Probably the best value for a good sharpening stone right now⬇ amzn.to/3fUilj5 Or my website www.outdoors55.com/shop where I go over knife sharpening stones / equipment, knives, and knife making equipment I have personally used and reviewed. As an Amazon associate I earn from qualifying purchases.
Yes, Unfortunately the only thing i can do is block them but then 3 more appear. Sorry I dont do giveaways. You can pretty much count on the fact that no TH-camr is doing giveaways in the comments. Thats not how anyone would contact you for a giveaway. I would think 99.99% of people would know this by now.
I would like to see a real time - no cuts sharpening video. Your videos always get a like from me. Thanks for breaking this down into crayons for me & anyone else that watches.
I can see why the explaining of that felt odd but I think you hit the nail right on the head. The big takeaway is that there is a geometry for each use case. Cutting soft veggies - a thin thin edge has a load of benefits. On the other extreme is the battoning you mentioned and that definitely requires a heavy edge if you want the blade to survive. We need more of these education videos in the community, thanks.
@@redrustyhill2I get what you’re saying which is why I’ve always used a hatchet. My guess is that when people baton with a knife is because they don’t want to carry around a hatchet when out bushcrafting 🤷♂️
@taylorbrandon86 any real "bushcrafter" will have the proper tools for the job. This whole "survival" nonsense stems from these stupid reality "survival" shows, thinking they will build a shelter and traps with nothing but a belt knife.
True of s110v. Heat treat and steel selection could also help limit chipping in that situation. But still holds true what you've demonstrated, just takes more force. Thats why when we buy thin knives we should know how to use them. Thats why some makers talk to customers to make sure they understand this and to not cut any hard materials with the super thin geometry. I have a playl-ist section on my page for geometry for more on the subject, I think I'll add this one to the mix. Check out the others too.
This may be the first time in a couple of years of delving into this stuff that I'm hearing a person say there was a potential price to be paid in thinning a knife. Yes, it's often said you don't want to have an edge angle so acute the metal can't support it. But thinning behind the edge? No warnings ever that I can recall. So this is next-level understanding, as usual. Thanks and keep it coming.
I have many different knives and they all have a specific purpose. They're all sharp and do whatever they were created for very well. Not to say that I've never chopped onions with my pocket knife because I have. My dad was a butcher and he had knives for everything and they were good knives. He died when I was 18 years old in 1971 but he told my mother to be sure that I got them. I cherish them and still remember how he showed me to clean them, store them and to keep an edge on them. I think some sharpening techniques I've learned from you and others are better techniques (Sorry Pop!) and the stones we have available today are certainly better than was available to him! But he told me something one time that I've never forgotten. He said: "Son, it's just as easy to carry a sharp knife as it is a dull knife". My pocket knife back when I was a kid was normally dull, very dull. But when you're a kid you're busy playing and I used that poor knife for every kind of tool when I was working on my bike or something else. He always gave me a hard time about not keeping it sharp. I keep it sharp now and never use it for a pry bar! When I think back on my life back then I feel kind of cheated that I didn't get to spend more years with him. After all of these years I still miss the hell out of him. Anyway, enough sadness. I'm happy to see that you're back and posting on a kind of regular basis again. You're my favorite knife channel and hopefully with more room now you may even build another knife from time to time. Thanks for the video!
Great video. Shows well pros and cons of a thin geometry. AEB-L probably would not chip with the same thin geometry. Clean carbides, high hardness potential and high toughness. That's why I think AEB-L is such a good steel. Cheap to make and outperforms several super steels in many tasks. To cut highly abrasive materials powder metallurgy still shines.
@@NSW15355 True. If you want to optimize for slicing AEB-L has higher toughness on 64 HRC than 1.4116 on 57HRC. If you want to optimize for toughness it gets four times tougher than 1095 on same hardness while also being stainless. It's a freaking beast but unfortunately it doesn't get top grade heat treatment from pretty much any of the large companies.
@@thiago.assumpcao aebl has history too. I think it was deployed in the 1950s as a razor blade steel for shaving. I was always drawn to it's ability to remain stable with a thin cross section and fine grain. And being stainless is nice
In solid mechanics, a stress concentration (also called a stress raiser or a stress riser) is a location in an object where the stress is significantly greater than the surrounding region. Stress concentrations occur when there are irregularities in the geometry or material of a structural component that cause an interruption to the flow of stress. Wondering if you can round the part where the edge and the blade meet.
That's how I sharpen my chisels. Can't say with any scientific certainty but it does feel resiliant and stronger edit: and very seldom get chips in the blades.
This is the correct explanation as far as I'm aware as material scientist. At the same time the procedure of thinning the blade without proper heat treatments in between and at the end could have weakened the steel a lot (initiation and lengthening of cracks). Grinding the steel puts a lot of plastic deformation in the steel which needs to be removed regularly.
As someone who has basically no real experience or knowledge regarding knives or steels in general I suspect the blade would just chip at a more random spot along the curve.
In my experience, stress concentrators mostly occur if the sharp corner is to the inside of the part, like a scratch(or a bigger similar geometry). Rounding the part where the blade meeds the edge might still help with the resistance by making the whole area more elastic.
The fundamental factor at play here is anisotropy. In the thicker blade more of the material immediately adjoining the break site is being supported along stronger axes. You could go more into depth in terms of crystal structure/boundaries, but it all boils down to the same thing.
Love this video. Kind of a surprise attack, I thought you were gonna recommend we all grind to .008" behind the blade. And then you gave us the, "But wait, there's more." The ideal behind-the-blade thickness is probably (entirely) task oriented. In kitchen knives, for example, guess I'd love to have a whole block of chef's knives with slots marked, .008 (maybe for sushi fish), .016 (boneless steaks), .024 (soft vegetables), .030 (carrots and potatoes). Chuckling...thanks for passing along your experiences and research.
Excellent job explaining and showing why the chipping occurred. Great job! Been a sub for a few years and your video style as well as all the info you give is why I still watch. Education and information 👊🏽
I'm a mechanical engineer. My intuition is that your explanation is correct. You also briefly mentioned stress risers, and I think that is also relevant. It would be interesting to model a few knife edges and do finite element analysis to try to backup or disprove these ideas.
I'd etch it and micrograph it at the chip site and along the now stressed edge. I'm thinking it's grain and grain support failure in this specific failure mode.
Hollow grinding has been the industry standard for most knives for a long time, except for the Nordic countries where we use "Scandi grind" (although I think it's a bad term since Finland is not in Scandinavia, and is a very important country in Nordic knife culture). Scandi grind leaves more material behind the apex, while keeping the blade thin.
I had a benchmade that I ground out to a long secondary bevel and a thinner primary. The steel was S30V. The edge literally flaked and crumbed from skinning some electrical wire for a splice. Prior to the sharpening, I could nearly baton the blade through a bundle of wire with no discernible damage. Great video and explanation. I’m wondering if steel type matters here as well? I’ve heard S30V is prone to flaking.
8:19 I could be wrong but i don't think it's really the size behind the sharp edge that make the apex strong. What i think happen is as you put your blade deeper into any item, the sides help cut by spreading out whatever items you are cutting through, therefor reducing the load on the tips. (It could also be a mix of what i just said and what you said at :19.. :) ) When you use an axe to chop in half a log, the sharp edge beging the work, and the thicker sides continue the harder work. You would not be able to split a log in half with only the thickness of the sharp axe edge using the same amount of force and head weight.
Definitely a great video. That's one thing that definitely matters a lot. Also like you said at the end, the task the knife is intended for, the hardness, the carbide volume (also carbide size to some degree), all matter a lot too. Especially when getting down to those thinness'. Something that's able to maintain good toughness, high hardness, while having just the right volume of small carbides, tends to do very well with thin grinds. Though even low toughness, higher hardness, and higher carbide steels can Excell, if the tasks theyre used for, don't involve impacts, or torquing the edge.
So something you should try doing is create a micro bevel with the 8 thou blade and compare it to something similar with a 30 thou blade and no microbevel. that would be interesting to see. keep it up!
I have 2 SAK knives with 2 different blade thicknesses. One is an officer model with a master blade for an 84 mm knife and the second is a 93 mm blade that is thicker. I like to get them to shave arm hair without pulling. The smaller knife achieves this much easier and quicker than the larger knife meant for heavier work. This video confirms why some knives have always been harder to achieve this level of sharpness as well. I have had several knives in the past from major manufactures, where certain knives sharpened easier and better than others of the same make or model. I always thought it was my inability but now I think it had to do with geometry too. Thank you for this great informative video! Jeff
This video came at the perfect moment: Just had chipping issue with one of my whittling knives which I thinned down. Thought it would cut wood like butter, but ended up chipping and making ugly scratches in the wood. Thanks for explaining. I’m working on restoring it now. Gently, because the blade of a detail whittling knife is not very high. Keep up the good work 😀👍🏻
For metal stability, it helps to draw in the force lines. This tells us, that rounding the edges between the triangle and the parallel surfaces can help to reduce the stress in the edges
I noticed the strokes weren't very smooth. I figured it was dull, but when you rubbed your hand on the blade, I was genuinely confused. I didn't think it was THAT dull.
Well done and very informative. I now have two related questions: 1) is there an optimal blade thickness for a given secondary bevel angle? and 2) is your Manix blade now ruined? How would you fix that?
No, it would depend on the end use of the knife. The manix ist ruined at all. Its thinner but I brought the bevel back and that added a couple thousands. Im working on a video showing me fix it.👍
Your demonstration with the cardboard cutouts was ingenious in its simplicity!!! ...who didn't understand that should stick to spoons rather than knives.
Nice Video very informative especially the demo about the knife geometry /angle when you showed the wood triangle comparison very impressive your'e the only person who showed something like that ..Thank you for sharing .👏👍🏼
Would you try a convex edge on your .008“ Manix? I think it would eliminate the chipping because it’s more „natural“ ( less hard edges ) edge. Nice video! Take care!
Excellent, as usual. I doubt that many people have the power tools to reshape the primary bevel. I think that I will concentrate on my basic technique.
Very nice simplification in my mind. It is good enough to be useful. And I think it holds up in predictions well enough compared to going much further -- like thinking about why the "all this supporting material" is supporting in the first place.
10:20 the force is actually along the entirety of the side of the primary bevel, except in cases where you are purposefully pushing the blade in sideways. It’s just that the pressure is too large for even that area. If it was only on that point, then it would deform first (flattening out) becoming a new secondary bevel which would then break off. While the model is somewhat rudimentary and can’t completely describe the nuances of metallic deformation, it’s pretty close if you only consider the sides of the triangle instead of that point.
It has to do with hardness and flex. Your blade is a material that has a higher hardness value but you thinned the blade to the point where there's not enough supporting material to resist the edge from flexing beyond the fail point and the hardness alone isn't enough to prevent the edge from flexing during normal operation.
Thanks for sharing! I learned a lot! Since the weak point of the edge is the pointed shoulder of the apex (possibly due to the abrupt change in angle on a microscopic scale between the primary bevel and secondary bevel), what if you were to round or convex the shoulder? Could that increase the strength of the edge? Just a thought.
great vid! you may even say steel typeband heat treat are serve to allow a specific geometry. Usage dictates geometry and thus dictates steel typeand heat treat
Really enjoyed the video, yet I believe you missed something: steels like s110v have an high volume of carbides, those can be either alone but are usually distributed in relatively small clusters, sized if I remember correctly in the range of 10 to 20 microns, those groups of carbides in very thin edge configurations may not be properly supported by the steel matrix, causing small edge blowouts. Finer grained, less carbide heavy steels may perform better: my spyderco chaparral right now is 7-10 tho bte, yet shows no significant chipping, even in rough cutting like chest-lever cuts on branches and whatnot Something like for example your 1084 should have nicer properties for that kind of edge imo Keep up with content, your channel is great!
Im not sure thats the case here due to where the chips propagated, which was right at the corner of the secondary bevel. Id lean more towards carbide if it was more towards the apex. Very good thought 👍
You should try sharpening at a more acute angle since the blade is now thinner, it sounds counterintuitive but it absolutely *could* be the reason for the chippiness Fantastic video btw!
I have been wondering for the last week: Why can't I get a cheap chef knife with super steel as a backup survival knife? Well, 11:19 was what I needed. ;) I should have known this since I grew up in the house of a knifemaker, but It never made sense until this video. Thank you for sharing your knowledge.
Please make real time sharpening video for that Manix 2 because I have the same and it is new so I dont have any experience with sharpening s110V! Thanks in advance
I'm convinced (science, it's like magic,but it's REAL). Finally, someone who knows what makes a good blade. I'm gonna be a loyal subscriber, keep it up.
So in your opinion, if you could choose, what steel or steels would be tough enough to not chip at 8 th behind the edge, and in hindsight would you now go for 10 thou bte for more compromise of slicing and toughness??
I have had this issue before with a victorinox boning knife. I had to increase my sharpening angle before it stopped chipping. I think i set the angle to about 22° till i had a edge that seemed usable. Where my thicker santoku knife will handle 17° no problem.
Sure that could be a technicality but when a blade is tempered it is heated to red hot temperatures. If the edge was that hot then the sandpaper would've caught fire and the rest of the blade would've been too hot to hold. Tempering should not be a concern when sharpening.
@@Demogorgon000nonsense. Heat treatment or temper, can be lost at well below red hot. Its very easy to quickly destroy a tempered blade with power tools.
just a thought copper wire is soft and sticky . you may have put the apex in a vise , with some off center pressure ..cut strait down to a surface maybe no problem please your thoughts
Geometry definitely cuts. I bought a Robert Herder paring knife and it was 2-3 thou tops(it's pretty much a zero ffg grind with a microbevel put on) and 44 thou blade stock and even it was dull from factory it cut cardboard almost as well as my razor sharp pm2 regrind to 0.005. After I actually sharpened it is the best light to medium duty cutter I've experienced. Not every knife needs to be 5-10 thou bte but for certain ones it is really nice.
I have the exact same pair of calipers. Mine were in the case on my night stand next to me I pulled em out to make sure lol. I have another pair from Clockwise Tools that I prefer. Gives regular metric and imperial but also fractions so if somethings 3/8 I don't need to look at a chart. Also bigger screen which I friggen love. $25 on Amazon
One of the best knife sharpeners ive ever come across had a surprising source. It was the arc tube out of a bad sodium vapor lamp. It would put a super sharp edge on almost anything 🤓😁❤
I would be interested to see whether the knife could have survived those tasks if it did not have a secondary bevel. I have a few knives that I have sharpened to that thinness, but I did not intentionally add a bevel. They may have a microbevel since hand sharpening isn't very precise. I haven't had any chipping or rolling yet but the steels are not comparable. Mine are 4116, 12C27N and 14C28N. I'm not about to risk my Maxamet Manix like that.
Sorry if i didn't see this in the comments, does anyone know if blade/edge stiffness plays into this? Does the thinner support material tend to flex and let the edge go wobbly in a way that could allow chips to pop off?
i love the beard and also welcome back and thanks for the video i learned alot i hope you talk more about carbides i read so many articles on knife steel nerds
I know this is an old video, but can you do testing to see what thickness is the best for cutting while reducing the chance of chipping? Would the thickness of a utility blade be the best, or should it be thicker than that?
What about a video where you improve the geometry of kitchen knives? What are some tools that you can use at homes? Maybe a deep dive into products on the market which have better geometry than the rest?
I suspect it has more to do with the change in angle at the bottom of the apex causing a stress concentration at that point, making it the point most vulnerable to chipping... which is why it tends to break there and not above or below. It's just that a full thickness blade has enough material at this vulnerable spot to prevent this failure mode under reasonable/normal use.
And you didn't loose the temperament of the steel by heating up the steel from grinding it down ? Or made it chippy by getting it hot. Then cooling it down rapidly ?
Since I am a stonemason, the image at 14:00 elicits a different impression. It reminds me of a stone edge when struct laterally by my hammer. Perhaps the little bumps of the sharpening media contacting the material at speed at that specific part of the blade produce unrecognized impacts. In the thicker blade, that same spot experiences zero impacts.
Great video, welcome back. Given that video can you give some suggestions for great geometry blades? I love my 940 but not the best slicer. Just a couple of your favorite folders. Any others than Manix?
This reminds me so much of those scored "snap" utility blades, where you just break off the section that becomes dull. Its a common occurence to experience chipping like this in my profession (mechanic, we use razors all the time) and razors chip right at the very apex often, but we also break them regularly because they are flimsy little pieces of metal (so is a bullet, but thats a different topic lol🤣).
Always look forward to and enjoy your videos. Thanks for the time you put into this. There isn't a ton of TH-cam videos focusing on geometry, toughness, and heat treating so that information is much appreciated.
I think you should consider how the chipping occurs. Presuming it's side load, leverage consideration explains how with similar twisting forces from your hand produce different forces on the apex. With thicker blade, secondary bevel is large lever and thus resulting force is smaller. However with thinner blade, secondary bevels forming apex make a much shorter lever, thus force on the apex is multiplied more and twisting motion of the blade in the cut leads to chipping. Edge between primary and secondary bevel would not usually be a stress concentration, but it is the pivot around which twisting forces occur.
I have a some sort of japanese titanium kitchen knife with very rounded, sharp tipped edge that is a thin blade. I find it really nice knife, but really difficult to sharpen successfully, it's basically cutting with the geometry since day one. Like to be able to follow the curve is so difficult and trying to finish by making the burr disappear is just never ending thing, feels like even when you manage to do that, it still won't cut paper like butter. I suppose the edge material is also more difficult to sharpen. So in a sense, a point for your average cheap kitchen knife just for the sake of shape and material making it easy to repeatedly make sharp again. Then I remembered your tips about stropping and realized I have a strop belt for shaving razor blade and alas, few passes and the performance increased by factors. Thanks! I'm thinking looking at FEM simulation or just structural integrity calculations/graphs for shear forces and tensions, you would find the breaks often if not always occur at those transitional planes (unless it's like pitting or some other form of surface wear). They are usually the places where the supporting forces and stressing forces peak and/or change sides causing the high shear forces. The strength/resistance against tensions is also defined per the perpendicular section area. This from the top of memory so details and some terms might not be accurate, and I don't think this is very coherent, but I believe this to explain some of it.
So do you think an optimal thickness behind the edge would be something like 18 thousands behind the edge for strength and slicing ability? I was thinking about thining out one of my Cruwear pm2's and wanted to get your opinion.
I have this 3.5 euros chinese "knife" (a chinese cleaver) which is literalliy a stamped steel handle welded on piece of sheet metal with a very narrow andgle towards the edge. I keep it well sharpened but it works much better than the much more expensive chef knives I have if you want to chop up stuff.
maybe I missed it but how do you define "behind the edge"? How far from the edge are you trying to measure? looks like you're poking a pair of calipers on the bevel and eyeballing it. unless you're going for the widest part of the bevel, I just can't picture getting an accurate measurement (and if you are, I cannot imagine a paper thin primary grind behind the bevel)
The measurement was taken right behind the secondary bevel. Right on the corner or the secondary and primary. And yes the primary bevel really is that thin.
Because scandi knives cut horribly through something like an onion unless the blade is incredibly thin in general like a filet knife, which would be floppy.
Probably the best value for a good sharpening stone right now⬇
amzn.to/3fUilj5
Or my website www.outdoors55.com/shop where I go over knife sharpening stones / equipment, knives, and knife making equipment I have personally used and reviewed.
As an Amazon associate I earn from qualifying purchases.
Hey there is a scammer in the comment section! Be aware!
@@lionknives3 I was wondering what that was all about.
@@flyfishbrad that happened many times on many channels.
Yes, Unfortunately the only thing i can do is block them but then 3 more appear. Sorry I dont do giveaways. You can pretty much count on the fact that no TH-camr is doing giveaways in the comments. Thats not how anyone would contact you for a giveaway. I would think 99.99% of people would know this by now.
What would happen if the corners in the transition from the .008 to the edge were rounded instead of being such sharp transitions?
I would like to see a real time - no cuts sharpening video. Your videos always get a like from me. Thanks for breaking this down into crayons for me & anyone else that watches.
Me too
👍
I don't really see the point of a real time no cuts sharpening video unless you enjoy the asmr aspect. there isn't a whole lot to see generally.
"no cuts"
"sharpening"
heh
I can see why the explaining of that felt odd but I think you hit the nail right on the head. The big takeaway is that there is a geometry for each use case. Cutting soft veggies - a thin thin edge has a load of benefits. On the other extreme is the battoning you mentioned and that definitely requires a heavy edge if you want the blade to survive. We need more of these education videos in the community, thanks.
What we need is more people who aren't afraid to say batoning is a stupid use for a knife, for the same reason you don't fillet fish with an axe.
@@redrustyhill2I get what you’re saying which is why I’ve always used a hatchet. My guess is that when people baton with a knife is because they don’t want to carry around a hatchet when out bushcrafting 🤷♂️
@taylorbrandon86 any real "bushcrafter" will have the proper tools for the job. This whole "survival" nonsense stems from these stupid reality "survival" shows, thinking they will build a shelter and traps with nothing but a belt knife.
True of s110v. Heat treat and steel selection could also help limit chipping in that situation. But still holds true what you've demonstrated, just takes more force. Thats why when we buy thin knives we should know how to use them. Thats why some makers talk to customers to make sure they understand this and to not cut any hard materials with the super thin geometry.
I have a playl-ist section on my page for geometry for more on the subject, I think I'll add this one to the mix. Check out the others too.
This may be the first time in a couple of years of delving into this stuff that I'm hearing a person say there was a potential price to be paid in thinning a knife. Yes, it's often said you don't want to have an edge angle so acute the metal can't support it. But thinning behind the edge? No warnings ever that I can recall. So this is next-level understanding, as usual. Thanks and keep it coming.
I have many different knives and they all have a specific purpose. They're all sharp and do whatever they were created for very well. Not to say that I've never chopped onions with my pocket knife because I have. My dad was a butcher and he had knives for everything and they were good knives. He died when I was 18 years old in 1971 but he told my mother to be sure that I got them. I cherish them and still remember how he showed me to clean them, store them and to keep an edge on them. I think some sharpening techniques I've learned from you and others are better techniques (Sorry Pop!) and the stones we have available today are certainly better than was available to him! But he told me something one time that I've never forgotten. He said: "Son, it's just as easy to carry a sharp knife as it is a dull knife". My pocket knife back when I was a kid was normally dull, very dull. But when you're a kid you're busy playing and I used that poor knife for every kind of tool when I was working on my bike or something else. He always gave me a hard time about not keeping it sharp. I keep it sharp now and never use it for a pry bar! When I think back on my life back then I feel kind of cheated that I didn't get to spend more years with him. After all of these years I still miss the hell out of him.
Anyway, enough sadness. I'm happy to see that you're back and posting on a kind of regular basis again. You're my favorite knife channel and hopefully with more room now you may even build another knife from time to time. Thanks for the video!
What a beautiful comment
Great video. Shows well pros and cons of a thin geometry.
AEB-L probably would not chip with the same thin geometry. Clean carbides, high hardness potential and high toughness. That's why I think AEB-L is such a good steel. Cheap to make and outperforms several super steels in many tasks.
To cut highly abrasive materials powder metallurgy still shines.
Aebl is slept on but it's so good for so many reasons
@@NSW15355 True.
If you want to optimize for slicing AEB-L has higher toughness on 64 HRC than 1.4116 on 57HRC.
If you want to optimize for toughness it gets four times tougher than 1095 on same hardness while also being stainless.
It's a freaking beast but unfortunately it doesn't get top grade heat treatment from pretty much any of the large companies.
@@thiago.assumpcao aebl has history too. I think it was deployed in the 1950s as a razor blade steel for shaving. I was always drawn to it's ability to remain stable with a thin cross section and fine grain. And being stainless is nice
In solid mechanics, a stress concentration (also called a stress raiser or a stress riser) is a location in an object where the stress is significantly greater than the surrounding region. Stress concentrations occur when there are irregularities in the geometry or material of a structural component that cause an interruption to the flow of stress. Wondering if you can round the part where the edge and the blade meet.
That's how I sharpen my chisels. Can't say with any scientific certainty but it does feel resiliant and stronger edit: and very seldom get chips in the blades.
This is the correct explanation as far as I'm aware as material scientist. At the same time the procedure of thinning the blade without proper heat treatments in between and at the end could have weakened the steel a lot (initiation and lengthening of cracks). Grinding the steel puts a lot of plastic deformation in the steel which needs to be removed regularly.
As someone who has basically no real experience or knowledge regarding knives or steels in general I suspect the blade would just chip at a more random spot along the curve.
My thoughts exactly
In my experience, stress concentrators mostly occur if the sharp corner is to the inside of the part, like a scratch(or a bigger similar geometry). Rounding the part where the blade meeds the edge might still help with the resistance by making the whole area more elastic.
The fundamental factor at play here is anisotropy. In the thicker blade more of the material immediately adjoining the break site is being supported along stronger axes.
You could go more into depth in terms of crystal structure/boundaries, but it all boils down to the same thing.
Love this video. Kind of a surprise attack, I thought you were gonna recommend we all grind to .008" behind the blade. And then you gave us the, "But wait, there's more." The ideal behind-the-blade thickness is probably (entirely) task oriented. In kitchen knives, for example, guess I'd love to have a whole block of chef's knives with slots marked, .008 (maybe for sushi fish), .016 (boneless steaks), .024 (soft vegetables), .030 (carrots and potatoes). Chuckling...thanks for passing along your experiences and research.
Excellent job explaining and showing why the chipping occurred. Great job! Been a sub for a few years and your video style as well as all the info you give is why I still watch. Education and information 👊🏽
I'm a mechanical engineer. My intuition is that your explanation is correct. You also briefly mentioned stress risers, and I think that is also relevant. It would be interesting to model a few knife edges and do finite element analysis to try to backup or disprove these ideas.
He also isn't considering Hertz contact stresses. The max shear stress plain is larger with the thicker blade and thus the shear stresses are less.
I'd etch it and micrograph it at the chip site and along the now stressed edge. I'm thinking it's grain and grain support failure in this specific failure mode.
Hollow grinding has been the industry standard for most knives for a long time, except for the Nordic countries where we use "Scandi grind" (although I think it's a bad term since Finland is not in Scandinavia, and is a very important country in Nordic knife culture). Scandi grind leaves more material behind the apex, while keeping the blade thin.
I had a benchmade that I ground out to a long secondary bevel and a thinner primary. The steel was S30V. The edge literally flaked and crumbed from skinning some electrical wire for a splice. Prior to the sharpening, I could nearly baton the blade through a bundle of wire with no discernible damage. Great video and explanation. I’m wondering if steel type matters here as well? I’ve heard S30V is prone to flaking.
8:19 I could be wrong but i don't think it's really the size behind the sharp edge that make the apex strong. What i think happen is as you put your blade deeper into any item, the sides help cut by spreading out whatever items you are cutting through, therefor reducing the load on the tips. (It could also be a mix of what i just said and what you said at :19.. :) )
When you use an axe to chop in half a log, the sharp edge beging the work, and the thicker sides continue the harder work. You would not be able to split a log in half with only the thickness of the sharp axe edge using the same amount of force and head weight.
Definitely a great video.
That's one thing that definitely matters a lot. Also like you said at the end, the task the knife is intended for, the hardness, the carbide volume (also carbide size to some degree), all matter a lot too. Especially when getting down to those thinness'.
Something that's able to maintain good toughness, high hardness, while having just the right volume of small carbides, tends to do very well with thin grinds. Though even low toughness, higher hardness, and higher carbide steels can Excell, if the tasks theyre used for, don't involve impacts, or torquing the edge.
That actually made sense! You baffled me with the same angle but then it all came together with the thickness behind the Apex. Cheers mate!
So something you should try doing is create a micro bevel with the 8 thou blade and compare it to something similar with a 30 thou blade and no microbevel. that would be interesting to see. keep it up!
I have 2 SAK knives with 2 different blade thicknesses. One is an officer model with a master blade for an 84 mm knife and the second is a 93 mm blade that is thicker. I like to get them to shave arm hair without pulling. The smaller knife achieves this much easier and quicker than the larger knife meant for heavier work. This video confirms why some knives have always been harder to achieve this level of sharpness as well. I have had several knives in the past from major manufactures, where certain knives sharpened easier and better than others of the same make or model. I always thought it was my inability but now I think it had to do with geometry too. Thank you for this great informative video! Jeff
This video came at the perfect moment: Just had chipping issue with one of my whittling knives which I thinned down. Thought it would cut wood like butter, but ended up chipping and making ugly scratches in the wood. Thanks for explaining. I’m working on restoring it now. Gently, because the blade of a detail whittling knife is not very high. Keep up the good work 😀👍🏻
This is one of the most interesting videos I have seen in awhile, and I really learned a lot; thank you good sir
For metal stability, it helps to draw in the force lines. This tells us, that rounding the edges between the triangle and the parallel surfaces can help to reduce the stress in the edges
edit your OP with a picture like that shows?...wait no i think YT deletes links now. fuck YT
I noticed the strokes weren't very smooth. I figured it was dull, but when you rubbed your hand on the blade, I was genuinely confused. I didn't think it was THAT dull.
Well done and very informative. I now have two related questions: 1) is there an optimal blade thickness for a given secondary bevel angle? and 2) is your Manix blade now ruined? How would you fix that?
No, it would depend on the end use of the knife. The manix ist ruined at all. Its thinner but I brought the bevel back and that added a couple thousands. Im working on a video showing me fix it.👍
@@OUTDOORS55 Thank you, Sir! Your videos are interesting and helpful.
Your demonstration with the cardboard cutouts was ingenious in its simplicity!!!
...who didn't understand that should stick to spoons rather than knives.
Nice Video very informative especially the demo about the knife geometry /angle when you showed the wood triangle comparison very impressive your'e the only person who showed something like that ..Thank you for sharing .👏👍🏼
the explaination got to me at the end of when you were explaining it, as a foreigner i think your explaination was as clear as water
I always learn and enjoy your videos. Thanks for your time !
Good to see you back doing what no one else seems to be able to cover
Would you try a convex edge on your .008“ Manix? I think it would eliminate the chipping because it’s more „natural“ ( less hard edges ) edge.
Nice video! Take care!
Actually, the explanation was very clear and easy to understand, thanks you so much 👌🏻
I think the explanation was perfect and in fact, i’ve read and heard that is the main reasons why convex edges are so strong.
To reduce the stress riser you might roll the blade side into the apex angle instead of a sharp division.
Excellent, as usual. I doubt that many people have the power tools to reshape the primary bevel. I think that I will concentrate on my basic technique.
I had no idea about this so it was very valuable info. That you for the good quality video!! And, thank you for your good sense of hummer!!!
Wow!! The amount of effort and knowledge that you put into your videos is impressive!!
Your explanations are very good. As always. Anyone with common sense must understand these!
Love your humor!
Greetings from Germany💚🤘
perhaps that is why so many luv a convex grind, a radius removes the weak point, and has some material behind it. that would make a great vid.
Very nice simplification in my mind. It is good enough to be useful. And I think it holds up in predictions well enough compared to going much further -- like thinking about why the "all this supporting material" is supporting in the first place.
Very educative and enlightening! You're very good!
10:20 the force is actually along the entirety of the side of the primary bevel, except in cases where you are purposefully pushing the blade in sideways. It’s just that the pressure is too large for even that area. If it was only on that point, then it would deform first (flattening out) becoming a new secondary bevel which would then break off. While the model is somewhat rudimentary and can’t completely describe the nuances of metallic deformation, it’s pretty close if you only consider the sides of the triangle instead of that point.
I is ve learned a lot from you my friend. I’ve ruined so many moras and my favorite knife the Ontario 1 folder. This helped me out a lot on sharpening
@UC8QKxrtolxCCaTrHv5VPGQg Thank you O55
Keep going budro! You are making people rethink "truths" about blades and sharpening
It has to do with hardness and flex. Your blade is a material that has a higher hardness value but you thinned the blade to the point where there's not enough supporting material to resist the edge from flexing beyond the fail point and the hardness alone isn't enough to prevent the edge from flexing during normal operation.
Thanks for sharing! I learned a lot! Since the weak point of the edge is the pointed shoulder of the apex (possibly due to the abrupt change in angle on a microscopic scale between the primary bevel and secondary bevel), what if you were to round or convex the shoulder? Could that increase the strength of the edge? Just a thought.
That's why Mike Stewart of Bark River Knives mostly does convex grinds. He says it supports the edge better.
That must be why my s110v Native that is now almost a scandi grind seems to hold up so well. The consistent great videos is astounding 👏🙏
great vid!
you may even say steel typeband heat treat are serve to allow a specific geometry. Usage dictates geometry and thus dictates steel typeand heat treat
What would be considered the closest to being the perfect sharpness for a knife and how would that then be achieved???
Really enjoyed the video, yet I believe you missed something: steels like s110v have an high volume of carbides, those can be either alone but are usually distributed in relatively small clusters, sized if I remember correctly in the range of 10 to 20 microns, those groups of carbides in very thin edge configurations may not be properly supported by the steel matrix, causing small edge blowouts.
Finer grained, less carbide heavy steels may perform better: my spyderco chaparral right now is 7-10 tho bte, yet shows no significant chipping, even in rough cutting like chest-lever cuts on branches and whatnot
Something like for example your 1084 should have nicer properties for that kind of edge imo
Keep up with content, your channel is great!
Im not sure thats the case here due to where the chips propagated, which was right at the corner of the secondary bevel. Id lean more towards carbide if it was more towards the apex. Very good thought 👍
Realy enjoying your video's.
I have learned to sharpening my knives by watching your video's 👍🏼. Thank you 👍🏼
You should try sharpening at a more acute angle since the blade is now thinner, it sounds counterintuitive but it absolutely *could* be the reason for the chippiness
Fantastic video btw!
Nice. Love the contrast of that project compared to the axe grinding video. Kind of both ends of the spectrum.
this remmember me of the katana, perfect o cut joints, but so thin, it can break with easy in no trained hands!
I have been wondering for the last week: Why can't I get a cheap chef knife with super steel as a backup survival knife? Well, 11:19 was what I needed. ;) I should have known this since I grew up in the house of a knifemaker, but It never made sense until this video. Thank you for sharing your knowledge.
Make a sharpening asmr video then do cut test the same way as the blade dulls and the pitch decreases. Love your in depth videos. 😍
Please make real time sharpening video for that Manix 2 because I have the same and it is new so I dont have any experience with sharpening s110V! Thanks in advance
I'm convinced (science, it's like magic,but it's REAL). Finally, someone who knows what makes a good blade. I'm gonna be a loyal subscriber, keep it up.
Is that the CBN spyderco stone? If so how do you like it?
I never ever seen anyone go in depth about knives like this, w find.
Brilliant mate, knew about it but could never figure out exactly why. Thanks 👍
Would this change the strength by flattening the angle of the final bevel?
So in your opinion, if you could choose, what steel or steels would be tough enough to not chip at 8 th behind the edge, and in hindsight would you now go for 10 thou bte for more compromise of slicing and toughness??
I have had this issue before with a victorinox boning knife. I had to increase my sharpening angle before it stopped chipping. I think i set the angle to about 22° till i had a edge that seemed usable. Where my thicker santoku knife will handle 17° no problem.
So what do you do now? Widen the apex?
Makes perfect sense & your videos & editing I envy.
Is there a chance you've applied to much head during thinning and it caused unwanted tempering / heat treatment issue?
Great demo btw
Sure that could be a technicality but when a blade is tempered it is heated to red hot temperatures. If the edge was that hot then the sandpaper would've caught fire and the rest of the blade would've been too hot to hold. Tempering should not be a concern when sharpening.
@@Demogorgon000nonsense. Heat treatment or temper, can be lost at well below red hot. Its very easy to quickly destroy a tempered blade with power tools.
just a thought
copper wire is soft and sticky . you may have put the apex in a vise , with some off center pressure ..cut strait down to a surface maybe no problem
please your thoughts
Geometry definitely cuts. I bought a Robert Herder paring knife and it was 2-3 thou tops(it's pretty much a zero ffg grind with a microbevel put on) and 44 thou blade stock and even it was dull from factory it cut cardboard almost as well as my razor sharp pm2 regrind to 0.005. After I actually sharpened it is the best light to medium duty cutter I've experienced. Not every knife needs to be 5-10 thou bte but for certain ones it is really nice.
I have the exact same pair of calipers. Mine were in the case on my night stand next to me I pulled em out to make sure lol. I have another pair from Clockwise Tools that I prefer. Gives regular metric and imperial but also fractions so if somethings 3/8 I don't need to look at a chart. Also bigger screen which I friggen love. $25 on Amazon
One of the best knife sharpeners ive ever come across had a surprising source. It was the arc tube out of a bad sodium vapor lamp. It would put a super sharp edge on almost anything 🤓😁❤
I would be interested to see whether the knife could have survived those tasks if it did not have a secondary bevel. I have a few knives that I have sharpened to that thinness, but I did not intentionally add a bevel. They may have a microbevel since hand sharpening isn't very precise. I haven't had any chipping or rolling yet but the steels are not comparable. Mine are 4116, 12C27N and 14C28N. I'm not about to risk my Maxamet Manix like that.
Sorry if i didn't see this in the comments, does anyone know if blade/edge stiffness plays into this? Does the thinner support material tend to flex and let the edge go wobbly in a way that could allow chips to pop off?
i love the beard
and also welcome back and thanks for the video i learned alot
i hope you talk more about carbides i read so many articles on knife steel nerds
I know this is an old video, but can you do testing to see what thickness is the best for cutting while reducing the chance of chipping? Would the thickness of a utility blade be the best, or should it be thicker than that?
I'm not sure if it's possible with that thin a primary grind, but would an "apple seed" grind be a little more resistant to chipping?
Would a thinner blade with a more shallow secondary bevel change any thing in a scenario like this?
That was a good explaination!
Would thinner geo be better suited to a chisle grind?
What about a video where you improve the geometry of kitchen knives? What are some tools that you can use at homes? Maybe a deep dive into products on the market which have better geometry than the rest?
So, when my mom said "You ain't the sharpest knife in the drawer,"
she was actually giving me a compliment?
I suspect it has more to do with the change in angle at the bottom of the apex causing a stress concentration at that point, making it the point most vulnerable to chipping... which is why it tends to break there and not above or below. It's just that a full thickness blade has enough material at this vulnerable spot to prevent this failure mode under reasonable/normal use.
And you didn't loose the temperament of the steel by heating up the steel from grinding it down ? Or made it chippy by getting it hot. Then cooling it down rapidly ?
Since I am a stonemason, the image at 14:00 elicits a different impression. It reminds me of a stone edge when struct laterally by my hammer. Perhaps the little bumps of the sharpening media contacting the material at speed at that specific part of the blade produce unrecognized impacts. In the thicker blade, that same spot experiences zero impacts.
Am i correct to assume that if the primary bevel is too thin like in some japanese knives that i need a large apex angle?
Great video, welcome back. Given that video can you give some suggestions for great geometry blades? I love my 940 but not the best slicer. Just a couple of your favorite folders. Any others than Manix?
What about convex grind in addition to thinning?
Enjoyed the video, and it made me think of the benefits of convex grinds as well
What if you made the blade slightly rounded so the support is still there but it's not consistent triangle more like a sharpened parabola?
This reminds me so much of those scored "snap" utility blades, where you just break off the section that becomes dull.
Its a common occurence to experience chipping like this in my profession (mechanic, we use razors all the time) and razors chip right at the very apex often, but we also break them regularly because they are flimsy little pieces of metal (so is a bullet, but thats a different topic lol🤣).
Always look forward to and enjoy your videos. Thanks for the time you put into this. There isn't a ton of TH-cam videos focusing on geometry, toughness, and heat treating so that information is much appreciated.
I think you should consider how the chipping occurs. Presuming it's side load, leverage consideration explains how with similar twisting forces from your hand produce different forces on the apex. With thicker blade, secondary bevel is large lever and thus resulting force is smaller. However with thinner blade, secondary bevels forming apex make a much shorter lever, thus force on the apex is multiplied more and twisting motion of the blade in the cut leads to chipping. Edge between primary and secondary bevel would not usually be a stress concentration, but it is the pivot around which twisting forces occur.
Not ak knife person and in no means smart but would making the edge less shallow help or would it make it even easier to chip asking for a friend here
What's the best thickness for a sharp CONVEX edge?
I have a some sort of japanese titanium kitchen knife with very rounded, sharp tipped edge that is a thin blade. I find it really nice knife, but really difficult to sharpen successfully, it's basically cutting with the geometry since day one. Like to be able to follow the curve is so difficult and trying to finish by making the burr disappear is just never ending thing, feels like even when you manage to do that, it still won't cut paper like butter. I suppose the edge material is also more difficult to sharpen. So in a sense, a point for your average cheap kitchen knife just for the sake of shape and material making it easy to repeatedly make sharp again.
Then I remembered your tips about stropping and realized I have a strop belt for shaving razor blade and alas, few passes and the performance increased by factors. Thanks!
I'm thinking looking at FEM simulation or just structural integrity calculations/graphs for shear forces and tensions, you would find the breaks often if not always occur at those transitional planes (unless it's like pitting or some other form of surface wear). They are usually the places where the supporting forces and stressing forces peak and/or change sides causing the high shear forces. The strength/resistance against tensions is also defined per the perpendicular section area. This from the top of memory so details and some terms might not be accurate, and I don't think this is very coherent, but I believe this to explain some of it.
So do you think an optimal thickness behind the edge would be something like 18 thousands behind the edge for strength and slicing ability? I was thinking about thining out one of my Cruwear pm2's and wanted to get your opinion.
How thick can a knife get. Could you just take the angle of the apex and make the axes longer .. so that there is no secondary bevel?
Is this knife then broken beyond repair from here on out 😢 or is there still a way to get it not “chippy”? Excellent video once again.
I have this 3.5 euros chinese "knife" (a chinese cleaver) which is literalliy a stamped steel handle welded on piece of sheet metal with a very narrow andgle towards the edge. I keep it well sharpened but it works much better than the much more expensive chef knives I have if you want to chop up stuff.
maybe I missed it but how do you define "behind the edge"? How far from the edge are you trying to measure? looks like you're poking a pair of calipers on the bevel and eyeballing it. unless you're going for the widest part of the bevel, I just can't picture getting an accurate measurement (and if you are, I cannot imagine a paper thin primary grind behind the bevel)
The measurement was taken right behind the secondary bevel. Right on the corner or the secondary and primary. And yes the primary bevel really is that thin.
Why not use a scandi grind or sabre grind? Why do you put a secondary bevel on your knives? Do you have a video explaining this?
Because scandi knives cut horribly through something like an onion unless the blade is incredibly thin in general like a filet knife, which would be floppy.
Perfectly explained!