How Not To Sharpen a Knife


I’m a fan of Gordon Ramsay, mostly because I can tell he is passionate about what he does (in spite of his extreme commercialism) – he’s an interesting character.

One episode of his cooking show, he was making pan seared scallops and it was a thing of beauty. But then I started to wonder (as I have pan seared scallops many times, myself) “how hard is that?” I’m not sure if Ramsay is that good a chef, or if he’s really just a good production guy.

Ramsay gives a lot of critique; I think it’s appropriate to give him a critique in return. Seriously, though, as a knife-maker I cringed a bit when he pulled out a knife steel. But then… Aie!

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Video editing is an art-form I am not very good at.

Comments

  1. says

    Dunc@#1:
    A steel is fine for a quick touch-up in the kitchen, IMHO.

    Once you know how to sharpen a knife properly (rather than banging it into things) you can sharpen on pretty much anything that is a good surface with the right amount of tooth and hardness. When I was a kid I used to use the top of a car window-glass, or a piece of paper or glass and toothpaste. The frosted end of a microscope slide is perfect for touching up the boshi of a katana, for example…

    A steel is terrible for an inexperienced knife-sharpener because the angle of the steel is variable due to its taper, and there is no flat surface to align a bevel to. My standard recommendation for a beginner is to either get a diafine diamond-impregnated stainless steel plate, which solves the flatness problem permanently, or to use 600-grit to 3000-grit wet/dry sandpaper taped to a flat surface, and some windex as a surfactant/lube.

  2. says

    These are what I use: [DMT sharpening plates] – the nice thing about them is that they are indestructible and always stay machinist flat. They also make an incredibly sweet curved sharpening steel called the “wave” which is wonderful for chisels and curved surfaces.

    A surface plate with sandpaper taped to it is good for up to about 3000-grit, which is more than most people require if they are not shaving with their knives. On the other hand, surface plates can be awkward to haul around.

    The fancy Japanese stones (I have a huge collection…) are, uh, fancy and expensive but in the end it’s all just abrasives and the diamonds sure are nice and the DMT plates are close to indestructible, whereas homeland security can drop and break your $200 Japanese stone in a fraction of a second. Homeland security will not even touch a machinist’s surface plate, though, because they’re usually too wimpy to move one.

  3. says

    Paul Durrant@#5:
    Those Dia-Sharp plates do look good.

    They are fantastic. I usually put mine on a silicone sil-pat so it doesn’t slide around, and spritz it with water or windex every so often. They don’t rust, they don’t get out of shape, they don’t ever dull – I have been using the same set for 20 years. Which is a whole lot more than I can say for Japanese water stones that cost 5 times as much.

    In the end, it’s all just abrasive. I keep meaning to make some abrasive blocks by mixing silicon carbide into resin and casting it in a silicone baking tray. “Ye giant polishing thingge”

  4. Dunc says

    A steel is terrible for an inexperienced knife-sharpener

    You need to learn how to use one, yes. And I’ll grant it’s not easy for a total novice.

    My standard recommendation for a beginner is to either get a diafine diamond-impregnated stainless steel plate, which solves the flatness problem permanently, or to use 3000-grit wet/dry sandpaper taped to a flat surface, and some windex as a surfactant/lube.

    Great for proper sharpening, sure. But when you’re in the middle of mise en place and your knife is just a fraction off, you don’t have time (and I don’t have space) to be getting out a plate or a whetstone. I just want to grab my steel and make a few quick passes to bring my knife back to proper sharpness.

    One thing I learned from a chef – you never, ever take a steel to somebody else’s knife, because everybody uses them slightly differently, and you need the consistency that only comes from muscle memory for them to not make things worse.

    Diamond steels, on the other hand, are a terrible idea and ought to be banned. A steel shouldn’t be removing that much metal from the edge, so there’s no need for it to be that aggressive. If you need to actually re-set the bevel, that’s when you get a proper whetstone out.

  5. says

    Dunc@#8:
    And I’ll grant it’s not easy for a total novice.

    Or for Gordon Ramsay, apparently.

    you never, ever take a steel to somebody else’s knife

    I won’t even use someone else’s knife, unless it’s a cheap piece of tactical flup that they clearly don’t care about. Although, if Gordon Ramsay offered to let me sharpen his I suppose I could whack them against a DMT plate a few times as a demonstration.

  6. says

    Note: the reason I said “as a knife-maker, I cringed when he pulled out a steel” is because a steel is a chef’s tool. As Dunc points out, it’s a tool for doing a quick touch up on a blade. To a knife-maker, that’s not a thing we do, there are no “quick touch ups” on blades.

    Gabriel Bell sharpens knives at a fair in Oregon, and a lot of professional chefs bring knives for him to sharpen and edge-polish. I’d bet that half of those have been brutalized with a chef’s steel for a “quick touch up” because pulling out a steel was faster than pulling out a, uh, a flat steel. Or something.

    Did I mention that those diafine plates are nearly indestructible? You can position them in your knife-roll so that they are on either side of the mass of blades and help protect them. Unlike fine Japanese stones, they won’t crack or chip.

  7. says

    That steel should not have a steel hand guard in the first place. it should be aluminium, brass or plastic, not steel. It is there to protect the hand against a cut, but it should be soft enough not to chip the blade when one accidentaly hits it. But yeah, bumping deliberately a sharp edge into a handguard is dumb idea in all circumstances..

    IMO, “angle consistency” when touching up with a steel is overrated. As is the precision of sharpening angle on a whetstone.

    Neither I nor my father have ever fussed about that sort of thing. When he taught me to how to sharpen knives, he has just shown me “this is how you hold the knife against the whetstone” and that was that. The same when he taught me to use steel. Angle was not mentioned once.

    I have tried steeper and less steep angles and I reckon that anything between 10 to 30° works just fine for any ordinary utility knife, on steel and on the stone as well. You might find some problems with edge retention or straightness between different angles if you really set your mind to it, and yes some angles are better suited for some steels/tools/materials/uses, but to be honest ordinary J. Doe with a kitchen knife doesn’t stand a chance at noticing anything. I do, but that is besides the point.

    Allegedly even the old fencing masters were never able to agree on an ideal way to sharpen and maintain a sword, and that to me tells that there isn’t one.

    So when I teach someone how to sharpen a knife, I tell them not to fuss about sharpenint angle too much.

    An anecdote: Recently I have managed to make an impromptu whetstone in the wild and teach a noob how to sharpen with it. He managed a passable cutting edge on a blunted and chipped (in fact nearly destroyed) knife on his first try. I have shown his girlfriend how to use steel the day before, and I demonstrated the purpose of the (plastic) handguard without banging the knife edge into it.

    I agree that diamond coated steel is an abomination, along with many other sharpening gizmos.

  8. says

    I have tried steeper and less steep angles and I reckon that anything between 10 to 30° works just fine for any ordinary utility knife, on steel and on the stone as well. You might find some problems with edge retention […]

    Edge retention is the issue. You can sharpen a right angle pretty well, if your target is hard tool steel, and it will cut fine for a little while and to a limited depth but edge sharpness is not the only thing you need to worry about. A second issue is binding in whatever you’re cutting.

    So when I teach someone how to sharpen a knife, I tell them not to fuss about sharpenint angle too much.

    It doesn’t sound to me like you or Gordon Ramsay should be teaching anyone how to sharpen a knife. If you’re going to be a professional knife-maker, “anything between 10 and 30 degrees” does not work. More to the point, if you have a blade that is bevelled for 12 degrees and sharpen it at 30, you’ve just ruined the edge and whoever comes along after you to repair the damage is going to have to invest careful hours fixing your handiwork.

  9. kestrel says

    That was painful to watch.

    I was surprised: he was sharpening **towards** himself, not away. I was taught to sharpen away. I was also taught that angle did matter: not all knives have the same angle on the edge. A knife meant to be taken out camping and used for just about any task would have an edge that is much thicker and stronger than one that only will face carrots and lettuce. I was taught to sharpen to the angle that is on the blade.

    We used to use the back of an old mirror for sharpening. It had just a little bit of grit to it and the glass was usually really flat. It worked really well, but clearly those DMT sharpening plates are far superior!

  10. says

    @Marcus

    It doesn’t sound to me like you or Gordon Ramsay should be teaching anyone how to sharpen a knife.

    *shrug* I think you did not read my comment in full and/or perhaps I worded it poorly.

    Perhaps I should have added that “telling them not to fuss about an angle” is not the same as “saying they should ignore the angle altogether and being haywire inconsistent with it on one blade”. I do mention that the steeper angle is better for kitchen knives and the opposite for camping knives and the upper end around the 30° is for chisels and axes. But in my experience what is more important than the angle itself is having a consistent angle on the edge of the whole knife, not the exact numerical value of the angle itself.

    Anyhow, I won’t toss my twenty years of experience with sharpening knives and various other utensils because my comment disagrees with someone’s opinion. I have taught multiple people to sharpen knives and none of them subsequently destroyed the knives they own. Neither did I, or my father, and knives in our household last for decades of intensive use before being worn out – and we sharpen them on stones at about three to six months intervals.

    More to the point, if you have a blade that is bevelled for 12 degrees and sharpen it at 30, you’ve just ruined the edge

    If we are talking about an ordinary symmetrically ground knife, then no, you have not ruined the edge, you have reshaped the edge. And if the blade is ground thin enough (which admittedly many store-bought knives are not) re-shaping it back to that steeper angle is not too much work either, a few minutes on coarse stone.

    Anyhow, 10° and 30° degrees are extremes, when you try to set the blade by eyeballing at an angle between these two you end about 99% of the time with around 20°.

    I have on youtube seen people measuring the angle with lasers before re-sharpening the knife, and then setting it on overcomplicated gizmos at “exactly 15,8°” because that was the value they read on the display and therefore it must be the ideal angle for this blade yaddayaddayadda. There is no way in convincing me that this is not absurd extreme.

  11. says

    kestrel@#13:
    I was also taught that angle did matter: not all knives have the same angle on the edge.

    Yes; if knife-sharpener you wish to be, you must read the angle of the edge and sharpen each blade at the angle it’s beveled at. Otherwise you’re rounding the edge. If you consistently sharpen the edge at the wrong angle then the wrong angle eventually becomes the new “correct” angle. But until then, you have a knife that will not cut well and will not hold an edge for long.

    I’ll have to do a posting on this topic, I see. And, as you can imagine, the internet being what it is, there are many many many opinions. Some of them are even right. A very small number.

  12. says

    @kestrel, interesting, because in my life I have only ever seen one person to use the honing steel with the “away” motion. Every butcher and cook that I have ever met uses it as shown in the video (without the banging of edge on the guard of course).

  13. says

    Charly@#14:
    If we are talking about an ordinary symmetrically ground knife, then no, you have not ruined the edge, you have reshaped the edge. And if the blade is ground thin enough (which admittedly many store-bought knives are not) re-shaping it back to that steeper angle is not too much work either, a few minutes on coarse stone.

    Perhaps it is a vocabulary thing. You just described taking an edge out of angle and then that it can be re-shaped back. That’s a nice way of saying “ruining it” and “fixing it.” I didn’t say “permanently ruining it” or “ruining the knife.” You’re describing putting the edge so badly out of angle that it needs to be re-ground. I call that “ruining” it and maybe you call that “sharpening” it but most knife-makers in the US would use the term “ruin” or perhaps “fuck up” but definitely “stay the hell away from my knife!”

    More to the point, if you can’t read the edge angle by feel, you are just going to ruin edges. One approach I see people do is pick what they think is good and grind edge away until they get it. Gabriel often has to do that with the knives he is presented because they’ve been sharpened with a steel or worse one of those kitchen grindy wheel things

    To read the edge of a knife, I use a very fine stone and a tiny bit of oil, position the edge forward, distribute the oil across the stone, and then try a very shallow angle and move the edge forward. If the angle is too shallow, the oil builds up in fronr of the contact surface, which is behind the edge, and you can feel it’s very slick. As you continue to feel the oil is lifting the blade from the stone you change the angle until suddenly it will feel a bit sticky and the oil will be swept cleanly off the stone by the blade. If the sweeping is spotty it means the edge is ruffled, probably by someone using a steel. If the sweeping is even and clean, that’s your angle on that side of the blade. Flip it over, repeat, and see if the blade has 2 different angles. If it does, the edge needs to be re-set and you have a lot of grinding do to. After you have some experience with this you can “read” a blade very quickly with 3 or 4 strokes and not even think about it. Basically, that’s the same thing a machinist is doing with a surface plate – when you have a mating that is so flat and tight it drives the oxygen out of the space between the object and the plate, and you can feel the van der waals forces, then you have the angle right.

    There are also, as you say, different grinds for different blades. If you grind a katana flat you have probably ruined not only the edge, but the sword itself, since reshaping the edge will take you up into the hamon. With a chisel, you grind it flat as a machinist’s surface and then put a micro-bevel on the very edge. With a modern knife, a lot of people grind a bevel, then an edge-bevel, and polish the edge-bevel; that is a wretched and lazy practice but a lot of people do it because it’s easy and it is all they know. And of course, hollow grinds are a thing; they’re intended to make it harder to screw up and form an edge-bevel by making that region small and narrow as possible. If you’ve ever shaved with a straight razor that someone has edge-beveled you probably will remember the experience as being unmitigated misery.

    when you try to set the blade by eyeballing at an angle between these two you end about 99% of the time with around 20°.

    If you are “eyeballing” it, you are wrong. “Eyeballing” is for when you don’t know how to read an edge. People who “eyeball” it usually wind up grinding the edge off and creating a micro-bevel which is sharp for a little while, but they’ve probably made the blade worse. The micro-bevel is almost always more oblique than the correct bevel because anyone who “eyeballs” a bevel is being lazy and they’re going to try to polish the edge and it’ll form a micro-bevel because that way they are removing the least amount of steel and it takes them no time to do this, compared to actually reading the correct bevel off the knife and polishing the bevel that exists. Re-sharpening a knife that has been treated that way amounts to re-grinding it and usually I take it to a surface plate with some 1000 grit and oil and try to figure out where the original bevel was supposed to be and see if I can get it back there.

    I have on youtube seen people measuring the angle with lasers before re-sharpening the knife, and then setting it on overcomplicated gizmos at “exactly 15,8°” because that was the value they read on the display and therefore it must be the ideal angle for this blade yaddayaddayadda. There is no way in convincing me that this is not absurd extreme.

    It’s the method they are using that is absurd, not the objective. If someone wants to claim to be able to sharpen a knife, they need to know how to read the edge angle by hand, without gizmos, and then consistently maintain that angle. That’s not hard. It’s what’s called “knowing how to sharpen a knife.” All those gizmos are a poor substitute for knowing how to sharpen a knife.

    It’s basically the same process you use to establish the bevels on your big belt-sander. You just feel where the bevel is and grind on that angle. It’s not rocket science. If you’re grinding a katana, you roll that angle toward the edge very slightly as you grind. If you’re grinding a cooking knife you hold it even. If you’re grinding a chisel you hold it flat, and if you’re grinding a straight razor you’re shaping the hollow and placing the hollow’s end right at the edge. If you know how to do basic grinding, then sharpening is the same process. Or are you going to tell me that you place the major bevels on your blades at whatever seems right between 10 and 30 degrees? No: you read the major bevel that exists or you set it where you want it. Same with the edge bevel.

    I’m comfortable rubbishing your technique. So what if you’ve been doing it wrong for decades? (shrug) It’s not so wrong that it’s obviously, wretchedly wrong, but it’s still wrong.

  14. Dunc says

    On a somewhat tangential note, every chef I’ve ever asked thinks that Gordon Ramsay’s (a) an arsehole, and (b) not a very good chef, so it’s probably not just his sharpening technique that leaves something to be desired…

  15. says

    I think what we have here is a failure to communicate because I think I have trouble getting across to you what I actually mean?

    A knife completely re-ground to a different angle is not destroyed, because it will cut, and it will still cut well – unless, as I said, the blade is overtly thick, in which case it is a knife unsuitable for kitchen use in any case. And arguably, a knife with 30° angle will cut worse but have better edge retention than a knife with 10°. Both extremes have pro’s and con’s and if you gain on one of the two, you lose on the other. So no, neither a knife with acute angle or less acute angle are “rubbished”. They are different, but they will both cut your ingredients for dinner and they will both cut your finger off if you are not careful.

    So if you re-sharpen a heavy-duty camping knife at too acute angle, all that happens is that you will have to sharpen it more often (and that first change of angle will take you a long time). If you sharpen your kitchen knife at too steep angle, all that happens is that you will perhaps have trouble cutting soft tomatoes and you will cry a bit more when cutting onions. But you won’t notice a thing on carrots or potatoes (well, you would, and I would too, but ordinary J. Doe used to store-bought knives – no).

    “Eyeballing” the edge to me is looking when the bevel is in contact with the stone, then looking how high the spine is from the stone at that position and maintaining that height. On knives with visible, strong flat bevels I do, in fact, try to “read” the bevel as you describe it, only not with oil on flat stone, but with feel, because there is distinct albeit very slight “skip” for want of a better word when rolling the blade on the stone. Then it is the same – how high is the spine at this position?

    Rubbish all you want, but unless you show me actual tests, performed blindly and independently of personal biases, we are both just talking opinions. I am not aware of any such tests being performed, but maybe there was some scientist somewhere who performed them.

    And I am talking about kitchen knives, not katanas or razors, those are both very special tools with very narrow and specific properties. I have never said that a razor sharpened at a steep angle is just as good as any.

  16. says

    @abbeycadabra, you are right.

    Marcus, I did not intend to start a fight and if my first comment came off as too blaisé, disparaging and dismissive or perhaps derogatory or fight-picky, I do apologise for failing to communicate properly.

    I think that the comment-format is not suitable for this talk and that in an actual workssop with actual tools in hand we would both more agree than disagree on the generalities and minutiae of knife-sharpening.

  17. voyager says

    Those sharpening plates look like a good idea, but is it difficult to learn how to use one properly?

  18. dangerousbeans says

    “Why don’t you just sharpen your knife with your fine abrasive personality?”
    i’m too fucking coarse for final sharpening

    @ Voyager 22
    It takes some practice, but with some time you can get decent results. IMO, passable knife sharpening is not hard. really good knife sharpening is the hard one

  19. lochaber says

    I really like the Spyderco Sharpmaker system. It can be a bit tedious for larger blades (I think the largest I currently own is maybe ~14″, and it doesn’t get much use, and therefore much sharpening…) Mostly I sharpen my pocket knives and chef’s knife with it.
    It’s a pretty easy to use system, doesn’t require lubricants, cleans up well with some scouring powder, and works pretty well for odd blade shapes like kukris, recurves, hooks, etc., that can be hard to sharpen on a typical whetstone. Also can handle most serrations reasonably well, but I’m not terribly fond of serrated blades, so… It also packs up pretty well, so I found it great for when I was going on trips and such.

    But, as to chef’s steels, I had often heard that they weren’t to “sharpen” as much as they were to “realign” the edge. That they weren’t meant to remove material, but that during use, the finely sharpened edge of the blade may “roll” or bend to one side or another. Using the steel was supposed to help undue/reverse this, and be done periodically during use of the knife. This also involved dragging the knife along the steel in a spine-first direction, and I believe, typically away from the hand holding the steel. A guard is still a good idea, because well planned things anticipate imperfect use, and all that

    But, that only really applies to those smooth steels, and pretty much all of the steels I’ve seen the past couple decades (not a chef, and don’t spend a lot of time looking for them, so, my sample size may be a bit small…) are either the scored type like Ramsay was using in the video, which I think are not much different than a circular file, or the diamond-coated ones, which, again, aren’t too much different from a circular file… I remember coming across one in college, and hanging on to it, not because it was a good steel, but because it was a really aggressive file, and great for reprofiling an edge, or for doing the rough work on a blade with chips, dents, or extensive flat spots. After that, I’d switch to something finer grained.

    Also, end-grain cutting boards.

  20. hannahbaker871 says

    Pocket knives are the best and widely used utility tools. They are used to perform lots of tasks of our daily routine and therefore, they tend to lose edge fastly especially if they are made up of stainless steel. The blades of pocket knives can be sharpened by a number of tools. The most common ones of them are steel and whetstones.

  21. says

    hannahbaker871@#26:
    The blades of pocket knives can be sharpened by a number of tools. The most common ones of them are steel and whetstones.

    I used to sharpen mine on the upper curve of a car window. Of course, I was not trying to achieve a fine or straight edge.

  22. says

    I’d like to apologize if my reaction to some of the comments was a bit harsh.

    When I edited the video, I sent a link to a couple of friends and – from the small set – nearly half of them engaged in protracted e-mail debate about the topic. By the time the comments started here, I was thoroughly sick of it and got snappish.

    Knife sharpening is one of those topics like “is it art?” that invites a great deal of opinion. As the poster of the topic, I either have to fall back on being authoritarian or I have to (as Charly suggests) try evidence and experiment. His challenge poses a neat dilemma, since I don’t believe it’s possible to experimentally support something that is a multi-variable set of trade-offs most of which are subjective, anyway. So I’m taking that as a conversation-killer and I’m not going to pursue it further because I don’t want to seem like I simply must be right.

    When it comes to knife sharpening, because I make everything from chisels to straight razors to chef’s knives and katanas, I have had to learn how the edge geometry and sharpening strategy combine to produce the best (subjective) result. That means that I had to develop an understanding of edge dynamics on a per-edge type basis; I can’t just say “oh, that applies to a cooking knife, not a katana” – I have to understand why the edge of a flat-ground cooking knife is different from the edge of a katana, before I can sharpen either. But what about an S-ground cooking knife? That also means I don’t want to get down in the weeds just about cooking knives; once you understand the relationship between the edge geometry and how it’s sharpened, stuff like the cutting edge angle versus blade durability tradeoff makes a lot more sense.

    I’m not sure if I want to wade in and try to do a series of postings about the underlying principles of knife sharpening, or not It might be too much work and, as I think about it, there are still going to be aspects that are “that’s like just your opinion, man.”

    Anyhow, I’m sorry I got defensive and grumpy.

  23. says

    there are still going to be aspects that are “that’s like just your opinion, man

    Welcome to the daily life of artists who try to discuss art among themselves!

    Seriously, though, I don’t think there’s a problem with discussing subjective topics where “that’s just your opinion” is uttered on a regular basis. I’m not exactly an expert about knife sharpening, but I have gotten an impression that there are some similarities to discussing techniques for making artworks—there is no single correct way how to sharpen a knife, instead there are various options how one can get a good or at least a subjectively acceptable result. Simultaneously, there are also wrong ways how to sharpen a knife—methods that result in risking injuring yourself or damaging the knife. Thus it’s possible to discuss the topic, despite the fact that some subjectivity and “just opinions” remain there among the facts. As long as everybody remains polite, a discussion is possible.

    By the way, discussions among artists about how to make a painting are even worse in terms of how much subjectivity and opinions one will encounter. The problem with discussing art is that artists cannot even agree about what kind of end result is desirable (namely, how a finished painting should look like). With knives people at least can agree that they want them to be sharp.