Mirror vs Toothy Edges
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- Опубликовано: 14 янв 2024
- This was an attempt to test the theory that mirrored, or highly polished edges, aren't desirable for food prep tasks like slicing tomatoes, because they skate across the skin. I compared a 600 grit edge to a 4000 grit edge to see they compared. The results were ... unsatisfying?
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This channel would be on daytime programming. Seemingly boring but infinitely educational. haha keepin' it alive!
I am the CSPAN of RUclips. lol
An educational and enjoyable watch. Thanks for posting.
The big question! Nice video!
I'm an professional chef and knife sharpener and I always go with toothy edges for my work knives, only my miyabi with 67 HRC gets a fine finish because supersteel like that will get its micro serration over time
In the kitchen, with very freshly sharpened edges at maximum sharpness, I've found that the most refined edge / the one that is actually "sharpest" will always cut the best.
Where the difference really starts to show is how cutting performance changes as the edges start to degrade. The "drop-off" in performance for a high-polish edge is much steeper than a toothier edge. In a professional setting where the edges are going to see thousands of cuts in just 1 shift, or in a home non-knifenerd home where the edges might go MONTHS between sharpenings, the polished edge is going to start to really struggle while the toothy edge will keep (ungalmourously) sawing along.
Lot's of factors (harness, toughness, abrasion resistance, grain structure/ carbide size) are all going to play a factor in how well a particular blade can take and hold onto a polished edge. Many softer / more affordable knives will not even make it through a full shift without serious degradation of the performance of a polished edge.
Totally agree. I would only recommend a high-grit finish for someone who knows how to maintain the edge, and is committed to doing so. That's a pretty small cohort.
@BladeLabMiami I'd also add that beyond a certain level of sharpness, things like edge geometry and blade thickness (especially behind the edge) are going to make way more difference in how it "feels" to use a knife and the easy of operation.
Mirror edges are definitely the better edges, it's just that almost everyone applies them badly and screws up the geometry in the process. I apply a mirror polish at a precisely controlled angle on precision, adhesive-backed, diamond lapping films attached to hard anodized aluminum. I use this method down to about .1 micron and then deburr at 1 micron with monocrystalline diamond emulsion on a flat synthetic medium. This routinely produces stable edges that measure well below 100 on the BESS scale. They don't "skate across" anything that isn't harder than the blade. That being said, the effort to properly produce a mirror-polished edge isn't always worth the effort. The amount of use experienced by a kitchen knife usually doesn't warrant keeping it polished to a high degree. It's not that a "toothy" edge works better, it's just that it works more than well enough and the work to improve it reaches a point of diminishing returns. An extra-fine ceramic rod for maintenance and an occasional rebeveling at a lower angle on stones are usually all that's needed for a knife that experiences nothing but daily food prep. The only time I go with something more precise in the kitchen is when I want to do extremely precise work. Examples would be sashimi, carpaccio, and other, usually highly decorative preparations.
Totally agree that a freshly sharpened mirror edge cuts like a laser beam. Where it becomes an issue is when you lose that initial bite. Then, I think a medium-grit edge usually cuts better because you have that micro-serration, whereas a mirror edge just becomes smooth.
The methodology used to do the polishing makes a lot of difference. The problem gets much worse when people polish using methods that round the apex, even at a microscopic level. This leaves a poorer geometry to take up the slack as the edge begins to dull. Proper sharpness is genuinely just a matter of unit pressure. @@BladeLabMiami
i liked the test.
this(kitchen knives) was the reason why i started playing with leaving a lower grit finis on edges.
I also used victorinox knives. I left a 60 micron edge on and stropped it on leather loaded with white brkt compound.
What I found was what polished (not necessarily polished as in mirror, just a higher grit and stropped a bit more)edges were more resistant to damage( i used lower edge angles 8-10 dps) and in time felt sharper and cut better. The toothy edges while grabbing the skin of vegetable and having a wonderful feedback, did not last as long. I tried this in real life use over months...and I still want to find a way to have a toothy edge that lasts longer and is more resistant to damage than a more polished edge.
however....i think the steel is not the right choice. a steel with hard carbides might lead to a different result. but then you do have the choice of deciding do i use my knives for push or slice cuts...
what i found interesting was that you got them to the same level of sharpness measured on your bess...at that point, wasn't the toothy edge just as "polished" as the other one?
Thanks for the video!
Thanks for watching, and for the thoughtful comments! I think that, with softer steels, a toothy edge does lead to faster wear. It's probably the micro-serrations flattening out. For my personal knives, I finish at 600 grit, but I frequently strop them using 1 micron diamond and AlOx compounds, so what starts out as toothy becomes refined rather quickly. If I'm sharpening for someone else, I'll finish at 1000 grit because I know there's not going to be a lot of stropping going on.
As far as the BESS tester goes, I think higher grit edges do have a slight advantage, but you can still get very low scores with lower grit finishes. I think that's because -- even though the filament is thin (0.13 mm), it's not really thin in relation to the size of the micro-serrations left by a medium grit stone or plate. It's measuring the diameter of the apex in that .13 mm section, and I think that's wide enough to bridge the serrations. .13 mm = 130 microns, whereas 600 grit = 30 microns. That's my theory, anyway!
@@BladeLabMiami i like your tests and how you explain them. I have never sharpened on a tormek so i do not know how the edges come off. it is nice to see.
for me...it is most interesting to find a balance between a finish which will help out in edge retention and cutting aggression. with S110V I found that a high polish(even if a lot of people advise against it because you lose cutting aggression) works best for all materials. And so far, with normal use, except for that tiny chip on the tip(and that was user error), i have not noticed edge failure due to fatigue from excessive stropping. your test with the M4 Tenacious was great in that sense because your camera did not get the first run so you stropped it back. i think that was cool as they didn't start the test with "fresh edges"
Im more of a pocket knife guy but i stumbled across this video.
Something ive noticed, is that softer steels and steels with particularly large carbides perform better with "toothy" edges.
harder carbon steels, and powder metallurgy steels perform better with polished edges.
A 3v blade ill only stick on a 120 grit stone, but s110v and zdp189 ill bring all the way to 10,000 and then go to diamond emulsions.
I think one of the reasons you see such a quick dropoff in sharpness with the polished edge, is due to the softness of the victorinox steel. Id be interested in seeing this same test done with a steel like Blue #2
I use a polished edge on my straight razors and high end Japanese blades. Both of those have extremely thin blade material behind the edge and they work extremely well with a polished, honed edge.
For "normal" cutting work I much prefer a "toothy" edge. Polished works but the difference for me is that when a polished edge becomes imperfect on these blades it loses a lot of its functionality faster (i.e. it isn't as durable of an edge). A toothy edge with some minor wear on it is pretty close to original performance.
The vertical cutting performance (without a slicing action) is strongly impacted by the effect of edge geometry rather than sharpness so it isn't much of a surprise that they are so similar (IMHO).
I have the exact opposite experience. Polished edges consistently last longer for me.
It's all about the steel you're using
Thanks for doing this test! I have found that a highly polished edge cuts better and lasts longer. Edge geometry is also important, and unless I’m missing something, your test compares a toothy convex edge (Ken Onion belt) to a highly polished concave edge (Tormek). Since convex edges generally cut better and last longer, your test may be slightly flawed…In other words, the polished edge might cut even better if it was a convex edge.
Both of the knives were sharpened on the Tormek and then stropped on the Ken Onion with leather belts, so the edge bevels had the same shape (very slightly concave). The difference was that the toothy knife was sharpened exclusively on a 600 grit wheel, while the polished knife was finished on a 4000 grit wheel.
In my experience, the 600 grit edge stays sharp longer than the polished edge, which has been born out in other testing by Knife Grinders Australia. Of course that's assuming that they were equally sharp to begin with.
Oh ok…that makes sense. Thanks again!
For sawing through things a toothy edge is the way for push cuts a polished. And a serrated edge for cheese. Trust me
Also serrated for bread, no question.
Yeah
What kind of cheese do you cut with a serrated knife?
@@monkpato mostly Gouda. It's super soft and squishy. With those cheap Victorinox right hand serrated edge you know
Interesting experiment but I could’ve done without the coughing and eating noises on my earphones.
Fair. 😅
Ah hahaha
I thought for sure we were going to get to see whether a polished or toothy blade cuts flesh better. 😯
I find the toothy edge more helpful on tougher things like that cheep yellow plastic rope. Or in the kitchen when you go to cut an onion, and it still has 5 layers of that dried brown skin on it. It seems like my polished edges will just slip across the surface, and a toothy edge bits in and cuts through. I don't know it's a tough call. The one place I will argue for a polished edge all day every day is on my straight razors. I know apples and oranges to what you're talking about.
Good video though thanks for sharing.
100%, you would not want a toothy edge on a straight razor!
no. if your polished edge can't initate a cut, then you should learn how to sharpen. also learn how to read and read a book. maybe try "knife engineering" by larrin thomas and learn something.
When it comes to brown onion skin, I usually make sure I've rubbed all of it off with my hands but the last, very adhesive layers. I've never seen a sharp knife, polished or otherwise, have a problem with that. You leave five layers of that stuff on though? I wouldn't be surprised to see Obi-Wan's lightsaber slip off. Razors DEFINITELY need a polished edge as does anything required to make a strict "push-cut".
This is a lot of overthinking I have for my taste but it was very well done and I watched the whole thing
I have the same results. Toothy and polished edges have more or less the same edge retention after 200 cuts and slice more or less the same. Polished edges skates on plastics, but need less pressure to make the cut.
It would be interested to check how many slices take each knive to reach the limit, maybe 600 or 700 BESS.
Also agreed. Very boring video, but super educational
Cool content.. 👍👍🔪
a lightly polished toothy edge for the win
It’s really an exercise in impossibly. As the apex is worn away by the wheel, the wheel is worn away by the abrasion. That causes the distance between the two surfaces to change and thus the angle must change. On top of that, there’s really no such thing as a mirrored surface. At some point we are at the molecular level and ultimately all material in the universe is jagged by the nature of atomic structure. The edge of the knife and the absolute edge of the tomato skin. This is why I say it’s an exercise in impossibly. What you are doing is getting near to something, but the ultimate goal is impossible to achieve. At that point we all are required to accept it as “good enough”.
where can we download that app ?
You can find all the info. on it here:
forum.tormek.com/index.php?topic=4373.0
thanks sir
@@BladeLabMiami
Ive said it before and I say it again, a "toothy" edge is a crutch for people with bad sharpening skills.
Американцы никогда не умели точить ножи, и никогда ее умели анализировать результаты. Я думал этот человек будет долго резать разные материалы. Но он немного порезал томат и почавкал. И сделал выводы.
Translation (partial): "Americans have never been able to sharpen knives."
Okay. 😂
knife bros believe lots of things. most of it nonsense. here's the actual difference. courser edges have slightly more edge retention in catra tests.. thats a fact. whereas if you use a correct abrasive that's finer than the smallest carbides in a given steel, aka polished, the edge becomes less likely to fracture/chip. so the choice is this. do you want a little bit more edge retention, or do you want a little bit more resistance to chipping? that's all there is to it. these are actual facts, which are based on something called empirical evidence. all this other stuff is just nonsense from folks who don't understand how knives work. keenness of an edge and sharpness, is it the same thing? whats called "cutting ability." what is "bite" that's cut initiation. what is keen aka "sharp" literally on physical level it's the radius of the apex. does that make sense? it doesnt make one lick of difference if it's "toothy" or "polished." the smaller the radius of the apex, aka more acute, the keener the edge. the better the cut initiation. cutting ability is different and based on the geometry of the knife itself. thinner edges cut better, crazy right? get it together knife bros. if your polished edge lacks bite, then guess what? you should learn how to sharpen. let me repeat what I said. cut initiation is associated with apex acuity, aka the smaller the radius of the apex the keener the edge the easier it initiates a cut, aka "bite" aka associated with push cutting. this is not the same thing as "sharp" or cutting ability.
I believe this is somewhat reductive. Cut initiation isn't simply a factor of the radius of the apex. If it was, e.g., a very sharp chef's knife would slice hard wood better than a saw blade. But we know that isn't the case. A raggedy serrated knife will initiate a cut in a tomato more easily than a very sharp but not shaving sharp mirror edge.
Great video for overall concept. Some feedback…. I was alarmed by your cutting toward your fingers to the point I nearly had to stop watching. Unsafe at best. I’d also refrain from eating while filming as the sounds were unpleasant.
Это ужасные тесты и ужасные выводы. Большинство тестов на канате полированная кромка лучше режет и режет дольше. Есть тысячи сравнений этих кромок. Toothy edge это просто хуже заточенная кромка, кому точить лень. Большинство комментариев тут пишут люди, которые видимо вообще не смотрели сравнения на RUclips
Actually, the most scientific tests that I know of were conducted by Larrin Thomas, a PhD metallurgist, who found that edges sharpened at a relatively coarse 600 grit almost universally cut longer than edges sharpened at higher grit ratings.
Smacking you lips and slurping tomatoes during a sharpening video is crass and unprofessional. Please do better