes at the beginning or ending of a shift or every couple of shifts to refresh the very apex/microbevel/cutting edge.

I've never used anything to look at the edge for knives or razors. But what you are describing for performance would not be atypical for someone who has a reasonable grasp of the fundamentals. From here all you can really hope for is incremental improvements. Visual inspection improvements may or may not help. But don't neglect your other senses too. Listen to how the different knives sound as your sharpening, how they feel on the stone. A fine ceramic honing rod with a light touch can be very useful for maintenance. I also like having pocket sized naturals for quick touchups. Soft Arkansas is cheap and readily available. A little coticule or aizu is even better if you can swing it. I find that the medium to medium fine grit naturals can refresh an apex quick without much need for further deburring.
 
stringer said:
You probably aren't doing anything wrong. If you are really banging through bushels of produce at a time then you should expect touchups every couple of shifts at a minimum. There might be some super steels out there combined with some kind of jig or something that will produce scientifically better edges. Otherwise, thin edges and hard steel plus solid cutting technique to stretch the usefulness out when the edge starts to deteriorate is about the best you can do. Get the knife as thin as you can for the job at hand. Thinner behind the edge geometry feels sharper longer. Keep thinning until you see damage from regular use and then back off. Toughen it up with a small micro bevel. Once the geometry is perfect, practice doing touchups with as little metal removal as possible. Only a couple strokes at the beginning or ending of a shift or every couple of shifts to refresh the very apex/microbevel/cutting edge.

I've never used anything to look at the edge for knives or razors. But what you are describing for performance would not be atypical for someone who has a reasonable grasp of the fundamentals. From here all you can really hope for is incremental improvements. Visual inspection improvements may or may not help. But don't neglect your other senses too. Listen to how the different knives sound as your sharpening, how they feel on the stone. A fine ceramic honing rod with a light touch can be very useful for maintenance. I also like having pocket sized naturals for quick touchups. Soft Arkansas is cheap and readily available. A little coticule or aizu is even better if you can swing it. I find that the medium to medium fine grit naturals can refresh an apex quick without much need for further deburring.
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When you touch up, you're never deburring, correct? And now that I think about it, I think the large amount of herb chopping and chiffonades is also probably a big contributor to my edges not lasting more than a few days at a time. Thanks for the help, btw, I kinda have no reference to this anywhere around me because none of my coworkers really care much about sharpness or knife maintenance.
 
stringer said:
You probably aren't doing anything wrong. If you are really banging through bushels of produce at a time then you should expect touchups every couple of shifts at a minimum. There might be some super steels out there combined with some kind of jig or something that will produce scientifically better edges. Otherwise, thin edges and hard steel plus solid cutting technique to stretch the usefulness out when the edge starts to deteriorate is about the best you can do. Get the knife as thin as you can for the job at hand. Thinner behind the edge geometry feels sharper longer. Keep thinning until you see damage from regular use and then back off. Toughen it up with a small micro bevel. Once the geometry is perfect, practice doing touchups with as little metal removal as possible. Only a couple strokes at the beginning or ending of a shift or every couple of shifts to refresh the very apex/microbevel/cutting edge.

I've never used anything to look at the edge for knives or razors. But what you are describing for performance would not be atypical for someone who has a reasonable grasp of the fundamentals. From here all you can really hope for is incremental improvements. Visual inspection improvements may or may not help. But don't neglect your other senses too. Listen to how the different knives sound as your sharpening, how they feel on the stone. A fine ceramic honing rod with a light touch can be very useful for maintenance. I also like having pocket sized naturals for quick touchups. Soft Arkansas is cheap and readily available. A little coticule or aizu is even better if you can swing it. I find that the medium to medium fine grit naturals can refresh an apex quick without much need for further deburring.
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Agree with all of this. I’ve used Yoshimi Kato AS at work and it holds up well, but still needed a touch up every couple of shifts.

What stone/grit are you finishing on? Getting an edge that cuts tissue paper is impressive, but an edge like that usually won’t hold long under hard use. I’ve found anything over about 3000 grit loses bite fairly quickly if you’re banging on hard poly boards.
 
Brakedeezbohnz said:
When you touch up, you're never deburring, correct? And now that I think about it, I think the large amount of herb chopping and chiffonades is also probably a big contributor to my edges not lasting more than a few days at a time. Thanks for the help, btw, I kinda have no reference to this anywhere around me because none of my coworkers really care much about sharpness or knife maintenance.
Click to expand...

I am very careful to minimize the burr as much as possible at each step so that there isn't a whole lot of burr development to have to deal with. The goal is to remove as little metal as possible to have the greatest impact on edge sharpness and retention. Time and metal are money. The more metal you remove and the bigger burrs you are building the faster your knife shrinks and the more time you spend sharpening. Knife nirvana is having a bunch of tools that are all dialed in and you have to buy projects to have something to sharpen. Touchups should be quick and not need much deburring. You want to extend the amount of time you need between cutting fresh bevels. Repeatedly cutting fresh bevels will make the knife thick and burn through sharpening stones and metal when you are sharpening multiple times per week. A knife that is dialed in nice can last through dozens of touchups without needing extended maintenance work. But if you get it too thin then you have to fix damage more often and that eats steel too. So like with everything is all about balancing the competing forces and practicing until you get better.
 
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When I cut lots of acidic food, I use something stainless or semi-stainless. Like Z-wear sharpened on diamond stones 😎 (diamond stones aren't necessary but makes life easier).
 
Brakedeezbohnz said:
When you touch up, you're never deburring, correct?
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When touching up I actually do exactly the same as when deburring. A few edge leading strokes on Belgian Blue, followed by a few strokes along the edge. True, that first edge leading strokes hardly raise a burr: that's the nature of the stone.
 
Benuser said:
When touching up I actually do exactly the same as when deburring. A few edge leading strokes on Belgian Blue, followed by a few strokes along the edge. True, that first edge leading strokes hardly raise a burr: that's the nature of the stone.
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That's pretty much what I do with my cerax 3k.
 
Moving thread to Sharpening Station forum.
 
Benuser said:
I don't know the stone. The advantage of the BB in this application is in not raising a burr that quickly. Most synthetics do abrade a burr, but raise a new one in the same time.
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Yeah, the BB does seem to do a bit of the burr minimisation for you.
 
Also, I'm happy to say that I seem to have at least somewhat figured out what was causing my edge to lose bite so fast, it was probably the stropping/overdoing the burr removal techniques. Last night I just did a few light edge leading strokes and some parallel passes and finished on some end grain, no stropping or further refinement, and at the end of the day it is still bitey (Kato AS). I put it through a lot of green onion curls, 10# or so of yellow onion slices, 7# of cooked chicken thighs, and a good chunk of my fingernail and index finger tip. Due to the last produce, I can attest that the knife is indeed sharp.
 
Brakedeezbohnz said:
Also, I'm happy to say that I seem to have at least somewhat figured out what was causing my edge to lose bite so fast, it was probably the stropping/overdoing the burr removal techniques. Last night I just did a few light edge leading strokes and some parallel passes and finished on some end grain, no stropping or further refinement, and at the end of the day it is still bitey (Kato AS). I put it through a lot of green onion curls, 10# or so of yellow onion slices, 7# of cooked chicken thighs, and a good chunk of my fingernail and index finger tip. Due to the last produce, I can attest that the knife is indeed sharp.
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Glad you've found a path. I'm going to throw out one more pitfall. I don't know if it's affecting you, because I don't know what stones you're using.

I really like the Shapton Glass stones. They are fast with pressure, and finer than grit without pressure. This last is what can lead to trouble. Even the mid-grit Shapton Glass 1000 can yield an insufficiently-scratchy edge, if I spend too much time on it, doing my usual thing of backing off on the pressure as I go on. Great edge, but no longer toothy.

I've found better luck (with knives, not razors) by finishing on something with some scratch to it. That way, no matter how much time I find I need to spend, no matter how light my pressure gets, I still get a scratchy edge. Some JNats work that way, even suitas of quite fine average grit. But in a more reasonable price range, soft arks, as recommended by Stringer, do this beautifully. I have a Dan's soft ark that does this so well it seems like cheating. My washita performs similarly.
 
Excellent news. Corresponds to what may be expected from well-treated AS. As thin as possible behind the edge, and ending with a more or less conservative edge. That is at least my experience.
Overly stropping is indeed likely to create a new, fresh burr — not just assembling all old debris. I don't find it always simple to make the difference. Perhaps by stropping on the hand palm: as far as I know unlikely to create a new burr, but efficient enough to collect burr remnants.
 
For the chefs/ former chefs:

Lets say you start a shift with unions, are your knives still as sharp at union 20-30 as it was at union 1?
And I really mean that same fresh of the stone/strop?

My reference is less then zero, so I really don't know what to expect from myself on edge retention.

My knives behave like the very opening post, only I cook way less per day (home meal for 2). I thought it was normal to loose that true 100% sharpness rather quickly, but the knive holds like 90% of the sharpeness a very long time.
 
Rangen said:
Glad you've found a path. I'm going to throw out one more pitfall. I don't know if it's affecting you, because I don't know what stones you're using.

I really like the Shapton Glass stones. They are fast with pressure, and finer than grit without pressure. This last is what can lead to trouble. Even the mid-grit Shapton Glass 1000 can yield an insufficiently-scratchy edge, if I spend too much time on it, doing my usual thing of backing off on the pressure as I go on. Great edge, but no longer toothy.

I've found better luck (with knives, not razors) by finishing on something with some scratch to it. That way, no matter how much time I find I need to spend, no matter how light my pressure gets, I still get a scratchy edge. Some JNats work that way, even suitas of quite fine average grit. But in a more reasonable price range, soft arks, as recommended by Stringer, do this beautifully. I have a Dan's soft ark that does this so well it seems like cheating. My washita performs similarly.
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I just so happen to have a Dan's soft ark sitting unused.......
 
BINGO!

Also, cut some paper.

If there is a wire edge etc then the sharpness will drop off very suddenly


M1k3 said:
I've started looking at the edge under lights with my eyes. If I see glints of light, I need to do better.

This may not work for some. A loupe might help out.
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