# about edge retetion testing



## inferno (Feb 21, 2020)

i have done some edge retention testing on cardboard and i can safely say it sucks ass.

so i had this r2 blade at hand. and i figured it would be totally dead at about 2 cardboard boxes. i have tried an r2 blade before and it was dead after 0,5+0,5 boxes, really dull. then i tried this out another time at work. i figured another r2 blade would do fine as trial run but it turned out i could cut cardboard until the cows come home and then some.

before i had cut up 2 cardboard boxes and after that 2 knives were dull. 1 r2 and 1 aus8. but now at work i went through 175m of cardboard (documented) and the r2 blade would still slice paper cleanly. maybe i had more abrasive cardboard last time?? i dont know. turns out cardboard can be very different. with or without clay for instance.
at my job i has gathered about twice as much cardboard as i thought i would need. 2 ply 8,5mm but it turns out this means jack ****. because i could cut this **** for ages. and basically nothing would happen.

so far i have gotten calluses on my thumb and then i have over worked my right arm from all cutting. and then the handle cracked on my knife. but it was probably unrelated though.

in the end it turns out for me at least that pretty much all steels from japan except maybe globals will keep a good edge for as long as you would ever want it. i still cut about 150 more meters of CB with the r2 blade. it would still cut print paper. ymmv i guess. it definitely did with me.

that being said i dont trust catra tests more than my dick.

whats a good edge retentiion test we can all perform?? it has to be reproducable.

ideas?

for me at least cardboard is out of the game because of the varibility.


----------



## vicv (Feb 21, 2020)

It is difficult especially for kitchen knives. They don't really dull from abrasive wear. We don't cut abrasive materials, like cardboard, with kitchen knives. 
Your issues with catra tests doesn't correlate with your cardboard testing. As you've noticed different cardboard is different. Catra card stock is the same so results are repeatable. 
That being said as I said before catra testing doesn't correlate to kitchen use. 
I just use my knife till the edge loses its bite and then I bring the edge back by whatever means are necessary


----------



## M1k3 (Feb 21, 2020)

inferno said:


> i have done some edge retention testing on cardboard and i can safely say it sucks ass.
> 
> so i had this r2 blade at hand. and i figured it would be totally dead at about 2 cardboard boxes. i have tried an r2 blade before and it was dead after 0,5+0,5 boxes, really dull. then i tried this out another time at work. i figured another r2 blade would do fine as trial run but it turned out i could cut cardboard until the cows come home and then some.
> 
> ...



Nice test. You probably thought I was crazy in the other thread.


----------



## panda (Feb 21, 2020)

pineapple skin


----------



## madelinez (Feb 21, 2020)

Let me go buy 500 pineapples....


----------



## Barmoley (Feb 21, 2020)

vicv said:


> It is difficult especially for kitchen knives. They don't really dull from abrasive wear. We don't cut abrasive materials, like cardboard, with kitchen knives.
> Your issues with catra tests doesn't correlate with your cardboard testing. As you've noticed different cardboard is different. Catra card stock is the same so results are repeatable.
> That being said as I said before catra testing doesn't correlate to kitchen use.
> I just use my knife till the edge loses its bite and then I bring the edge back by whatever means are necessary


You can’t test steel differences by testing knives, too many variables. This is why catra testing works, you can keep most variables same so that differences in steels or heat treats of same steels can be compared in a repeatable manner. It doesn’t have to be catra, but a good test would have to be something very similar. Have you tried different steels in similar kitchen knives? Was there a difference in how long they stay sharp? Why does catra like testing works in every other industry, but it doesn’t work for kitchen knives? Why do more wear resistant steels tend to stay sharp longer than less wear resistant steels in kitchen knives? Does anyone think that in general blue super stays sharp longer than white 2 in kitchen knives or is it same, less?


----------



## Nikabrik (Feb 22, 2020)

Well, I'm very curious what Larrin & Shawn's "Super Secret Project" turns out to be, because it involves some form of sharpened test blades. I'd be very pleased if they introduce or validate a test.

I believe for his own development, Shawn has been doing a rope test cut where he measures loss of sharpness after a set number of cuts, using a BESS tester. Not everyone has one, though.

The cardboard testing done by a few YouTubers does seem to be fairly consistent from test to test, even with different testers - they're using a particular cardboard, and testing always in a 1" section of the blade. Sharpening media has been standardized for each tester, which has its merits and demerits.

I'm really interested in the idea of a DIY-able, quantifiable edge stability test. Roman Landes had an interesting test, but it's not really hobbyist-accessable. I think a simple fixture and a drop-weight might do the trick, as long as we had a way to measure the damage - although that could be rather challenging without specialized equipment.


----------



## Barmoley (Feb 22, 2020)

Nikabrik said:


> Well, I'm very curious what Larrin & Shawn's "Super Secret Project" turns out to be, because it involves some form of sharpened test blades. I'd be very pleased if they introduce or validate a test.
> 
> I believe for his own development, Shawn has been doing a rope test cut where he measures loss of sharpness after a set number of cuts, using a BESS tester. Not everyone has one, though.
> 
> ...


I am looking forward to that too. The problem is that no matter what test you design, you will get the same people complaining that it is not valid because it doesn't mirror their use exactly. It is always easy to complain and criticize while not doing anything yourself. It also seems that some people just can't make a mental jump from testing to real life. As if science doesn't work in every single industry in our world.


----------



## vicv (Feb 22, 2020)

Barmoley said:


> You can’t test steel differences by testing knives, too many variables. This is why catra testing works, you can keep most variables same so that differences in steels or heat treats of same steels can be compared in a repeatable manner. It doesn’t have to be catra, but a good test would have to be something very similar. Have you tried different steels in similar kitchen knives? Was there a difference in how long they stay sharp? Why does catra like testing works in every other industry, but it doesn’t work for kitchen knives? Why do more wear resistant steels tend to stay sharp longer than less wear resistant steels in kitchen knives? Does anyone think that in general blue super stays sharp longer than white 2 in kitchen knives or is it same, less?



Catra testing works to give an idea about performance in other industries because almost all industrial cutting involves abrasive materials. We don't have those in the kitchen. Sure your wood cutting board is mildly abrasive but you shouldn't be sawing at it. 
Generally high wear resistance steels are high alloy steel and need a proper heat treat. The carbon steel Japanese smiths use don't and most of them guess as to their austentizing temps and such so of course it's not going to perform at its best. Whereas sg2 and the like must be done with a digitally controlled furnace for a specific amount of time. It will get an excellent heat treat and perform much better


----------



## panda (Feb 22, 2020)

vicv said:


> Catra testing works to give an idea about performance in other industries because almost all industrial cutting involves abrasive materials. We don't have those in the kitchen. Sure your wood cutting board is mildly abrasive but you shouldn't be sawing at it.
> Generally high wear resistance steels are high alloy steel and need a proper heat treat. The carbon steel Japanese smiths use don't and most of them guess as to their austentizing temps and such so of course it's not going to perform at its best. Whereas sg2 and the like must be done with a digitally controlled furnace for a specific amount of time. It will get an excellent heat treat and perform much better


sg2 is trash


----------



## lemeneid (Feb 22, 2020)

Burrfection rope test is the only absolute benchmark for edge retention!


----------



## vicv (Feb 22, 2020)

I've never had an sg2 knife but I would have to say many people would disagree with you on that. Sg2/r2 has a reputation for being good. Ok let's say aeb-l then. That's one everyone can agree is a good steel.


----------



## Benuser (Feb 22, 2020)

vicv said:


> I've never had an sg2 knife but I would have to say many people would disagree with you on that. Sg2/r2 has a reputation for being good. Ok let's say aeb-l then. That's one everyone can agree is a good steel.


... all depending on the heat treatment it got. And even then, AEB-L isn't exactly well-known for its spectacular edge retention.


----------



## Benuser (Feb 22, 2020)

Just a few factors for edge retention come to mind: produce, if it is sandy; board contact: nature of the board; kind of contact, depending on the used technique (rocking, push-cutting, slicing); blade geometry: with less resistance less power is required, so the board contact will be softer; edge geometry: a thin edge with a robust microbevel will prevail; sharpening: a highly polished edge with large carbides may undermine edge stability.


----------



## Barmoley (Feb 22, 2020)

Benuser said:


> Just a few factors for edge retention come to mind: produce, if it is sandy; board contact: nature of the board; kind of contact, depending on the used technique (rocking, push-cutting, slicing); blade geometry: with less resistance less power is required, so the board contact will be softer; edge geometry: a thin edge with a robust microbevel will prevail; sharpening: a highly polished edge with large carbides may undermine edge stability.



You are absolutely right and all these reasons are why testing knives is so difficult, just too many variables. Spyderco probably came the closest with their mule program. Even then people could claim and did that because different steels were hardened to different hardness, this was the reason for differences in performance and some of it was that. At least the grinds and general shape of mules were the same and Spyderco is pretty good at heat treating.

Even if we took simple carbon steels, there is a general understanding that blue steels hold an edge longer than white steels in similar knives and that blue super is the king of slicing edge holding and holds the sharp edge longer than white 2. Since every thread needs to have TF discussion in it, take TF as an example, it is generally agreed that Denka edge lasts longer than Mabaroshi edge. One could claim that it has to do with hardness white 1 @65-66 vs Blue Super @66-67, but the edge seems to last a lot longer. It is reasonable to think that at least some of it comes from super being more wear resistant than white 1.

Larrin showed that CATRA results have a very high correlation to rope cutting test results as well as cardboard cutting test results, so it is reasonable to assume that it also has high correlation to food cutting test results too. Food is not very abrasive, but it is abrasive to some degree, take tomato skins for example. We are also dealing with very thin edges. Another example is yanagis, they dull and the white ones dull quicker than blue, these have practically no board contact at all and mostly cut very soft stuff. I think it is ignorant to think that wear resistance has no effect on slicing edge longevity. Or that CATRA is irrelevant because it doesn't test cutting tomatoes or potatoes or any other produce you like.


----------



## panda (Feb 22, 2020)

vicv said:


> I've never had an sg2 knife but I would have to say many people would disagree with you on that. Sg2/r2 has a reputation for being good. Ok let's say aeb-l then. That's one everyone can agree is a good steel.


I hate aeb-l too


----------



## Michi (Feb 22, 2020)

panda said:


> sg2 is trash


I’d be interested in hearing why you think so, despite a large number of reputable makers seeming to think that it is a good steel.


----------



## panda (Feb 22, 2020)

Michi said:


> I’d be interested in hearing why you think so, despite a large number of reputable makers seeming to think that it is a good steel.


Awful feel on stones


----------



## Michi (Feb 22, 2020)

panda said:


> Awful feel on stones


That doesn’t make the steel trash, in my opinion 

SG-2 isn’t as nice to sharpen as carbon, but I don’t think it’s that bad. Nicer than either VG-10 or ZDP-189, in my experience.


----------



## Barmoley (Feb 22, 2020)

@panda cares about feel on the stones above any other attribute a steel has. Far above, it has to be total crap in edge holding for him to start caring about that. So as long as it can sort of hold an edge and feels good on the stones he is good with it.


----------



## LostHighway (Feb 22, 2020)

Michi said:


> I’d be interested in hearing why you think so, despite a large number of reputable makers seeming to think that it is a good steel.



Actually I find D2/SLD a more interesting question. Barring powdered metal technology (I'm not aware of anyone using that) it is a relatively coarse grained steel with fairly large carbides and relatively low toughness. It has fairly good edge retention but less than great corrosion resistance relative to other high chromium steels. Edge retention is the only area where it out performs AEB-L. On paper SG2/R2, CPM154/RWL-34, AEB-L and Nitro-V all look like better options to me based on how I value knife steel properties yet I don't hear the chorus of detractors to nearly the same degree as with the VG10 pile on. In fact I hear a fair number of positive comments for SLD/SKD11. Is the real world performance better than the tests suggest?

To tie this back to the original direction of this thread SG2 appears to have at least slight slightly better CATRA performance than D2/SLD and 154 CM which are closely clustered, VG10 falls behind those but ahead of A2/SKD12, AEB-L, Nitro-V, O1, and 52100.

Edit: What is the @panda take on non-Hitachi steels like 1095 or W2 (I sort of expect him to find these at least tolerable), 52100 (probably too much chromium), or 26C3?


----------



## panda (Feb 22, 2020)

I like 1095 a lot, w2 indifferent (not as nice feeling as 1095 but not bad either), I like Marko's 52100. Haven't tried 26c3 

One steel that isn't pleasant to sharpen that I don't mind is spydercos cpm-m4 because it has such good performance at everything else.


----------



## madelinez (Feb 22, 2020)

I kind of understand prioritizing feel on stones somewhat, most knives can last a few hours of non stop cutting, so if you don't mind sharpening every day then that makes sense.

Personally AEB-L, RWL-34/CPM-154 and SG2 are the only stainless steels I would recommend. I have one in M398 and no idea how sharpening that is going to go.


----------



## panda (Feb 22, 2020)

madelinez said:


> I kind of understand prioritizing feel on stones somewhat, most knives can last a few hours of non stop cutting, so if you don't mind sharpening every day then that makes sense.
> 
> Personally AEB-L, RWL-34/CPM-154 and SG2 are the only stainless steels I would recommend. I have one in M398 and no idea how sharpening that is going to go.


The only stainless I enjoy is ginsanko. But heiji semistainless offers hassle free experience with the feel of carbon, best of both!!


----------



## LostHighway (Feb 22, 2020)

panda said:


> The only stainless I enjoy is ginsanko. But heiji semistainless offers hassle free experience with the feel of carbon, best of both!!



Thanks for your response. I'm a little surprised at your relative enthusiasm for Ginsanko/Gin3 given that it is quite close to AEB-L and Nitro-V on paper. Personally, I'm not big on work horse knives but perhaps I need to try a Heiji semi-stainless.


----------



## panda (Feb 22, 2020)

LostHighway said:


> Thanks for your response. I'm a little surprised at your relative enthusiasm for Ginsanko/Gin3 given that it is quite close to AEB-L and Nitro-V on paper. Personally, I'm not big on work horse knives but perhaps I need to try a Heiji semi-stainless.


Oh I'm not a fan of heiji grind at all, but I just regrind it myself because the steel is so damn good, even the cladding is good!!


----------



## LostHighway (Feb 22, 2020)

madelinez said:


> I kind of understand prioritizing feel on stones somewhat, most knives can last a few hours of non stop cutting, so if you don't mind sharpening every day then that makes sense.
> 
> Personally AEB-L, RWL-34/CPM-154 and SG2 are the only stainless steels I would recommend. I have one in M398 and no idea how sharpening that is going to go.



Perhaps as my sharpening skills improve feel on the stones will start to matter more to me. At this juncture I don't value edge retention very highly (home cook, rarely for more than two), even Shirogami 2 is fine for my purposes in that regard. I do, however, value toughness. My list of preferred stainless steels is nearly the same as yours although I would add Nitro-V and place SG2 a notch below the others. I have not yet owned a Ginsanko/Gin3 knife so that is a subject for further research. NioMax will be of interest if/when it comes to market.


----------



## madelinez (Feb 22, 2020)

I've never tried Nitro-V but I assume it's very close to AEB-L so I'd agree with that. After being a blue fanatic for so long I've started enjoying White/SC125 a lot more mainly because of how nice they are to sharpen. I do a lot of chopping versus slicing so toughness is somewhat important but the only knife I own that microchips is a super blue at 65 hrc.


----------



## Kippington (Feb 22, 2020)

madelinez said:


> I've never tried Nitro-V but I assume it's very close to AEB-L


There's a noticeable difference between the two, while making knives at least. On the stones I like the glassy feeling of Nitro-V better, but it seems to be a bit more finicky in the HT. I can't get AEB-L anymore, so comparison doesn't matter to me so much now.
Hardened Nitro-V on a coarse belt behaves very strangely... it shreds into long hairs, in a way I've never seen before.


panda said:


> One steel that isn't pleasant to sharpen that I don't mind is spydercos cpm-m4 because it has such good performance at everything else.


My supplier has CPM-M4 on sale... hnnnnnggggg
I can't imagine it would be easy to forge though...


----------



## Kippington (Feb 22, 2020)

There's a YouTuber that goes by the name "Cedric & Ada Gear and Outdoors" who tests steel by cutting sisal rope. He graphed all his results here: https://docs.google.com/spreadsheet...L9yUHhUmDLAP1hJ1dN_0q5G4tug/edit#gid=43566811
Take it for what it's worth... it might be interesting to some people in this thread.

A cool thing to note: Most of the knives in his tests were factory made. He tested a W2 steel knife that was done by a custom maker, and it did surprisingly well considering how simple the steel is.


----------



## Barmoley (Feb 22, 2020)

@Larrin compared results of Cedric and Ada tests to CATRA as well as Ankerson and other and correlation of all was very high https://knifesteelnerds.com/2019/02/11/can-catra-predict-rope-cutting-performance/.


----------



## inferno (Feb 23, 2020)

i found this rope cutting test interesting. he uses thick manila rope. and after only 5-10 cuts the edge is finished.

i can find manila, hemp, sisal, jute rope.
manila and hemp is about 15€/meter though for the thick stuff. 32-36mm
sisal only goes up to 16mm
jute i can find in 30mm+ for cheap. about 30€ for 15m

would any of these fibers be worse or better than the others?

I would like to avoid the thin ropes because then you end up doing several hundred cuts even for a global (since the blades/edges are so thin, compared to other regular knives).


----------



## inferno (Feb 23, 2020)

also guys, where does one draw the line of "not sharp" anymore?

i just put a shapton 220 edge on a fiskars, no strop, no nothing. and it slices thin notebook paper cleanly...
now most people would not regard a 220 grit edge as particulary sharp.

so having the point where it stops slicing paper as the reference for dull might be a bit optimistic? or? for kitchen use i mean.


----------



## panda (Feb 23, 2020)

Neither rope or paper is food.


----------



## Michi (Feb 23, 2020)

inferno said:


> so having the point where it stops slicing paper as the reference for dull might be a bit optimistic? or? for kitchen use i mean.


To me, it's dull once I can't effortlessly cut through the skin on a tomato, chilli, or bell pepper anymore.


----------



## Larrin (Feb 23, 2020)

There are several dulling mechanisms for knives including wear, edge rolling/deformation, chipping, and corrosion. Slicing of abrasive materials seems to follow similar trends regardless of whether it is cardboard, rope, or CATRA paper. Despite the fact that push cutting does better with polished edges and slicing edge retention does better with coarse edges, the trends for wear are the same that I have looked at. There may be some finer details that aren’t well tested but overall trends are similar. Now if your knife is dulling by one of the other mechanisms then it doesn’t matter which wear test you are doing. You need to change the steel, heat treatment, and/or edge geometry to make sure you are losing sharpness to wear instead as that will last much longer than rolling or chipping.


----------



## inferno (Feb 23, 2020)

panda said:


> Neither rope or paper is food.



no but my tomatos is probably very different to your tomatos, and i could even get 2 tomatos from the same lot that are different.
the variation is too wide with food to make it usable in some kind of test.


----------



## inferno (Feb 23, 2020)

Larrin said:


> There are several dulling mechanisms for knives including wear, edge rolling/deformation, chipping, and corrosion. Slicing of abrasive materials seems to follow similar trends regardless of whether it is cardboard, rope, or CATRA paper. Despite the fact that push cutting does better with polished edges and slicing edge retention does better with coarse edges, the trends for wear are the same that I have looked at. There may be some finer details that aren’t well tested but overall trends are similar. Now if your knife is dulling by one of the other mechanisms then it doesn’t matter which wear test you are doing. You need to change the steel, heat treatment, and/or edge geometry to make sure you are losing sharpness to wear instead as that will last much longer than rolling or chipping.



what about plastic rope? i'm thinking this could be very destructive to high carbide steels.


----------



## Chuckles (Feb 23, 2020)

> pineapple skin



This was the last fight I had with my Kato and when I realized we had to break up. Horrible. 

I think Larrin is right about making sure you know what is the cause of poor cutting. Rolling and micro chipping are more prevalent in kitchen knives than is assumed in my opinion. A mix of sub optimal technique, hyper thin edges and wire edges makes retention info based on steel wear resistance claims dubious to me unless I have personally used the sharpening work of the person making the claim or somebody I trust vouches.


----------



## Kippington (Feb 23, 2020)

Michi said:


> To me, it's dull once I can't effortlessly cut through the skin on a tomato, chilli, or bell pepper anymore.


Same here.
If I gently touch the edge and can feel the knife biting into my skin, I know its sharp and good enough for work in the kitchen. If it's too blunt, or polished super-sharp, I won't be able to feel the bite and wouldn't like using it on the board.

It can be fun to mess about with polished silly-sharp stuff _*off*_ the board though...


----------



## vicv (Feb 23, 2020)

Yes I consider when it's no longer 3 finger sticky that is stolen needs to be sharpened. I will disagree though that a 220 grit Edge has a very sharp. It's just as sharp as a 10,000 grit edge if they were both sharpened correctly. The ten thousand grit Edge will be at a higher polish but it will not be any sharper.


----------



## panda (Feb 23, 2020)

Chuckles said:


> This was the last fight I had with my Kato and when I realized we had to break up. Horrible.
> 
> I think Larrin is right about making sure you know what is the cause of poor cutting. Rolling and micro chipping are more prevalent in kitchen knives than is assumed in my opinion. A mix of sub optimal technique, hyper thin edges and wire edges makes retention info based on steel wear resistance claims dubious to me unless I have personally used the sharpening work of the person making the claim or somebody I trust vouches.


example, take two identical knives. have chuckles sharpen one, and i sharpen the other one. i bet you quite a few people would be able to notice a difference purely from variation in peoples sharpening techniques. for example, my technique is very raw and not refined at all, quick n dirty. chuckles is the opposite.


----------



## Luftmensch (Feb 24, 2020)

inferno said:


> also guys, where does one draw the line of "not sharp" anymore?



It depends on what you want to do! But in the kitchen....



Michi said:


> To me, it's dull once I can't effortlessly cut through the skin on a tomato, chilli, or bell pepper anymore.



This is my litmus test!


But really.... an acute angle behind the edge on a hard steel with a laserish grind can be a bit like the Duracell bunny in a home kitchen.





panda said:


> Neither rope or paper is food.



Dont be naughty! 





inferno said:


> what about plastic rope? i'm thinking this could be very destructive to high carbide steels.



It does not matter what material you choose to cut so long as the material is consistent between tests (as you point out). The decision amounts to changing one constant. I also doubt (by and large) it matters how much wear it imparts on the knife. You will either make more cuts to reach some end point or less. From the testers point of view, you may as well choose a more difficult material (within reason) so that you need to perform less cuts. Plastic is repeatable and cheap.

On that 'end point'.... going back to



inferno said:


> where does one draw the line of "not sharp" anymore?



That barely matters either - so long as it is measurable. Your goal is to quantify 'edge retention' by exposing a maximally sharp knife to constant wear until it reaches some lower sharpness (or bluntness) threshold. Again you will want to choose a test that is sensitive and repeatable enough to reliably illuminate the difference between knives in a manageable number of cuts. Of course... you'll probably have to hand wave the observer effect away


----------



## inferno (Mar 7, 2020)

i got some polyethylene fake hemp rope 36mm. sharpened up my fiskars beater. its some krupp low carbon crap SS at 52hrc. took it to 4k on glass.
after about 30 cuts it started to tear paper in one spot. and after 70 cuts its tearing for the entire front half. but you can still make it cut clean if you know how to cut paper cleanly.
i'm thinking the edge is rolled more or less. either way 70 cuts with the shittiest steel is not good for testing. since this could translate to 700-7000 cuts with good steel. 

i just sharpened up my handleless (it cracked during the last test) r2 kurosaki on the 4k. we'll see how it goes. i only got 5m rope and i have feeling i could be running out of rope soon.
i have to get some natural rope.


----------



## VICTOR J CREAZZI (Mar 7, 2020)

inferno said:


> i got some polyethylene fake hemp rope 36mm.


I have a polyester secondary on one of my razor strops that is the most aggressive fabric strop that I have ever used. I wondered what could make polyester so abrasive. Then I read that fumed silica is often used to thicken polyester resin. I would assume that the amount of fumed silica would vary quite a bit from different manufacturers, products, runs, etc.

Edit; Just noticed that you said polyethylene and not polyester. I don't know if fumed silica is used in polyethylene fiber, but it certainly wouldn't surprise me.


----------



## inferno (Mar 7, 2020)

i tested an r2 blade. and it managed 142 cuts then i simply ran out of rope, 5m sounds much but its not that much really. and it was about 85-90% as bad as the fiskars at 70. probably could have gone 160 or so really. 

gonna get natural rope and see what happens. preferably i would want the fiskars to get dull at 10 or so cuts. so i dont have to do this all day long.


----------



## inferno (Mar 7, 2020)

yeah this plastic poses no problems i'd say. for any steel.


----------



## Barmoley (Mar 7, 2020)

Tape around 20-30mm of the blade and just cut with that portion of the edge. Or did you do this already?


----------



## inferno (Mar 7, 2020)

no i just sawed through, but for this to happen you have to use maybe 1/3 of the blade pretty much. so its the same for all knives i guess.


----------



## Luftmensch (Mar 8, 2020)

inferno said:


> i got some polyethylene fake hemp rope 36mm. sharpened up my fiskars beater. its some krupp low carbon crap SS at 52hrc. took it to 4k on glass.
> after about 30 cuts it started to tear paper in one spot. and after 70 cuts its tearing for the entire front half



Nice of you to document it for us!


----------

