Why Knife Sharpness Is Not What You Think

[@OUTDOORS55]

My wife is currently using this knife to cook dinner, and she was amazed how sharp it was😉🤫

[@citizenatlrge]

That's what I'm saying! It'd be tedious maybe, but shit, I bet you could make these and sell them for kids/novices to safely learn faster knife skills with.

[@LuchoTiz1]

🤣🤣

[@Somethingforyourmind01]

Best thing is:it cuts groceries like nuts yet it probably can't cut her fingers . 😁

[@diavalus]

This is similar to when some people claim they used their honing rods and their knives turned ‘razor sharp’. They have absolutely no clue how a real razor sharp edge cuts like.

[@joso5554]

@@diavalusexactly. Or they are very good at making their razor blades dull after a single use. 😅

[@Christophe_L]

Did you just invent the Safety Knife?

[@AtticStinky]

Thing is sharp knives cut better so the wound will heal better. Sharp knives can be safer than dull knives. That thing is going give you a pretty nasty scar even if you manage to cut yourself with it

[@qwerty81808]

@@AtticStinky Not quite. The reason sharp knives are considered safer is because they are less likely to slip and accidentally cut you. They are more predictable, and therefore safer.

[@troyelder56]

Actually safety knives specifically child safety knives are a similar concept to this. Ceramic safety knives use a squared edge but are great for cutting things like food which is often their primary purpose so you can teach kids how to cook and help in the kitchen.

[@human678]

I have been very glad my knife was dull at work many many times. Accidents happen with sharp and dull knives and with a sharp knife I would have a lot more stitches.​@@qwerty81808

[@Layarion]

@@AtticStinky a knife this dull *cannot* cut you accidentally. ever. you can literally swip it across your fingers and it won't cut you.

[@switchbeck6673]

I love that your demonstrations show how complicated knife sharpness really is

[@RandomSadBoomer]

It's actually quite simple if you take some time to learn how the knife works.

[@MiguelReyes-yl3bp]

The power of geometry

[@RandomSadBoomer]

@@MiguelReyes-yl3bp and physics 😀

[@deucedeuce1572]

...and how simple it really is too.

[@DJ_POOP_IT_OUT_FEAT_LIL_WiiWii]

I think knife sharpness is what you think.

[@Somethingforyourmind01]

Yes ! Finally you explained something that bothered me for a while. I am into sharpening for some years now. I sharpened a few knives to a point where they shave and glide through a paper with no resistance. Yet they perform bad in kitchen and this is the answer . Apex is sharp as hell,but geometry of the knife is bad,its too thick behind the apex.

[@jameshaulenbeek5931]

A great analogy to this is comparing European and Japanese chefs knives. They really are meant for different tasks.

[@sdrtcacgnrjrc]

Can you explain which different tasks? Thanks in advance ​@@jameshaulenbeek5931

[@Somethingforyourmind01]

@@jameshaulenbeek5931 True. I have Santoku that has nice geometry,its thin. A great knife.

[@thebiggestpanda1]

This is why hollow grind blades can be better than flat or saber grinds. You get the thick spine but because of the hollowed out bevel, you can get really thin behind the edge.

[@Somethingforyourmind01]

@@thebiggestpanda1 Yeah. The Santoku i mentioned earlier is perfect knife . It's good for most of the tasks in the kitchen. Its spine is thick,but it thins down perfectly to the apex. I mean,its not just Santoku,there are many knives made that way. And for us that sharpen em and just recently discovered the geometry problem is much more satisfying to cut with such knives. :)

[@sacoto98]

And this is one of the biggest problems I see with a lot of custom kitchen knifes. A lot of bladesmiths don't understand what it takes for a knife to perform well in the kitchen. I see so many videos of bladesmiths showing off their knifes gliding through paper and then I look at the choil cross section of the knife and I see something worthy of being almost an axe.

[@twatmunro]

It's why people have an affection for Japanese "factory" and small workshop knives over proper "custom" knives -- even though they might cost about the same. The Japanese have got cutting ability dialled in. You can't be making knives for sushi and sashimi chefs and be turning out some big fat slab of a kitchen knife.

[@TimJohnson-x1o]

heres an idea. dont go to boy brained EDC bro bozos for kitchen knives. common example of this garbage, meglio or whatever his name is. Try going to kitchen knife bros for kitchen knives and ask them. the difference between edc bro world and kitchen knife bro world is night and day. one is full of adolescents boys and the other is full of adult men.

[@MACTEP_CHOB]

They are unforgivable if not used properly. Most ppl probably should stay away. @@twatmunro

[@mrkiky]

This is why a chef knife is one of the hardest types of knife to make.

[@drd1924]

Totally, I see way too many people wanting to get in the Fad of being a knife maker, thinking their product will demand $1000 per blade just because Reeves does.....yet with little to no research of understanding what they are making. an ADHD Generation looking for something to occupy their attention because they need a hobby, which is fine... but then thinking they're an expert. There are very few custom knife makers I see that know what they are making from experience of what the blades intended use is.....skinning knives being a prime example

[@THSP31011]

Cutting is just pressure over area. So regardless of angle, if the area is small enough and the pressure is great enough, it'll cut.

[@OUTDOORS55]

Exactly 👍

[@igordzuro4353]

Growing up I was fascinated by how knives actually cut stuff. Learning this principle of how knives are supposed to work led me to sharpen and even make knives 👍

[@joso5554]

I don’t agree 100%. What you say is exact for cleavers, axes, and chef knives used in a purely vertical cutting movement onto a cutting board. But for most uses, a knife is used in a sliding motion, not just a vertical pressure. That sliding creates a shear effect, which is when the microscopic shape along the edge (micro-serrations from burr, e.g.) can have a significant influence by contributing to a « saw » effect which would play no role in a vertical cut. For that reason, I’m not so sure that the knife in this video wouldn’t risk cutting fingers easily in such a sliding motion… But I won’t volunteer to test it!

[@igordzuro4353]

@@joso5554in a way oofman is still right even in the situation you're describing because microscopic serrations sitting in a row in a formation called "burr" or "hair" are so tiny they create a lot of pressure and thus are able to "cut". This is why machinists use a "deburrer" on corners because even very defined 90° corners on a big part that don't have a bevel and seem very "thick" as opposed to a thin knife edge can be left with a burr after machining that can lead to very nasty cuts. Trust me...

[@ashleymiller7439]

I learned about that the hard way my 3rd day on the job as a line cook. The sharpest things in a commercial kitchen are not the knives but instead things like the edges of stainless steel flashing on the walls and various unfinished edges around the line and prep sinks. @@igordzuro4353

[@allanknives]

Never a dull moment in this channel that’s for sure 🔪

[@glennac]

😂 That was worth a thumbs up. It’s as clever as a toilet lever.

[@OUTDOORS55]

I see what you did there😉

[@JamesStripling]

Yeah! This whole episode had me right on the edge.

[@sirspongadoodle]

@@JamesStripling i was edging to this video...

[@paulkresky1465]

You are, as you said, just scratching the surface of this subject. As a person who was trained by Sami (Finnish Indigenous) knifemakers as a kid. (Traditional Pukko and filet knives), and as a major trapper up near Canada when I was a kid in the 60's and 70's, there was a great deal of debate and opinions on how sharp you want an edge. For different uses. Most real hunters and trappers back then, me included, wanted a very sharp boning and filet knife with a very thin blade. ( I used a Canadian belt knife for that. Also called Green River knives) And they had just come out with the hip pocket size "safety" boning saws that fit in a leather belt sheath. Some used their hatchet for that. Buck 110's were all the rage, and quite revolutionary back then. Whether a person carried one of those or a sheathed fixed blade hunting knife, there was great argument over whether you wanted a "toothy" edge, or a refined smooth, apexed edge. That debate still continues. I carried one of the original Schrade Walden HS1 Honesteels in it's leather pouch on my belt. Those were covered in chromium carbide oxide coating. (Some butcher steels had, and still have that today.) Chromium carbide was like the "diamond stones" of the time. They do peel steel off the edge of the knife, but they leave a rough toothy edge. That made cutting meat and game a breeze when deep in the woods, and not a cabin filled with proper gadgets. As a knife and sharpening guy myself, I preferred the toothy edge for the field. A properly apexed and hair whittling knife edge would break and roll over too fast during heavy use. A more toothy edge lasts much longer in the field. Herein is why I think even experienced knife guys fight over gadgets and methods. Some only want mirror polished razor edges. All the time. Other people could care less about perfectionism all the time. And are perfectly fine with rough, toothy edges. There are so many preferences. And different knife edges, thickness, angle, etc. are meant for different uses anyway. As you well know. (Another big debate was softer steels versus harder steels, and which was better for field use. I preferred high quality 420HC. Easier to sharpen in the field, and could get pretty darn sharp.) P.s.- Schrade Honesteels have been garbage for a long time now. Thanks again for your videos Alex, even though we don't always agree. Hope you make enough money off your videos, and your Amazon links to make it all worth your time.

[@mikafoxx2717]

Toothy edge is my go-to. Plus you only need one stone. Or in a pinch, a river rock. (Went from flat blade screwdriver dull to pretty dang sharp)

[@mantzbrinkman4780]

@@mikafoxx2717 I have a lot of nice kitchen knives. My favorite one is made of two hardness types of steel that are interwoven (Damascus type). I am able to get it quite sharp and as that sharp edge wears, the difference between the softer steel and the harder steel creates micro serrations. At least for kitchen use, it is my favorite. It seems to hold its sharp/useful cutting properties the best and is relatively easy to retouch the blade when needed.

[@paulkresky1465]

​​​​@@mikafoxx2717 Good river rocks, huge flat rocks, or outcroppings, ledges, have some of the best sharpening stones you can find. I am from the Great Lakes area, so imagine what those rocks are like. When a person is deep in the woods for extended periods of time, you don't have room to pack much. I don't call being in the woods, being at the cabin! 😂 You need tools that work, and can save your life. For long periods of time. That doesn't equate to being in my shop, barn, etc., where I can hand sharpen to razor edges, which I also love. For the "real woods"? I prefer my toothy edge that cuts well, holds up well, and is easy to maintain. I carry two stones. One for back up. And use natural stones in the field all the time. (P.s.- to all the keyboard warriors who only preach "razor edges", and criticise anything else, I have three words for them to show they are being hypocritical, and don't realize it. "Serrated steak knives!!") (Lol) (Many different types of edges have their place in different scenarios.) It's no different when you are in the field. Especially as an on foot trapper. Technically, ALL knives are serrated. It's just what degree of fineness those serrations are. Thanks for your reply. Have a good day!

[@Yupppi]

Thanks for a good read. I suppose Saami people are sort of Lapland indigenous, spreading across nordic borders even, fun to find them mentioned randomly on a comment.

[@paulkresky1465]

​@Yupppi Exactly. They are nicknamed The Reindeer People as traditionally their lives depend on the reindeer. And they travel around with the herds when the herds migrate. These people are also in parts of Russia as well. They are the originators of the classic Scandinavian knife designs. Both Puuko knives, (think Mora knife), and the classic filet knives. They also originated what we call the Scandi knife grind. Along the way the Scandinavians came up with their own special blend of steel that was traditionally called Sandvik steel, as the Sandvik area was famous for it's forges and factories cranking out that steel blend. "Sandvik" steel is still probably my favorite overall everyday use knife steel. Tough, very rust resistant, easy to sharpen, gets razor sharp, and is easy to hand sharpen and maintain in the field.

[@stuartdavenport2952]

"Geometry cuts, heat treatment determines how long" - Roman Landes. And I would add that as long as the steel is a cutlery grade steel, the actual steel really doesn't matter. I never ship a knife that cannot cut a sheet of printer paper with just the primary bevel geometry (i.e. not sharpened). If it won't cut the printer paper, the geometry is too thick. And it isn't just about the thinness, either. Food release is important, and to that end a slight convex above the edge is key.

[@wozzlebaby5313]

What thickness do you recommend for a kitchen knife for most household mothers? 0.020" thickness maybe with a sliiiight concave above the apex?

[@kymcopyriot9776]

Thanks! And this is what drives me nuts about most of the current crop of pocket knives. They usually have relatively thick stock, are usually flat ground and thick behind the edge. So the moment they lose their sharpened bevel, they cease to cut because the geometry does them no favours at all. We need more hollow ground pocket knives!

[@OUTDOORS55]

Same here👍

[@RandomSadBoomer]

There will never be more hollow ground pocket knives or knives with thin stock. The reason is quite simple: too many people use knives the wrong way! No, you should not use your knife as a pry bar! No, you should not use the knife to baton the stupid log! The manufacturers will use insane thickness stocks as long as people will use knives incorrectly. PS: Boker Atlas is the king of pocket knives

[@Bob_Adkins]

Amen. Only a few folder users really benefit from a thick edge, or even a thick blade. Not many baton or pry open oysters with their EDC!

[@AnAntidisestablishmentarianist]

My CIVIVI Elementum is hollow ground.

[@MrJayGoliath]

To quote Dr Larrin : edge geometry. Super steel with super HT still don’t cut it

[@FireZenix]

Your videos are really amazing, keep them coming hehe. But as a knifemaker myself, I couldnt believe that a dull knife could cut well, then one day I just tried it and was blown away. I knew from other makers that blade geometry and thinness is everything, but its a different story when you feel it first hand.

[@OUTDOORS55]

Its amazing once you feel a really thin blade😁

[@jameshaulenbeek5931]

The nasty cut you can get from a feeler gauge will reinforce this.

[@krazmokramer]

@@jameshaulenbeek5931 Cringe! Been there. Done that.

[@gedfi]

​@@OUTDOORS55It's even more amazing when you feel a thin *sharp* blade.

[@jez76]

I have an old set of Global knifes, +25 years old, and when I started learning sharpening I have constantly thinned them behind the edge every time I do a proper sharpening session, and while the knifes themselves are nothing fancy they really can split atoms when they’re “fresh”. Edge geometry is a hell of a thing.

[@JoeSevy]

I've been sharpening for roughly 50 years, and if I hadn't seen you do it, I wouldn't believe it. I still won't really believe it till I do it myself. Great video!

[@AlarKemmotar]

I recently made my first couple knives. On my second one, I put a primary bevel all the way from the spine to the edge like he did here, but then also sharpened the edge up too. I've been amazed at how smoothly it slides through just about anything I cut with it.

[@popaionut5270]

I am following your videos from about 4 years and i learn a lot from You, i had buy from your links and i can Sharp knife tò cut hair but never tò pull hair on knife and tò bite....You are good ,people for sure Dont understand how Sharp that Is....

[@SL-jo4om]

Wow! This video is THE single most informative explanation and demonstration of both the theoretical and practical aspects of knife sharpening. Great production quality too. After watching this and a few of your other videos (including the one linked to at the end), I suddenly understand why my attempts to durably sharpen my own knives over several years were so fruitless. It's like a Road to Damascus moment (pun intended). Thank you for this amazing content.

[@btall3833]

The best knife content out there. I started sharpening knives in the 90’s with a Lanskey, it worked and taught me about correct angles, but I was always looking for something quicker, better, etc. I’ve tried paper wheels, Work Sharp, whatever was touted as the latest and greatest. After I started watching your content, I finally was confident enough to switch to free hand sharpening. What a difference, so much more satisfying, thank you for sharing your knowledge and skills with all of us who appreciate having and using a sharp knife. Looking forward to your future videos! God bless you and thanks again!

[@jacksmack2382]

Really like this new series of videos you are doing on sharpness, sharpening, and edge retention! Thank you for doing it.

[@Count_Smackula]

Never thought about it before, but now that you mention it, the knife I almost always reach for first in the kitchen has the thinnest blade.

[@carazy123_]

As someone only a little familiar with knife edge geometry, I’d expect a worn (dull) knife to have a rounded, not square, apex. Does wear actually result in a square edge? It seems to me that the squared apex creates a false edge that still aids in cutting, meaning it is still “sharp” to dragging motions.

[@setonsun5315]

Excellent information, great video. In my experience cutting a soft tomato has been the best example of a honing rod giving an advantage to a dull knife, and in that specific case the micro serration from forming a slight burr would cause the tomato skin to more easily split.

[@haqvor]

Those "laser sharpened" knifes (do they still exist?) with very aggressive serration took that idea and made a market of it. They didn't really cut anything but with a lot of small points they basically tore the food apart.

[@sdrtcacgnrjrc]

​@@haqvor I like a good saw in the kitchen

[@LogisticallyMisrepresented]

​@@haqvor... Tearing to release the flavor 😸

[@skilletborne]

@@LogisticallyMisrepresented If the food is in two halves, accurately and easily, why does it matter?

[@Narapoia1]

I've got to the point where I have been trying to get away from the honing rod approach for hopefully longer lasting sharpness with stones + strop. Have produces edges that cut through paper with far less resistance than the honed knife, shave like a razor, but are far worse to cut a tomato. My $6 victorinox knives cut tomato better than the razor sharp blade that costs 100x more (It was a gift and got me into sharpening). Is reasonably frustrating, but I am getting better results finishing on 1000 grit and very light honing.

[@fuzzynuttz5092]

I found that when you make the scratch pattern on your secondary bevel run in a diagonal direction, it helps form the micro serrations that you want for the blade to have that "bite"

[@meschnik2548]

never thought about this but i guess it could help

[@haqvor]

For some tasks it is important for the performance. For example a hunting knife doesn't benefit from a high grit mirror finish, if you stop at about a 1000 grit you create the micro serration that gives it a better bite with such a more heavy duty task.

[@fuzzynuttz5092]

@haqvor yea, and I would give it a couple of passes on a strop with 6 micron gunny juice

[@lordchiopet1630]

Always love seeing the subtlety and nuance brought forward in stuff like this. There's a lot of ways to get the same job done and I would've NEVER guessed that was a flat edge you were cutting with

[@guyindisguise]

Found your channel just recently and binged a couple of the newer videos but now I'm confused. I just want an easy time cutting in the kitchen and was planning to get a Shapton 1000 as you recommended in another video. Is it better to get a thin knife for kitchen work than learning how to sharpen my existing knives? Do I need both?

[@OUTDOORS55]

This is just a demonstration. I wouldn't actually use this without a secondary sharpened bevel (unless you count tonight since I made dinner with it😉) Use your existing knives and learn to sharpen. But of course if youd like something higher end thats up to you. Thin knives are expensive due to the time involved in making them🙂

[@shawnbottom4769]

This video is a masterclass in presentation and concept progression. Well done.

[@scuffmacgillicutty7509]

I'm very new to your videos and mirror many of the comments here praising your work. I just got some glass 320 and 1000 stones and you've helped me go from terrible to actually getting a burr and an apex on my first sacrificial 60 year old carving knife. Many thanks for that. In case you've never heard this you have what I think could be a twin out there. He also works in metals industry and goes by the name Mark Yaxley - CEO of SWP. Cheers.

[@albertosara416]

I knew sharpening wasn't an easy matter from watching your other videos, but this one really put a lot of things into perspective.

[@citizenatlrge]

FFS I'm in LOVE with this series. I hope you put all of these in a playlist that I can add. Additionally, you just gave me the great idea of thinning and squaring a knife specifically for my 14 yo to really begin learning with. I'm stoked to break out the 1x30" HF belt sander lmao.

[@EUSilverleaf]

I've been binging your videos. Stellar quality, nice job. You take a scientific approach, you prepare and theorize, iterate, and show your work. I'm incredibly impressed by the amount of work you're putting into this. As a beginner in hobby knife sharpening, this is super helpful. I've learned: -Leading or trailing edge makes little/no difference. -If you're going to use compounds to strop, use a high grade diamond. Otherwise don't bother. -Waterstones (aluminum oxide) are best ignored by beginners or people sharpening higher quality steel knives. -A blunt knife can cut pretty well actually. -Working a coarse grind (around 300 grit) makes a knife edge sharp enough for most people to be acceptable. I'm considering the following: Your onion cutting was a push-cut. While geometry might get the blade through the onion, a sharp edge gets it through the first layer, I think. So what happens when you cut a tomato with that blunt knife? Does it smoosh? The point wasn't to start cutting all your veg with a blunt knife, I get that. But it does lead me to wonder what the effective use of the secondary bevel is. Because simply, my knives get duller over time, and they don't cut as well. But the primary bevel doesn't diminish. The secondary bevel must be involved. I'm missing something here, and I wonder whether your could elaborate by commenting, if you do have the time. Thanks again for making these videos!

[@SpaceMonkey23101]

Only recently found out about 'blade thinning' and applied it to my kitchen knives. Amazing improvement! It needs to be talked about more.

[@dragoscoco2173]

Wait till you find out about grinding shallow grooves on the sides for the kitchen.

[@francoutah]

Thank you for giving us your knowledge and teaching us such valuable skills. You're an excellent teacher and I am a big fan of your hair widdling demonstrations. You are the real deal. I should know. I've spent 35+ years working in professional kitchens. I myself have taught hundreds, if not thousands of people how to cook and sharpen their own knives. Keep it going!

[@doid0666]

You're starting a revolution here, sir. I'm really glad buying a Honing Steel brought you more video oportunities, and I really hope this knowledge gets spread out so people can start selling better 1 dollar kitchen knives using geometry, and so obviously other knives also get improoved.

[@cavemandanwilder5597]

Great breakdown. It took me a loonng time to fully appreciate this, so I’m glad every time I see a good explanation of it intended for beginners.

[@brakeme1]

You have really developed well over your KZbin career. You have pulled ahead of the pack . Neat to see. I am a professional sharpener who sharpens roughly 600 knives per week....but trained on salon shears with convex edges.

[@Tsxtasy1]

Idk what sparked it. But your video quality (production, equipment, story, delivery) has taken a big jump upward recently. And you started from a place that was already good. Keep up the good work!

[@MrBearbait75]

Good stuff! Keep going on this series! Love your delving into the details of what makes sharpness!

[@erictjones]

Thanks for acknowledging the small serrations possible affecting the results.

[@dragoscoco2173]

Those are milquetoast food items that can be cut with the back of the knife as well. When you get into tendons, skin or even the humble Butternut squash, that primary is just not enough.

[@jchart]

You're my favorite knife-related channel and it's not even close. Keep up the great work! Very good educational content.

[@dooshlerd]

Ok this is just outright cool as hell. I would have never thought that a knife with no apex could actually cut anything with any precision. I've learned an unreasonable amount about the physics of sharp edges from this channel.

[@meschnik2548]

okay, with this you surely got my sub for sure. i was sceptical about the honing rods etc. but this makes pure sense on a broad and detailed view. greetings from germany

[@OUTDOORS55]

I appreciate the sub🙏

[@TheYoutubeUser69]

diamond/ceramic honing rods do work, no? so only the cheapo metal ones are problematic

[@twatmunro]

@@TheKZbinUser69 -- When I bought my first "good" kitchen knife -- a Wusthof -- I also bought the Wusthof ceramic honing rod to go with it. It does remove steel. However, it doesn't remove it fast enough to have any discernable effect on sharpness that I can tell.

[@davidrees1840]

I imagine the $1 knife would perform really badly if the square edge was polished rather than rough. I think many materials 'cut' better with micro saw teeth vs a scalpel edge. Excellent thought-provoking video as always, and Happy New Year!

[@nunya___]

I once had a set of "lazer" kitchen knives with micro laser cuts that went 1/3 up the blade geometry. They cut great and lasted years, never sharpened.

[@kingoietro99]

@@nunya___das cool

[@michaelleue7594]

So what are the drawbacks that prevent kitchen knives from being smithed like this? It seems like a knife that cuts food great and skin badly, and retains an edge indefinitely, would be ideal for that setting.

[@LarsPallesen]

That's actually a good question.

[@supernoobsmith5718]

Same level of sharpness across the blade is important. The most dangerous kitchen knife is not one that is too sharp or too dull, but one that is sharp in one place and dull in another.

[@hubertstaller1]

This is exactly what I observed in the last years, but never seen or read before. And it is probably why I like my Robert Herder "Windmühlen" knives for kitchen use. No fancy forging, no super fancy carbon steel, but grinded by hand to achieve a thin primary bevel, what they call "Solinger Dünnschliff". While I really should sharpen them for Tomatos, for most kitchen tasks they are nicer to use than thicker knives with a better apex sharpness.

[@samueldougoud3289]

Good video, I am glad that you confirm my intuition. This is why Opinels (single bevel) are so sharp / easy to sharpen, or why the basic Victorinox kitchen knives keep doing reasonably well even if dull : they are thin. By the way, this is the very rationale behind peening scythe blades : having a thin (around 0.25 mm behind the edge, 10° angle) secondary bevel. Rule of thumb about when to peen : when the whetstone "does no longer work" - in other words : when then secondary bevel gets too thick... 😉

[@ARAW-__-]

So many people need to start watching your videos.

[@NeevesKnives]

as the saying goes geometry cuts

[@iPKnives]

I saw the 3 videos and am very happy to say I learned a few things on honing rods and more. If you want to use food to test sharpness, I think tomatoes, fish skin, pig skin and tougher stuff are the way to go. Anyway, what can I offer my knife customers in stead of a ceramic honing rod? I know for a fact that people are scared of stones and other bulky stuff. There should be a diamond sharpener with a handle (just like a honing rod) BUT with a leather strop on the other side... maybe I'll try to make one off those.

[@joso5554]

I believe there actually are diamond coated « honing » rods. Besides ceramic rods and classic steel ones. As of food for testing, I may also suggest kiwi fruit (similar to tomato, actually) and hard cheese like old Mimolette (orange, very hard) or Parmigiano Reggiano.

[@dragoscoco2173]

2$ scythe sharpening stone. Excellent results can be achieved with bubblegum change.

[@johnduffy6546]

As a knife sharpness maniac myself, I think you did an incredible job of explaining the physics & geometry!

[@1495978707]

I just bought the book in your description. Good guy doing good work made a good book at a good price, so it's a no brainer to support that

[@raydurni1175]

You made me get hooked on sharpening! Another great video. My grandpa was good at it. I could never come close to his skill. He used a washita white stone. I'm still not very good at it but now I have the basic skills thanks to you. It's an art which requires lots of practice!!!

Actually... this is what I want to know. I don't use knifes to cut through thick plastic or wood. I use them to prep food. I don't care that much if it cuts paper well or if it can split a hair in half or if it can shave my face. The question is, can it make my time in the kitchen more pleasant and easy? What if I get my knifes and sharpen them in that way, just caring about the primary edge and forgetting about the apex? will they crumble? will they last?

[@slo_carry]

Love how you always give great explanations

[@undersky596]

Next questions I have now is about geometry and edge retention. I have a everyday use kinda camping survival style knife, it has a massive primary compared to secondary. I've often wondered if I should adjust the geometry to make it "sharper" but have wondered whether that's important for its edge retention at more brutal tasks. I realise this might be a very silly question and nuanced answer.

[@OUTDOORS55]

Not silly whatsoever its a really good question. Generally speaking thinner edge geometry always improves edge retention. At least until you run into edge rolling or other serious edge damage. I left a link to a book in the description called knife engineering by Dr larrin Thomas. Its a GREAT book with all kinds of info on this. Or check out knife steel nerds website👍

[@sebasbecu]

Please do a video for long lasting sharpness for kitchen stones. Thanks !

[@rudy1143]

Killer video. I don't give a crap about knife sharpness in my day to day life. I'm tangentially aware of it in a hobby perspective, and have seen knife reviews on incredibly sharp blades and have found them fun. As an engineer, I appreciate the brevity and focus of this video. I can instantly turn this around to practical application in my life. The algorithm insisted I watch this wild card of a video for good reason.

[@bentravis99]

Thank you for all the information you have been presenting lately! Amazing info and your close up photos are really appreciated to help understand what is going on as well.

[@n3hrox]

Could you also do a video about edges from custom knife makers? Like what's the real difference between s-grind, convex, flat, full flat etc? What's its role compared to primary & secondary bevel?

[@Toasty27]

and here i was always confused why people where perfectly happy with their dull knives, not even realizing how dull they were

[@kingofank]

Very cool demonstration. I think the knife will retain its edge until it isn't. Not until it doesn't, that would mean it ceases to retain the edge, until it isn't, in that it's so thin the body of the knife itself will wear away very quickly, and you won't have a knife anymore. Sort of the equivalent of using and sharpening a knife so many times that the blade gets whittled down, except much faster because there's less knife to wear away.

[@miker5502]

Great explanation…this is why a great big honking thick Bowie knife sucks at deboning a trout..lol😊even though it might give you a great shave and whittle hair. The edge behind the edge is too thick. You nailed it by saying this is just scratching the surface. Keep them coming! Cheers MikeR.

[@nobodyatall7039]

I'm a professional butcher and I can confirm that the performance of an edge in classic sharpness tests only has a loose correlation with how it performs in meat.

[@csquared4538]

I've been a sub for quite awhile. Stopped the knife hobby lately but you've been seriously crushing it with the conceptual videos. Really good stuff.

[@echos-myron]

I’m a Murray Carter sharpening method disciple; and it’s the most important thing in terms of how a knife performs that I learned from his fundamentals course. That and being able to put an edge on a knife using a cinderblock from the garden, river rocks, cardboard etc. Also, easily the hardest thing to explain to someone who’s unfamiliar with edged implements and how a good one should perform. You do a great job breaking the concept down in a way that’s easily understood as usual. ❤

[@BikingVikingHH]

What?

[@jez76]

👍🏼 I was thinking about Murrays video when I saw the apple cutting. How a dull edge crushes the cells in the apple leaving a sliced apple brown after a short while, while the apple cut with a sharp knife still looks fresh.

[@twatmunro]

Old Murray Carter was great. Modern Murray Carter who insists that you need to spend a fortune on his pal's extra special whetstones and thousand dollar flattening gear I'm not such a fan of. I miss the guy who did it all with a King 1000/6000 combi whetstone.

[@echos-myron]

@@jez76 when you show that to someone in person minds get blown; I like to do it a nice Onion especially. Murray’s shirts that said Stop Vegetable Abuse; Use Sharp Knives made me laugh every time I would see one. The Japanese masters have it dialed in to a degree that nobody else does in my opinion.

[@echos-myron]

@@twatmunro Fair point; Yeah I was a bit bummed when I saw those videos for the Nano Hone setup; and I’m sure they’re incredibly good stones; but Murray’s original thing was go buy this $30 king combo and get a bucket of water; setup complete; and it works very well. I don’t have a $1000 to put into that nano hone setup; and don’t need it to put edges on knives that freak people out; King and Naniwa budget stones produce those results.

[@TimJohnson-x1o]

great job. I've been trying to explain stuff like this to noob for ages. a well designed kitchen knife will continue to cut even when the edge is totally gone. it wont have "bite" or be able to do stuff like sushi chef whatever but for regular cutting, it will cut. it even can slice paper cleanly.. which some guys seem to think is an ultimate show of sharpness for some reason I can't understand. Yes, a well designed kitchen knife can be dulled on glass such that it wont even break skin and it can still cleanly slice paper like nothing. thats called geometry. So whats the edge for? cut intitation aka bite. try slicing paper towels with a dull vs sharp knife and you will see.

[@antouab221]

Man, I thought I'd see Clint Eastwood again, lol. The last video I watched was the one about steel rods and made me laugh all day, it was awesome (the duel in steel sharpening ). Keep up with these amazing video, I watch each and every one of them.

[@matthewcollinsangler]

Hey man, loving your work! The effort you put in and the lengths you go to to cover the subject of knife sharpness is insane! Keep up the good work. Regards, Matt.

[@robertdavis171]

I hate it when people say things like "5 times thinner" when they mean 1/5 as thick. What is 5 times less than 20? Well, 5 times 20 is 100. Is 5 times less than 20, -80? -100? 1/5 of 20 is 4, which is probably what someone means.

[@BirnieMac1]

I love the amount of information and the depth you go into the theory background of it all; great work mate

[@garywilliams4070]

I would really like to see you do a video that would recommend a good starting set of everything you would need to start your method of sharpening… and be very specific of exactly which products you would recommend. A complete starter kit ! Not necessarily the least expensive either… but products that would yield a beginner good results 😊

[@dragoscoco2173]

The cheapest 2$ scythe stone will do for the kitchen. Or 2$ worth of A4 sandpaper, one of 400grit and one of 800 if you feel fancy.

[@BuckShot-w4p]

Love your videos man keep up the good work

[@geraldposter1496]

Also there's some tasks we assume need a sharp edge, but don't. Like, at all. When I was working in a kitchen my favorite way to demonstrate this was to take a chef's knife, flip it around and half heartedly whack the back of the knife into a watermelon. I could usually get it around half of the way through it because - surprise! - watermelons are crazy easy to cut. Even better was we had nothing to sharpen knives with, could still cut damn near anything with our dull as all hell knives. Granted sharp knives make things way easier and I'll always prefer using one over something that's less a knife more a piece of metal pretending to be one, but even slicing tomatoes isn't hard once you get a few tricks down. I'm not saying this to say "LOL, knife sharpness doesn't matter". What I'm saying is we as a species have gotten by slicing food up perfectly fine for centuries with knives that were in all likelyhood not very sharp. Cause give someone a dull knife and if they need to use it to eat, they're gonna find a way to use it. So demonstrating knife sharpness by cutting food stuffs isn't a very good demonstration since 9/10 times technique matters way, WAY more than the sharpness of the actual knife. Or in other words, yeah cutting paper and whittling hair is way more impressive to me than slicing fruit or meat up and a better way to communicate sharpness than using it on a cucumber because I'll just look at someone doing that and go "I can literally do that with a knife that is so dull that to show how dull it was I started whacking and sawing myself in the neck with it to prove a point".

[@florin-titusniculescu5871]

what "helps" a lot of cheap blades is ... the cheap metal sheet they were made of , i.e. a thin sheet of an unevenly granulated alloy with brittle spots alternating with soft spots , that sort of material chips off when cutting harder stuff , thus giving a "sharp" feel because it develops a very thin sawtooth here and there , also responds well to the steel honing abomination , and people are very used to seeing the blade getting slimmer , just because that metal is so poor that it "sharpens" itself while cutting bone

[@kraftzion]

Excellent demonstration of the component of knife design nobody talks about! Everybody whittles hair or cuts paper which is useless without good geometry! Unless of course that is what you are using the knife for.

[@makeitbetter.1402]

I know you’re just trying to prove a point (and you’re doing a good job of it) but, I have a friend who teaches cooking classes. One of their classes is for kids and this kind of thing would make a huge difference for them. He’s expressed that so much of the class is spent on knife safety that it’s distracting for the kids to actually do the food prep. I’ll pass this along, it seems really relevant. Thanks for doing weird science!

[@hrnekbezucha]

Mind blown. Thanks for making this experiment. Makes me question everything I thought I knew

[@jeffreydawson4520]

You’ve been crushing it with your videos recently, not like you weren’t before as far as content, but the production quality has risen. Great stuff! Steve makes a helluva good knife, I’m looking forward to getting another one before too long!

[@anthonyelmore146]

This is a masterclass on sharpness, thank you.

[@TalRohan]

I have to say that dollar store knife seems like a really good safe option for a kitchen, especially where kids are involved. I would be very happy cooking with that knife. I iomiagine that knife would keep its working edge for a number of years to be honest. its the equivalent of Grannies favourite knife that worked as it is for years.

[@drewrinker2071]

Wow man, your content never ceases to amaze me, I'm always learning something new watching your channel and I really enjoy the content you put out there and how you can take a normal dollar tree knife, make it cut like a 100 dollar chef knife . I like the hat you break down the science of sharpness and put it in laymen's terms that anybody can understand. Keep up the awesome content my man.

[@samspade2104]

Another interesting video. Thank you. In case I haven't said this before, you are one of the most intelligent KZbin sharpener guys out there. I consider your channel invaluable. Again, many thanks.

[@OUTDOORS55]

I wouldn't say that, perhaps just the loudest 😉 Thanks for the comment really appreciate it 👊

[@bretbowman2007]

Which is why I've been using the same two Mac knives (scarcely ever sharpened) all of my life and I'm old now. The high carbon, chrome, vanadium, molybdenum and tungsten alloy, blades are super thin and relatively brittle but they slice through virtually all food with perfect ease.

[@olli_brb07]

I still think the best messuring tool for the sharpness of a kitchen knife is soft tomato. If it cuts the soft tomato without squishing it even a bit, it's probably sharp enough

[@hachi666roku]

I enjoyed this vid- because I have a Manix 2 I rescued and while it struggles to cut reciepts and paper towels, MAN does it glide through cardboard, plastics and other stuff around a warehouse. I also have a spyderco resilience 8cr13mov I use for food prep and not even hoagies can stop it. Light cut, gash in the cutting board 😂 geometry and secondary bevel

[@All_Things_Out_Doors]

Fantastic call out!!!

[@krazmokramer]

My mother was always afraid of cutting herself while cooking. I don't think she ever sharpened her knives. Yet she had no problem cutting food, just like in this video. I, on the other hand, spent 35 years using scalpels in my dental practice. I expect my EDC and kitchen knives to be nearly as sharp. Having watched your sharpening videos, I can say, and prove, that my knives are "surgical sharp." My current EDC is a Civivi Elementum Fixed in D2 ($80). I was told D2 is hard to get a sharp edge. Not true if you pay attention AND LEARN from these videos! THANKS for these videos!

[@Bob_Adkins]

I totally agree. Camping, chopping, batoning (argh!) are the only reason a knife needs a thick blade. I know many like the feel of a hefty blade in the kitchen, but they would be better off getting used to a thin blade that needs touching up only when ready to cut a roast into jerky or sausage. Add good steel, good sharpness, and a thin primary edge to the thin blade, and it.will.cut.

[@redrustyhill2]

Only dummies chop and baton with a knife, that's what machetes and axes are for. Knives are for CUTTING

[@LifeMyWay007]

I still like the idea of kitchen and table (food prep and steak knives) suggestion of at least what to look for if you don't want to get into specific suggestions. I know I need new knives/knives that work, but just for the average person who does Not need/want custom kitchen knives nor the expense of them. Something like the kitchen knife version of your Shapton Stone recommendation. I currently have no idea what to look for in kitchen knives, just that I need some. What do we look for that paired with the Shapton will comfortably (both in the hand using and cutting) last years/decades - without stressing out our wallet?

[@buckwheat7424]

i used to sharpen puddy knives to a apex sharp edge, and one day i realized that cutting it square works much better and more sturdy. holds the edge better, is easy to dress up, put in a vice and cutting along the edge with a large file instead of cross cutting it. keep the file square with it.

[@igordzuro4353]

You can really tell that whoever wrote that comment has 0 idea of how knives, cutting, geometry, mechanics and material physics work. Again, really great video showing off how different properties of a knife make it behave in different ways. Hopefully whoever watches this video gets a better understanding of how this actually works so they can put their tools to more effective use.

[@ennergie]

I have kitchen Knifes with en extremely thin geometry. Have not sharpened them in two years of nearly dayly use. They are still fine. For lazy people having thin knives is so mutch more usefull, than having sharp ones.

[@wolfingitdown2047]

This is what we (I) have all been waiting for!

[@LogisticallyMisrepresented]

All of this is what makes knives so alluring and irresistible 💙

[@Yupppi]

I feel like this video demonstrates the idea of sharpness and the thought how things often sit in the spectrum and what we perceive as binary conditions are often times just the same thing in a magnitude smaller. Like surface quality is still just mountains and valleys, just smaller than we can see with bare eyes. What I value in a sharp knife is the hair test type of quality: I don't need to use force or movement to cut, I just lay the edge on the target and it almost cuts itself. Because most of the risks at least for me come when I need to use force and movement. Soft or hard foods, I want the shape preserved and minimum force nad movement used. Maybe I'm still not right about the differences of geometry and the edge sharpness itself, but that's what I conceptualise as sharp knife.

[@ss181292]

As You said in previous video. What is sharp for one, may be completely dull for another. Maybe chefs consider knife sharp, what you consider dull. That's why they are using honing steel - to make dull knife a "sharp" enough for the task.

[@wsieber89]

The knife with the squared edge is genius. It can never go dull if its already dull. Hes cracked the code.

[@PhilippeCarphin]

Nice, as someone who is into knives I usually tell people "Most kitchen tasks can be accomplished with a thin piece of metal". With people who kinda know about knives I use that same phrase to drive home the importance of edge geometry. I was surprised with the performance though. Seem quite different from a "naturally occurring" completely dull knife. With a naturally occurring dull knife the not-an-apex is a lot smoother. Naturally occurring dull knives aren't likely to be super thin like yours. I'd be curious to see what happens if you were to polish that not-an-apex.

[@walkerscountrylife]

I think thats why a lot of people just dont 'get' knife sharpening. They think the knife is sharp when it isnt. Great demo, Im still very new to all this but weirdly sharpening axes has helped kme w lot with knives, and its a similar reason. How they perform is more due to geometry than sharpness.

[@fletchersreign1811]

This is a hilarious video after everything you've already done with the knife, really puts it into perspective how much people take things so seriously

[@ArneHB1]

Can you do a video for products you'd use to sharpen your blade in the field. As a hunter I can find my knife dull quicker when skinning and boning a animal. Products that are light weight, easy to use without having to rest them on a surface and easy to clean or not that sensitive to dirt

[@edubs9828]

Are you going to do a follow up video where you sharpen that knife?

[@OUTDOORS55]

It is sharp..im confused 🤔 😂

[@edubs9828]

@@OUTDOORS55 I dunno. Maybe you reinvent the wheel again and create a scalpel. lol