Hello Justin. I'm always trying to learn new things about sharpening so I love to see another perspective. I think maybe you will enjoy this long sharpening theory discussion. For blades that cut with impact a polished edge may increase edge durability since it has less fatigued metal and less points of fracture. Gabe from the Home Slice had an excellent experiment on it, and Cliff Stamp also recommended it. A high polish edge is also great for cutting paper, hair and raw meat but it tend to slip on other materials. Sometimes a coarse edge works better than a polished one despite the apex not being as fine and despite the subsurface metal fatique. For example if you cut rope a polished edge will not perform well nor last very long. Another example is barbecue crunchy fat layer, if you use polished edge it slips like crazy and a rough edge performs much better. In the kitchen polished edge tends to slip on tomato skin. Coarse edge has a thicker apex but if well sharpened it can shave hair even out of a 36 grit. I haven't tried that yet but I managed to shave badly out of a 120 grit silicon Carbide stone. That expected apex width rule from the book doesnt match my experience because that on a 120 grit stone the apex would be 12 micron and fully blunt. This sharp coarse edge cuts vegetables and barbecue very well but struggles with raw meat. For a general purpose knife I would rather finish somewhere between 1k and 6K. A Bess tester is interesting but its important to test your edges on the materials you will be cutting instead of just the Bess numbers. Sometimes numbers don't reflect reality, for example If you are using a cutting board and the knife has perfectly formed apex with 0.1 micron may be too thin to hold the edge. It will perform great on the Bess and then drop severely because the edge just rolled despite no Burr. A thicker edge that can just cut paper towel but no hair wittling may not perform as well before touching athe cutting board but may be strong enough to avoid rolling . Going down to 0.1 micron on soft steel is certainly a bad choice, on high hardness and high toughness steel its worth considering and experimenting. A Bess result before and after the first day of use seems like an interesting experiment. I still need to test hair whittling to get my own opinion on it. I heard that hair whittling doesnt last long so I only sharpen untill I can shave hair and cut paper towel. So far I like to pay more atention to edge geometry rather than just apex sharpness. For example most kitchen knifes with up to 60 HRC can't be sharpenned at 10 degrees but if you add a 15 degree microbevel even soft steel can hold the edge. This more acute edge will perform much better on hard vegetables like carot an onion.
I have a similar perspective & decided to develop testing equipment to test our concepts. I want real data from cutting real foods. I am currently testing to get a baseline for factory sharp 15º angle apex grinds. Currently comparing them to 15º micro-bevels with 8º grinds for secondary bevels 0.005" to 0.006" behind the d\secondary bevel. I will post a video with results.
@@danielbottner7700 This comment was from 2 years ago. I got some new experiments done after that. I tested hair whittling edge on a Din 1.4116 steel blade at 56 HRC. I didn't notice a significant cutting performance difference on food, probably most of the resistance comes from behind the edge. The edge didn't roll as I was expecting, It kept shaving sharp after the first day of use but on a single session it lost the hair whittling capacity and could not pass other hanging hair tests. Probably I should test it again on better quality steels but the results were so bad I gave up on it and now I only sharpen my knives until they can cut paper towels. I had much better results paying attention to edge geometry and surface adhesion. Edge geometry has a huge impact on cutting performance as you probably already noticed. Many people say you need a 20 degree large bevel on soft steel but that's not my experience at all. I sharpened a 54HRC knife at 5 degrees and finished with a double microbevel. 0.05mm at 15 degrees followed by 0.19 mm at 10 degrees. The thickness at 1 mm from the apex was 0.13 mm (0.005''). This could blade could push cut onion Brunoise without impact, something I had only seen on high end Japanese blades. Considering how thin it is I was already expect high cutting performance, but I was expecting low durability due to edge rolling or chipping. To my surprise this ultra thin geometry could withstand multiple moderate impact on the cutting board and still cut paper towels afterwards so now I don't expect any durability issues. Considering how little force I need to cut probably this will outlast a thick 15 degree edge on the same knife as long as I don't abuse it. I did this impact test to check for edge durability but I would not use it on impact knives or a carving knife that has to deal with lateral forces. The decision to leave a thick edge on European knives is a cultural choice and not a limitation of the steel type or hardness. That being said a 60-63 HRC knife would have much better edge durability. By your description what you did sounds pretty close to mine but we could have some measurement bias. For example my measurements with a cheap plastic caliper were very different from microscopy analysis. Microscopy not only is more precise but it also gives a better idea of what is going on. Another important point I learned was food adhesion. It happens due to capillary adhesion force. A polished Full Flat knife sticks to potato like crazy and has horrible cutting performance even if its cuts paper towels. A very subtle convex, hammered finish or embossed surface significantly reduce surface contact area and resistance by adhesion but its not enough to make the food fall off. An obvious convex will make food fall off but will create resistance because its thick so not ideal either. A subtle S grind Convex concave will do the trick without unnecessary resistance as well as my power drill grind lol. When you try food as performance you need to try what you cut more often but it's good practice to try onion Brunoise as its one of the harder tests for shoulder resistance. Carrot Brunoise is even harder but I skip this test because I never use it in practice. Potato is the best test I got for adhesion. Everything I mentioned is available in my channel but It's on Portuguese. If you want to watch it with subtitles and don't understand something feel free to ask me.
Very nice video explaining the issues of deburring and the different levels of burrs. I too sharpen my expensive kitchen knives using Shapton glass stones from 500 to 8000 grit, and now using Jende 1 micron and .25 micron strops at the end. I have noticed as you've said, that even when I've sharpened and thought that I've deburred the edge and done cut tests with soft paper, I've cut some veggies like carrots and celery, then noticed that my expensive Shun or my Bob Kramer 8" Chef Knife, suddenly didn't feel razor sharp anymore after just cutting some veggies. So, even if you can't feel a burr with your fingers, there can still be a foil burr on the edge that is not detectable by feel because it's sticking straight off the apex of the edge. That's why when you use your sharpness machine, the thread can fold over that foil and score that 150 or 200 sharpness. Getting rid of that imperceivable foil burr is so difficult. I've ordered an old-fashioned "Razor Strop" with linen on one of the strops to try and rid the "Foil Burr" before going onto my Jende 1 Micron and then .25 Micron diamond strops. I'm hoping that will be my ultimate solution to the "Foil Burr" issue with those of us that are seeking the ultimate sharpness. Lastly, even "Corks" or "De/burring foam squares" sold by sharpening suppliers, doesn't always work to get rid of that microscopic foil burr that can't be felt with even sensitive fingers. That's my two cents on this subject.
Tried this method on an endela 20cv. Only have 1.5 and 1.0 paste. Fantastic!! Have to be very careful to be able to whittle hair. To easy to just cut it. Just ordered .5 and .25 paste. I was very careful not to make a burr with strop. Never was very careful about that before. I was aware of it, but didn't believe it was that much of a problem. Wrong! Now I have to get the good Bess tester for xmas! Thanks alot! Love your videos!
Awesome! Drawing out a burr on a strop is something that never occurred to me until somewhat recently. I’ve been working on understanding it totally a lot lately but still not 100%.
I just tried this method on my Kurosaki senko bunka with SG2/R2 at 15°DPS with dmt stones started at 1,500 to get my apex and not remove a lot of steel then went to 2,000 and finished on 3,000 all dmt did light pressure edge trailing then leading and did that through each progression. I then stropped on 1µm Diamond emulsion on cow hide. Then raised the angle by half a degree and used .5µm Diamond emulsion on kangaroo. I stropped with mostly light pressure on the strops and finished with only 2 strops just as you said in this video the knife will push cut through paper and whittle hair. This is one of the best edges I’ve ever got. I think it’s sharper then how it came in the box. I will definitely keep using this method.
Very interesting & a great explanation . . . I learned a lot. - What's your perspective on steel plasticity introduced through sharpening ? - What's happening at the atomic levels within metallic particles ? - What's happen in the metallic crystal boundary areas ? All of these factors have the potential of reducing durability of the cutting edge. We know from past research that cracks form in the metallic structures: especially when sharpen on belt grinders. How can we avoid these forms of metal fatigue at of near the knife apex ? Appreciate any insights you have on these knives sharpening issues.
Very interesting. The more videos I see the more I know how much I have to learn. I'm going to experiment myself with the stropping techniques you've discussed here. I've found out thru the last year or so how much one can screw up a great edge by stropping too long. I've also learned how much you can improve and edge with stropping. It's definitely a double edged sword. (pun intended)
Very much so! I’d say I’ve gone more away from stropping now than ever! Often choosing to finish edge leading strokes on the stone only or just follow with 2-3 passes per side max
@@EngineersPerspective701 about the only stripping I do now is very very light passes and only very few, maybe 5 or 6 per side with 3micron or less paste on either dense leather or balsa wood. I find I don’t screw up as much that way.
You can use a bright led flashlight as this will highlight the burr really well. Also a knife that has any burr will absolutely not cut a paper towel or tissue, cleanly without catching the fibers, but a properly deburred knife will. Magazine paper or phone book paper is also good, but not fool proof. Jewelry loope is a good way to tell as others have said . I think a lot of ppl get frustrated with learning knife sharpening because most ppl starting out in the knife world will most likely be sharpening on D2 and D2 is awesome awesome steel. However it's not the best steel to learn deburring because it likes to hold on to that burr. Learn on 14c28n then try d2. Good Heat treat also helps. High angle, very low pressure, reverse passes on a 1500 - 2000 grit ceramic rod will cause your wire to fold over. Then you can sheer it clean after folding it 2 times on the rod by doing forward passes with the rod light pressure high angle
Whether or not the edge catches fibers can be a manner of edge finish too. Finishing on a 400 grit Naniwa whetstone produces a much less uniform edge than say, a Spyderco UF or a Venev F1200.
Your thoughts are definitely in the correct direction. I suggest You sharpen some 1095 carbon steel ( inexpensive experiment, ) and see how the burr removal is simplified. There is a difference in sharpening stones & sand paper in raised abrasive and buried abrasive. Raised abrasives are so much more aggressive. The size & shape of the abrasives determine the cut into the blade steel , causing stress , when a belt the speed cause friction that translates into heat that causes changes in the qualities of the steel integrity, the roots , like the roots of a tree ( you refered to ) are pronounced with ever spark that flys from the edge of a blade. With each valley carved out , gouged out , stresses are impacted in many deep directions . Chasing the Burr is not an elimination of the Burr a their steel or leather alien the Burr in a forward direction. I under stand there will always be a burr , by going to smaller & yet smaller abrasive size minimize the Burr . Jewelers often burnish gold to harden the surface , I would like Your thoughts on that possibly when getting a mirror finish on the edge ? ThIs are just thoughts and ideas . Great video , outstanding work.
I've sharpened a Mora, couple ESEEs, a GEC and a Case knife in 1095. Different experiences across them with different heat treats but overall I find that it's actually pretty hard to deburr without getting a completely smooth edge. Not a huge deal when processing wood IMO but not great for EDC in my book. Agreed that a burr is never really 100% removed in sharpening but it's not necessarily a function of abrasive size. With the right steel, heat treat, abrasive and technique a person can get an equally clean edge at 400 grit as 4000. It's just a lot more demanding on those 4 categories. As for burnishing, I do feel like it happens in sharpening. Especially with the higher grit stones which is why I am a huge believer in diamond, CBN strops and ideally finishing stones. Burnishing is just fatiguing the crap out of the apex. From others I've heard that ideally a person would switch to super abrasives around the 6um mark but honestly I still use 5K, 8K alumina stones anyway because I just enjoy them
Excellent! My two sharpening stones are the Venevs (240/400 & 800/1200) you used in your demonstration and I have the Gunny Juice. It really is helpful when you see good demonstrations with the equipment you're using. Thanks for the info!
I’m sort of coming to the same conclusions as you (longtime sharpener). I’ve realized how easy it is to smooth out the edge on strops, and try to be as clean as possible off the stones so I don’t have to strop as much. Getting a a super sharp smooth edge that whittles hair is no problem for me (which is fine for push cutting, wood processing knives). It’s getting a clean toothy edc edge that can be difficult. I will say that I’ve seen tests (mostly Cedric and Ada) that many polished edges seem to last longer than an aggressive edge. It seems the higher carbide steels generally do better with an aggressive edge, but science of sharps newest postings sort of suggest otherwise.
I never want to sacrifice cutting ability for hair whittling so that's always my battle. In my use, it seems like the higher carbide stuff cares a lot less about the edge finish in the long run. My theory is that as the edge wears down, there are so many carbides getting exposed at the edge that they both 1) significantly slow the apex width increase due to abrasion 2) Have little cutting faucets that significantly aid in slicing. Even with a very fine edge, they break down into a slicing machine anyway so it's really up to the user how they want to play the up front sharpness game.
Hey great video, do you by chance have access to a microscope? Some years back when I purchased my first microscope to examine edges that really opened my eyes as to what is going on with different stages of the sharpening process, really an invaluable tool in my opinion.
I have an inexpensive 120x one that I've used some but not in a while. I've had a number of comments about it so I think I really need to circle back. My memory of it is that it was difficult to see the final transition from tiny burr to clean edge but no doubt its something gained over time.
@@EngineersPerspective701 Nice, is it a USB type microscope? When you start getting into mid level and especially higher end microscopes you can actually see the micro chipping you talk about. A metallurgical microscope imo is the best for these close ups (since is projects light through the lens) and is what I use, also have a stereo microscope up to 90x that is extremely useful. When you get around 400x or so and up is when you really start to see what is going on.
@@NORTHWESTKNIFEGUY Mine is a Carson MicroBrite 60x-120x handheld for $16 on Amazon. It does have a light at the base so I can see edges decent but I think I'd need that 400x to take it to the next level as you've alluded too. Definitely can't swing a metallurgical one, the wife would put an end to me😅!
@@EngineersPerspective701 Yeah, it really makes a world of difference. If you keep an eye out on ebay for a nice used one you can save a lot over getting one new, run it by the boss and maybe she'll let you get one. :-) Also a cheaper compound microscope like swift, amscope etc. will normally work well too on the lower settings with an overhead light source like an led lamp shining down.
@@NORTHWESTKNIFEGUY ----- Microscopy is a science in and of itself. There are videos using microscopes at 400X+. I think one guy set up a metallurgical scope at 1200 or more, and resolution is as important as magnification. I have a USB set at 200X and I still don't know exactly what I'm looking at. I tried a $100 dollar metallurgical at 800X (trivial price compared to $10,000+) but it's such a tricky thing to focus .... At some point, I think one must imagine / picture what is going on and proceed with theory. To go to 2400X you're into lab science, properly prepared samples, oil immersion, polarized light ... not worth it!
Sorry if I make separate comments , but when you strop you just polish the micro/nano serrations , the result is so good it feel like a sharpening :) Like Shawn from Triple B said you need a good sharpening then stropping is the icing 😜
I want a totally sharp edge off the stone that gets cleaned up and magnified on the strops for sure! For many years I only ever looked for a bit of "icing" but right now I'm experimenting with doing real work on the strops and taking the edge to the next level.
@@EngineersPerspective701 The strop just enhances every grit. I've read that online long ago and that's true. Probably it's the gentleness of the leather compared to a stone. Even a 400 grit is cool with a strop pass 😳😀
@@dimmacommunication Definitely can be! For a long time my standard edge was a 600-700 grit diamond plate edge followed by 1um strop. Such a great cutter and a well done version of that edge is still my favorite of all time especially on something like 10V or K390 it is smokin!
Just came across this video of yours. Can't believe I missed it when it came out. Anyway, very interesting. Still seems like so many variables to take into account, especially when freehanding. Anecdotally, basically consistent with what you are saying, I have noticed that for me on most steel that 4 micron to 1 micron or 0.5 micron seems to work pretty good on strop progression. However, there are of course many combinations I haven't tried to compare to no doubt. Curious about that idea about knowing if the burr is there based on specified low BESS threshold score. Seem like you could have a dull/blunt edge with no burr but high BESS.
I think a lot of the variables are just getting used to your methods and the particular blade even anecdotally. What I will say has been frustrating me at the moment is with all types of steels and strops, I can generate new burr when stropping and it doesn't take that many strokes to do either. It seems like unless I'm either careful or highly intentional with my strop progression that I make the edge perform worse. The direction I'd like to go is lower grit compounds and just not overstrop, only used to "clean up" so to speak. Absolutely agree on the essentially blunt edge with low BESS score. Some of the sub 100g kitchen knives I've done have been DREADFUL in action. I did get a killer 70g on CTS-BD1N but the point is if BESS score is the only concern then it's easy to be lead astray.
@@EngineersPerspective701 this issue of forming a burr with stropping is interesting, I don't think I payed much attention to it before. I have always done alternating passes when stropping though so maybe that minimized burr formation anyway and it wasn't as much of an issue, I don't know. I am curious if you have noticed this to be dependent on the stropping medium at all? Also, was interested in your mentioning about microserrations. Guess you were referring basically to the effect you get with natural stones that I have heard of though I guess it is present to some degree with most sharpening. Would be curious to know more about this for sure. On a somewhat seperate note, you always hear about people bringing their dull edges back with some stropping. I have usually just done quick resharpening. I like sharpening anyway. Recently, however, I was playing around with stropping the edge back. Starting with the higher 16 micron compound then going to the lower microns seemed to work pretty good to get some bite back into the edge. With your talk of forming a burr with stropping it is now seeming to me that I was just basically doing a form of "mini" sharpening anyway with this stropping I guess 😄 Maybe I will purposely try forming burr as I would with regular sharpening just to see how it goes. As always, look forward to following your further elucidations on the sharpening process.
Isn't the fatigued steel zone work hardened and thus more resistant to wear? The theory is that fatigue creates dislocations. The burr/foil at the apex becomes so hard it breaks off.
I’ve done this with a Tojiro DP 170mm Santoku in VG-10 actually. Was the same knife but did it both ways on the chosera 3K. Results were that the edge leading felt toothy and scored around 130g BESS. Finishing with exclusive edge trailing felt more refined but the score didn’t actually change. The major difference was that the edge leading kept cutting for weeks whereas trailing needed to be worked on in a few days because the residual burr bent over. I may do a comparison using 2 fibrox knives for video
If you don't have a microscope, I'd recommend getting one. Even a cheap jeweler's loupe from Amazon can give you some additional, valuable feedback on your edges. Just a thought.
I have a 120x one that is just okay. I've used it some and it will reveal the cleanliness of an edge but not crazy useful. Honestly, I feel like if I used it more I could probably train my eye to see what I'm looking for.
Interested video,I use carson microscope to identificate and eliminate de burr,I dont use stone(natural or syntetic)to take it off..Do you recommend it me to incorporate on my deburring sequence? Regarda everybody
I am a big believer in doing as much deburring on the stone as possible before using a strop. But some steels and heat treatments are very forgiving and let you leave a larger burr and strop it off without loosing aggression and still getting a very clean, burr free edge. So in that case I am often lazy and will deburr less on the stone.
That's what I'm thinking. As of now, I'm not ready to believe that a sub 100 Bess edge is guaranteed burr free. I had some between 60-80 Bess that deteriorated very fast, after just a few cuts. Which wouldn't happen if I were actually cutting with a burr free apex.
I understand this concept and do believe there is something to it and it is one of the reasons I rarely ever sharpen on diamond plates. Especially course plates, they remove steel too quickly and the scratches they leave are too deep. Also I think edge leading strokes can be not so damaging to the apex as long as you use way less pressure than edge trailing. I rely a lot on edge leading for deburring a lot of steels but I use ultra light pressure when doing so. Excellent topic and video.
Science of sharp wrote an article on it specific to diamond plates which is where I first learned about it. The knife deburring book also discusses it but generally for any abrasive. I don’t think it can be avoided completely but it’s not a big deal really if followed up by strops to clean it up and refine a bit. In some ways I kind of actually like that nasty aggressive edge you can get from diamond plates when it’s been deburred and cleaned up properly. The best edge I’ve ever used was with 10V on a DMT fine followed by 1um diamond strop. That baby was hair whittling and so aggressive it blew my mind. Haven’t gone for that again in a long time but there’s something to be said for it!
👏👏👏 I said this exact same thing to jef jewell on Joe caltons last video. I'm using a 5 or I have a 7 micron then 1 then.5 raised 1 degree or so then bare leather a pass or 2. I've tried green to finish but I don't prefer that method freehand. The only .25 I have is from cktg I bought it awhile back but maybe I'll buy some gunny juice. And try that out!
I'd say if got this method pretty nailed down for steels like, Cruwear, LC200N, X50CrMoV15, CTS-BD1N and any that fall into or below this category for hardness/carbide volume. I've moved onto the higher carbide stuff, just K390 for now, and it does NOT like raised strops which is something I've found in the past. The point of this is to take the edge past my traditional single strop method and see what I get. We'll see what I find!
Deburring and stropping helps keep an edge sharp and durable longer ☝️ If you just sharpen a knife, notice why it dulls so fast like normies do with kitchen knives ☝️
Agreed. Science of sharp talks a lot about the mechanism that stropping creates a longer lasting and tougher edge right at the apex. I will say I can get very solid performance from a no strop sharpening specifically in kitchen knives. Not my go to but occasionally I’ll stop after a Shapton glass 8K with no strop or just strop on a dish towel
Stropping really makes a difference , makes you look like a weirdo compared to using a steel at home or elsewhere . People is used to see a steel not a strop
Pretty hard and not fast cutting. Decent feedback, better than the Shapton Pros by a lot. Leaves a really enjoyable finish and I really like the edge for kitchen tasks.
Very excellent question! I would say still hypothesis with some areas on the cusp of theory. Having confirmed mostly in the lower alloy and hardness sector. You’ve inspired me to correct the title, thank you!
@@EngineersPerspective701 I wrote it partly for fun and partly because most of population mixes these words up not knowing how are being used in science. That's why we often hear from ignorants evolution is "just"a theory...
@@dimatha7 that comment put a smile on my face so I appreciated it! Too bad the rampant lack of knowledge or wisdom of the general population isn’t equally entertaining. Alas life goes on!
All of this burr removal is predicated on your cutting stones being of diamond abrasives. Which means a total anihilation of the metal. That is correct for all diamond abrasives , no matter the particular size. Im wondering why all Japanese whetstone's are allways of a ceramic material. They seem to work very well. ln this discussion it a;; has to do with super abrasive /steel destructive diamond. Can you imagine using non diamond abrasive to sharpen, no matter what steel is is being sharpened. The belief is that diamond may be quick, but it also had its issues.
Sounds like you only have experience with diamond plates. Resin bonded or Super Vitrified diamond abrasives are head and shoulders above ceramics. You will get higher performance from them with any steel but it's extra pronounced with high VC steels. I love my ceramic Japanese stones too but diamond is the top dog
@@EngineersPerspective701 If you are referring to diamond plate , because of economics, then the durability, is very short lived. That is because of the diamond is rigid , in a metal structure. If you are referring to resin or vitrified diamond , then you are needing much higher speed or velocity of the surface. That equates tO a very different economic situation/ as long as you abrade with a fairly high micron or grit size of diamond. The purpose is for speed cutting/Finish should always be on a non cbn or diamond surface/ that is for durability of the metal apex.
I did forget a very important factor in the use of any diamond or cbn cutting abrasive. That is , the quality of manufacture of the final abrasive product. Accuracy of the actual size or grit, as well as the volume of abrasive .
Hello Justin. I'm always trying to learn new things about sharpening so I love to see another perspective. I think maybe you will enjoy this long sharpening theory discussion.
For blades that cut with impact a polished edge may increase edge durability since it has less fatigued metal and less points of fracture. Gabe from the Home Slice had an excellent experiment on it, and Cliff Stamp also recommended it.
A high polish edge is also great for cutting paper, hair and raw meat but it tend to slip on other materials.
Sometimes a coarse edge works better than a polished one despite the apex not being as fine and despite the subsurface metal fatique. For example if you cut rope a polished edge will not perform well nor last very long. Another example is barbecue crunchy fat layer, if you use polished edge it slips like crazy and a rough edge performs much better. In the kitchen polished edge tends to slip on tomato skin.
Coarse edge has a thicker apex but if well sharpened it can shave hair even out of a 36 grit. I haven't tried that yet but I managed to shave badly out of a 120 grit silicon Carbide stone. That expected apex width rule from the book doesnt match my experience because that on a 120 grit stone the apex would be 12 micron and fully blunt. This sharp coarse edge cuts vegetables and barbecue very well but struggles with raw meat. For a general purpose knife I would rather finish somewhere between 1k and 6K.
A Bess tester is interesting but its important to test your edges on the materials you will be cutting instead of just the Bess numbers. Sometimes numbers don't reflect reality, for example If you are using a cutting board and the knife has perfectly formed apex with 0.1 micron may be too thin to hold the edge. It will perform great on the Bess and then drop severely because the edge just rolled despite no Burr. A thicker edge that can just cut paper towel but no hair wittling may not perform as well before touching athe cutting board but may be strong enough to avoid rolling .
Going down to 0.1 micron on soft steel is certainly a bad choice, on high hardness and high toughness steel its worth considering and experimenting. A Bess result before and after the first day of use seems like an interesting experiment.
I still need to test hair whittling to get my own opinion on it. I heard that hair whittling doesnt last long so I only sharpen untill I can shave hair and cut paper towel. So far I like to pay more atention to edge geometry rather than just apex sharpness. For example most kitchen knifes with up to 60 HRC can't be sharpenned at 10 degrees but if you add a 15 degree microbevel even soft steel can hold the edge. This more acute edge will perform much better on hard vegetables like carot an onion.
I have a similar perspective & decided to develop testing equipment to test our concepts. I want real data from cutting real foods.
I am currently testing to get a baseline for factory sharp 15º angle apex grinds.
Currently comparing them to 15º micro-bevels with 8º grinds for secondary bevels 0.005" to 0.006" behind the d\secondary bevel.
I will post a video with results.
@@danielbottner7700 This comment was from 2 years ago. I got some new experiments done after that.
I tested hair whittling edge on a Din 1.4116 steel blade at 56 HRC. I didn't notice a significant cutting performance difference on food, probably most of the resistance comes from behind the edge. The edge didn't roll as I was expecting, It kept shaving sharp after the first day of use but on a single session it lost the hair whittling capacity and could not pass other hanging hair tests. Probably I should test it again on better quality steels but the results were so bad I gave up on it and now I only sharpen my knives until they can cut paper towels.
I had much better results paying attention to edge geometry and surface adhesion.
Edge geometry has a huge impact on cutting performance as you probably already noticed. Many people say you need a 20 degree large bevel on soft steel but that's not my experience at all.
I sharpened a 54HRC knife at 5 degrees and finished with a double microbevel. 0.05mm at 15 degrees followed by 0.19 mm at 10 degrees. The thickness at 1 mm from the apex was 0.13 mm (0.005''). This could blade could push cut onion Brunoise without impact, something I had only seen on high end Japanese blades. Considering how thin it is I was already expect high cutting performance, but I was expecting low durability due to edge rolling or chipping.
To my surprise this ultra thin geometry could withstand multiple moderate impact on the cutting board and still cut paper towels afterwards so now I don't expect any durability issues. Considering how little force I need to cut probably this will outlast a thick 15 degree edge on the same knife as long as I don't abuse it.
I did this impact test to check for edge durability but I would not use it on impact knives or a carving knife that has to deal with lateral forces.
The decision to leave a thick edge on European knives is a cultural choice and not a limitation of the steel type or hardness. That being said a 60-63 HRC knife would have much better edge durability.
By your description what you did sounds pretty close to mine but we could have some measurement bias. For example my measurements with a cheap plastic caliper were very different from microscopy analysis. Microscopy not only is more precise but it also gives a better idea of what is going on.
Another important point I learned was food adhesion. It happens due to capillary adhesion force. A polished Full Flat knife sticks to potato like crazy and has horrible cutting performance even if its cuts paper towels. A very subtle convex, hammered finish or embossed surface significantly reduce surface contact area and resistance by adhesion but its not enough to make the food fall off. An obvious convex will make food fall off but will create resistance because its thick so not ideal either. A subtle S grind Convex concave will do the trick without unnecessary resistance as well as my power drill grind lol.
When you try food as performance you need to try what you cut more often but it's good practice to try onion Brunoise as its one of the harder tests for shoulder resistance. Carrot Brunoise is even harder but I skip this test because I never use it in practice. Potato is the best test I got for adhesion.
Everything I mentioned is available in my channel but It's on Portuguese. If you want to watch it with subtitles and don't understand something feel free to ask me.
After 2 months I can say this is the best video about burr I've ever saw 💯
Awesome! Glad you liked it!
Very nice video explaining the issues of deburring and the different levels of burrs. I too sharpen my expensive kitchen knives using Shapton glass stones from 500 to 8000 grit, and now using Jende 1 micron and .25 micron strops at the end. I have noticed as you've said, that even when I've sharpened and thought that I've deburred the edge and done cut tests with soft paper, I've cut some veggies like carrots and celery, then noticed that my expensive Shun or my Bob Kramer 8" Chef Knife, suddenly didn't feel razor sharp anymore after just cutting some veggies. So, even if you can't feel a burr with your fingers, there can still be a foil burr on the edge that is not detectable by feel because it's sticking straight off the apex of the edge. That's why when you use your sharpness machine, the thread can fold over that foil and score that 150 or 200 sharpness. Getting rid of that imperceivable foil burr is so difficult. I've ordered an old-fashioned "Razor Strop" with linen on one of the strops to try and rid the "Foil Burr" before going onto my Jende 1 Micron and then .25 Micron diamond strops. I'm hoping that will be my ultimate solution to the "Foil Burr" issue with those of us that are seeking the ultimate sharpness. Lastly, even "Corks" or "De/burring foam squares" sold by sharpening suppliers, doesn't always work to get rid of that microscopic foil burr that can't be felt with even sensitive fingers. That's my two cents on this subject.
Tried this method on an endela 20cv. Only have 1.5 and 1.0 paste. Fantastic!! Have to be very careful to be able to whittle hair. To easy to just cut it. Just ordered .5 and .25 paste. I was very careful not to make a burr with strop. Never was very careful about that before. I was aware of it, but didn't believe it was that much of a problem. Wrong! Now I have to get the good Bess tester for xmas! Thanks alot! Love your videos!
Awesome! Drawing out a burr on a strop is something that never occurred to me until somewhat recently. I’ve been working on understanding it totally a lot lately but still not 100%.
I just tried this method on my Kurosaki senko bunka with SG2/R2 at 15°DPS with dmt stones started at 1,500 to get my apex and not remove a lot of steel then went to 2,000 and finished on 3,000 all dmt did light pressure edge trailing then leading and did that through each progression. I then stropped on 1µm Diamond emulsion on cow hide. Then raised the angle by half a degree and used .5µm Diamond emulsion on kangaroo. I stropped with mostly light pressure on the strops and finished with only 2 strops just as you said in this video the knife will push cut through paper and whittle hair. This is one of the best edges I’ve ever got. I think it’s sharper then how it came in the box. I will definitely keep using this method.
That's awesome! Hope it keeps performing well for you
Good discussion. Thanks for your thoughts on this. Well worth the watch and consideration.
Appreciate the comment!
This video has help me understand so much more about the burr and it's removal thank you so much
Glad you enjoyed it!
Very interesting & a great explanation . . . I learned a lot.
- What's your perspective on steel plasticity introduced through sharpening ?
- What's happening at the atomic levels within metallic particles ?
- What's happen in the metallic crystal boundary areas ?
All of these factors have the potential of reducing durability of the cutting edge.
We know from past research that cracks form in the metallic structures: especially when sharpen on belt grinders.
How can we avoid these forms of metal fatigue at of near the knife apex ?
Appreciate any insights you have on these knives sharpening issues.
Very interesting. The more videos I see the more I know how much I have to learn. I'm going to experiment myself with the stropping techniques you've discussed here. I've found out thru the last year or so how much one can screw up a great edge by stropping too long. I've also learned how much you can improve and edge with stropping. It's definitely a double edged sword. (pun intended)
Very much so! I’d say I’ve gone more away from stropping now than ever! Often choosing to finish edge leading strokes on the stone only or just follow with 2-3 passes per side max
@@EngineersPerspective701 about the only stripping I do now is very very light passes and only very few, maybe 5 or 6 per side with 3micron or less paste on either dense leather or balsa wood. I find I don’t screw up as much that way.
You can use a bright led flashlight as this will highlight the burr really well. Also a knife that has any burr will absolutely not cut a paper towel or tissue, cleanly without catching the fibers, but a properly deburred knife will. Magazine paper or phone book paper is also good, but not fool proof. Jewelry loope is a good way to tell as others have said . I think a lot of ppl get frustrated with learning knife sharpening because most ppl starting out in the knife world will most likely be sharpening on D2 and D2 is awesome awesome steel. However it's not the best steel to learn deburring because it likes to hold on to that burr. Learn on 14c28n then try d2. Good Heat treat also helps. High angle, very low pressure, reverse passes on a 1500 - 2000 grit ceramic rod will cause your wire to fold over. Then you can sheer it clean after folding it 2 times on the rod by doing forward passes with the rod light pressure high angle
Whether or not the edge catches fibers can be a manner of edge finish too. Finishing on a 400 grit Naniwa whetstone produces a much less uniform edge than say, a Spyderco UF or a Venev F1200.
Your thoughts are definitely in the correct direction. I suggest You sharpen some 1095 carbon steel ( inexpensive experiment, ) and see how the burr removal is simplified.
There is a difference in sharpening stones & sand paper in raised abrasive and buried abrasive. Raised abrasives are so much more aggressive. The size & shape of the abrasives determine the cut into the blade steel , causing stress , when a belt the speed cause friction that translates into heat that causes changes in the qualities of the steel integrity, the roots , like the roots of a tree ( you refered to ) are pronounced with ever spark that flys from the edge of a blade. With each valley carved out , gouged out , stresses are impacted in many deep directions .
Chasing the Burr is not an elimination of the Burr a their steel or leather alien the Burr in a forward direction. I under stand there will always be a burr , by going to smaller & yet smaller abrasive size minimize the Burr .
Jewelers often burnish gold to harden the surface , I would like Your thoughts on that possibly when getting a mirror finish on the edge ?
ThIs are just thoughts and ideas .
Great video , outstanding work.
I've sharpened a Mora, couple ESEEs, a GEC and a Case knife in 1095. Different experiences across them with different heat treats but overall I find that it's actually pretty hard to deburr without getting a completely smooth edge. Not a huge deal when processing wood IMO but not great for EDC in my book.
Agreed that a burr is never really 100% removed in sharpening but it's not necessarily a function of abrasive size. With the right steel, heat treat, abrasive and technique a person can get an equally clean edge at 400 grit as 4000. It's just a lot more demanding on those 4 categories.
As for burnishing, I do feel like it happens in sharpening. Especially with the higher grit stones which is why I am a huge believer in diamond, CBN strops and ideally finishing stones. Burnishing is just fatiguing the crap out of the apex. From others I've heard that ideally a person would switch to super abrasives around the 6um mark but honestly I still use 5K, 8K alumina stones anyway because I just enjoy them
Excellent! My two sharpening stones are the Venevs (240/400 & 800/1200) you used in your demonstration and I have the Gunny Juice. It really is helpful when you see good demonstrations with the equipment you're using. Thanks for the info!
They’re really really great stones, especially for the money. I agree, can’t have enough sharpening videos out there says me!
Thank you for the very detailed video, well done
You're welcome! Glad you enjoyed
I’m sort of coming to the same conclusions as you (longtime sharpener). I’ve realized how easy it is to smooth out the edge on strops, and try to be as clean as possible off the stones so I don’t have to strop as much.
Getting a a super sharp smooth edge that whittles hair is no problem for me (which is fine for push cutting, wood processing knives). It’s getting a clean toothy edc edge that can be difficult.
I will say that I’ve seen tests (mostly Cedric and Ada) that many polished edges seem to last longer than an aggressive edge. It seems the higher carbide steels generally do better with an aggressive edge, but science of sharps newest postings sort of suggest otherwise.
I never want to sacrifice cutting ability for hair whittling so that's always my battle.
In my use, it seems like the higher carbide stuff cares a lot less about the edge finish in the long run. My theory is that as the edge wears down, there are so many carbides getting exposed at the edge that they both 1) significantly slow the apex width increase due to abrasion 2) Have little cutting faucets that significantly aid in slicing.
Even with a very fine edge, they break down into a slicing machine anyway so it's really up to the user how they want to play the up front sharpness game.
I must have manifested this post, thank you
Lol, glad you found it!
Hey great video, do you by chance have access to a microscope? Some years back when I purchased my first microscope to examine edges that really opened my eyes as to what is going on with different stages of the sharpening process, really an invaluable tool in my opinion.
I have an inexpensive 120x one that I've used some but not in a while. I've had a number of comments about it so I think I really need to circle back.
My memory of it is that it was difficult to see the final transition from tiny burr to clean edge but no doubt its something gained over time.
@@EngineersPerspective701 Nice, is it a USB type microscope? When you start getting into mid level and especially higher end microscopes you can actually see the micro chipping you talk about. A metallurgical microscope imo is the best for these close ups (since is projects light through the lens) and is what I use, also have a stereo microscope up to 90x that is extremely useful. When you get around 400x or so and up is when you really start to see what is going on.
@@NORTHWESTKNIFEGUY Mine is a Carson MicroBrite 60x-120x handheld for $16 on Amazon. It does have a light at the base so I can see edges decent but I think I'd need that 400x to take it to the next level as you've alluded too. Definitely can't swing a metallurgical one, the wife would put an end to me😅!
@@EngineersPerspective701 Yeah, it really makes a world of difference. If you keep an eye out on ebay for a nice used one you can save a lot over getting one new, run it by the boss and maybe she'll let you get one. :-) Also a cheaper compound microscope like swift, amscope etc. will normally work well too on the lower settings with an overhead light source like an led lamp shining down.
@@NORTHWESTKNIFEGUY ----- Microscopy is a science in and of itself. There are videos using microscopes at 400X+. I think one guy set up a metallurgical scope at 1200 or more, and resolution is as important as magnification. I have a USB set at 200X and I still don't know exactly what I'm looking at. I tried a $100 dollar metallurgical at 800X (trivial price compared to $10,000+) but it's such a tricky thing to focus .... At some point, I think one must imagine / picture what is going on and proceed with theory. To go to 2400X you're into lab science, properly prepared samples, oil immersion, polarized light ... not worth it!
Sorry if I make separate comments , but when you strop you just polish the micro/nano serrations , the result is so good it feel like a sharpening :)
Like Shawn from Triple B said you need a good sharpening then stropping is the icing 😜
I want a totally sharp edge off the stone that gets cleaned up and magnified on the strops for sure! For many years I only ever looked for a bit of "icing" but right now I'm experimenting with doing real work on the strops and taking the edge to the next level.
@@EngineersPerspective701 The strop just enhances every grit.
I've read that online long ago and that's true.
Probably it's the gentleness of the leather compared to a stone.
Even a 400 grit is cool with a strop pass 😳😀
@@dimmacommunication Definitely can be! For a long time my standard edge was a 600-700 grit diamond plate edge followed by 1um strop. Such a great cutter and a well done version of that edge is still my favorite of all time especially on something like 10V or K390 it is smokin!
Just came across this video of yours. Can't believe I missed it when it came out. Anyway, very interesting. Still seems like so many variables to take into account, especially when freehanding. Anecdotally, basically consistent with what you are saying, I have noticed that for me on most steel that 4 micron to 1 micron or 0.5 micron seems to work pretty good on strop progression. However, there are of course many combinations I haven't tried to compare to no doubt. Curious about that idea about knowing if the burr is there based on specified low BESS threshold score. Seem like you could have a dull/blunt edge with no burr but high BESS.
I think a lot of the variables are just getting used to your methods and the particular blade even anecdotally.
What I will say has been frustrating me at the moment is with all types of steels and strops, I can generate new burr when stropping and it doesn't take that many strokes to do either. It seems like unless I'm either careful or highly intentional with my strop progression that I make the edge perform worse. The direction I'd like to go is lower grit compounds and just not overstrop, only used to "clean up" so to speak.
Absolutely agree on the essentially blunt edge with low BESS score. Some of the sub 100g kitchen knives I've done have been DREADFUL in action. I did get a killer 70g on CTS-BD1N but the point is if BESS score is the only concern then it's easy to be lead astray.
@@EngineersPerspective701 this issue of forming a burr with stropping is interesting, I don't think I payed much attention to it before. I have always done alternating passes when stropping though so maybe that minimized burr formation anyway and it wasn't as much of an issue, I don't know. I am curious if you have noticed this to be dependent on the stropping medium at all?
Also, was interested in your mentioning about microserrations. Guess you were referring basically to the effect you get with natural stones that I have heard of though I guess it is present to some degree with most sharpening. Would be curious to know more about this for sure.
On a somewhat seperate note, you always hear about people bringing their dull edges back with some stropping. I have usually just done quick resharpening. I like sharpening anyway. Recently, however, I was playing around with stropping the edge back. Starting with the higher 16 micron compound then going to the lower microns seemed to work pretty good to get some bite back into the edge. With your talk of forming a burr with stropping it is now seeming to me that I was just basically doing a form of "mini" sharpening anyway with this stropping I guess 😄 Maybe I will purposely try forming burr as I would with regular sharpening just to see how it goes.
As always, look forward to following your further elucidations on the sharpening process.
Isn't the fatigued steel zone work hardened and thus more resistant to wear? The theory is that fatigue creates dislocations. The burr/foil at the apex becomes so hard it breaks off.
Late to the party
But great video Justin.
Appreciate your journey and candid reasoning.
Appreciate the comment!
You should get 2 of the same exact knife and do edge leading for one and edge trailing for the other. Then compare results. 😬
I’ve done this with a Tojiro DP 170mm Santoku in VG-10 actually. Was the same knife but did it both ways on the chosera 3K. Results were that the edge leading felt toothy and scored around 130g BESS. Finishing with exclusive edge trailing felt more refined but the score didn’t actually change.
The major difference was that the edge leading kept cutting for weeks whereas trailing needed to be worked on in a few days because the residual burr bent over.
I may do a comparison using 2 fibrox knives for video
Great info keep up the good work
Thank you!
If you don't have a microscope, I'd recommend getting one. Even a cheap jeweler's loupe from Amazon can give you some additional, valuable feedback on your edges. Just a thought.
True, always tought that.
Unless you see it clearly it's difficult to tell.
But I've already bought too much " geeky " stuff 😂
I have a 120x one that is just okay. I've used it some and it will reveal the cleanliness of an edge but not crazy useful. Honestly, I feel like if I used it more I could probably train my eye to see what I'm looking for.
@@EngineersPerspective701 I have one, and I have learned so much by including it in my sharpening feedback loop.
@@ZPositive totally! I’ve been using my Bess tester in much the same way but I should revisit it and add another data point!
@@EngineersPerspective701 I've been considering getting a Bess tester for the same reason. Which sampling rate does yours have?
Interested video,I use carson microscope to identificate and eliminate de burr,I dont use stone(natural or syntetic)to take it off..Do you recommend it me to incorporate on my deburring sequence?
Regarda everybody
I am a big believer in doing as much deburring on the stone as possible before using a strop.
But some steels and heat treatments are very forgiving and let you leave a larger burr and strop it off without loosing aggression and still getting a very clean, burr free edge. So in that case I am often lazy and will deburr less on the stone.
A $12 plastic microscope is pretty good way to detect burrs.
I see a Bess tester in my future.. Great video!
They’re very useful! Can be frustrating too lol!
Can I know the name what you use to look at the cutting pressure?
It’s the “Edge on up BESS tester”
I'm almost sure you could get a keen sturdy burr to score under 100 BESS. Albeit at that point, does it even matter?
That's what I'm thinking. As of now, I'm not ready to believe that a sub 100 Bess edge is guaranteed burr free. I had some between 60-80 Bess that deteriorated very fast, after just a few cuts. Which wouldn't happen if I were actually cutting with a burr free apex.
Well said
Thanks!
I understand this concept and do believe there is something to it and it is one of the reasons I rarely ever sharpen on diamond plates.
Especially course plates, they remove steel too quickly and the scratches they leave are too deep.
Also I think edge leading strokes can be not so damaging to the apex as long as you use way less pressure than edge trailing.
I rely a lot on edge leading for deburring a lot of steels but I use ultra light pressure when doing so.
Excellent topic and video.
Science of sharp wrote an article on it specific to diamond plates which is where I first learned about it. The knife deburring book also discusses it but generally for any abrasive. I don’t think it can be avoided completely but it’s not a big deal really if followed up by strops to clean it up and refine a bit.
In some ways I kind of actually like that nasty aggressive edge you can get from diamond plates when it’s been deburred and cleaned up properly. The best edge I’ve ever used was with 10V on a DMT fine followed by 1um diamond strop. That baby was hair whittling and so aggressive it blew my mind. Haven’t gone for that again in a long time but there’s something to be said for it!
helpful video to watch so one can go to bed
Glad my monotone can soothe you to sleep!
👏👏👏 I said this exact same thing to jef jewell on Joe caltons last video. I'm using a 5 or I have a 7 micron then 1 then.5 raised 1 degree or so then bare leather a pass or 2. I've tried green to finish but I don't prefer that method freehand. The only .25 I have is from cktg I bought it awhile back but maybe I'll buy some gunny juice. And try that out!
I'd say if got this method pretty nailed down for steels like, Cruwear, LC200N, X50CrMoV15, CTS-BD1N and any that fall into or below this category for hardness/carbide volume.
I've moved onto the higher carbide stuff, just K390 for now, and it does NOT like raised strops which is something I've found in the past. The point of this is to take the edge past my traditional single strop method and see what I get. We'll see what I find!
Also I have the 0.25um from CKTG also but it is clumped up BAD in the bottle. Basically unusable and I haven’t thought about what to do with it yet!
Deburring and stropping helps keep an edge sharp and durable longer ☝️ If you just sharpen a knife, notice why it dulls so fast like normies do with kitchen knives ☝️
Agreed. Science of sharp talks a lot about the mechanism that stropping creates a longer lasting and tougher edge right at the apex.
I will say I can get very solid performance from a no strop sharpening specifically in kitchen knives. Not my go to but occasionally I’ll stop after a Shapton glass 8K with no strop or just strop on a dish towel
🤠👍
😎
What do you use to remove the burr ? a soft wood ?
My goal for a great edge is to remove 95% of the burr on the stone. Then clean it up the rest of the way on the strops.
@@EngineersPerspective701 I've seen so many videos about sharpening in 6 years that I ended up doing what I always did lol
@@dimmacommunication No “right” way! Just what works for you and gives the results you’re looking for!
Stropping really makes a difference , makes you look like a weirdo compared to using a steel at home or elsewhere .
People is used to see a steel not a strop
It certainly does and in this community it's the expectation! But so very few people that I actually interact with in "real life" have a clue
@@EngineersPerspective701 People only know about it looking at old barber shop in movies or photos :)
Cut the waffle!
🔪🧇
It's missing engineering proof even at the excuse, that's a theory. As an engineer you've to give more than a speech
Pretty hard and not fast cutting. Decent feedback, better than the Shapton Pros by a lot. Leaves a really enjoyable finish and I really like the edge for kitchen tasks.
Theory or hypothesis?
Very excellent question! I would say still hypothesis with some areas on the cusp of theory. Having confirmed mostly in the lower alloy and hardness sector.
You’ve inspired me to correct the title, thank you!
@@EngineersPerspective701 I wrote it partly for fun and partly because most of population mixes these words up not knowing how are being used in science.
That's why we often hear from ignorants evolution is "just"a theory...
@@dimatha7 that comment put a smile on my face so I appreciated it!
Too bad the rampant lack of knowledge or wisdom of the general population isn’t equally entertaining. Alas life goes on!
All of this burr removal is predicated on your cutting stones being of diamond abrasives. Which means a total anihilation of the metal. That is correct for all diamond abrasives , no matter the particular size. Im wondering why all Japanese whetstone's are allways of a ceramic material. They seem to work very well. ln this discussion it a;; has to do with super abrasive /steel destructive diamond. Can you imagine using non diamond abrasive to sharpen, no matter what steel is is being sharpened.
The belief is that diamond may be quick, but it also had its issues.
There is nothing wrong with Diamond
You must love toothy edges/ don't care about the durability that diamond abrasives , lack.
Sounds like you only have experience with diamond plates. Resin bonded or Super Vitrified diamond abrasives are head and shoulders above ceramics. You will get higher performance from them with any steel but it's extra pronounced with high VC steels. I love my ceramic Japanese stones too but diamond is the top dog
@@EngineersPerspective701
If you are referring to diamond plate , because of economics, then the durability, is very short lived. That is because of the diamond is rigid , in a metal structure. If you are referring to resin or vitrified diamond , then you are needing much higher speed or velocity of the surface. That equates tO a very different economic situation/ as long as you abrade with a fairly high micron or grit size of diamond. The purpose is for speed cutting/Finish should always be on a non cbn or diamond surface/ that is for durability of the metal apex.
I did forget a very important factor in the use of any diamond or cbn cutting abrasive. That is , the quality of manufacture of the final abrasive product.
Accuracy of the actual size or grit, as well as the volume of abrasive .