3 finger sharpness test explained from cartercutlery.com

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MadRookie
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#21

Post by MadRookie »

Lol

:)
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#22

Post by jackknifeh »

Evil D wrote:For that matter if you have very thick calloused skin, you may not feel the same sensation, and perhaps could even take very light cutting before you would ever feel pain or see blood. I have all the respect in the world for Murray and will bow to his superior sharpening skill, but I just don't believe in this test for sharpness. There must be more controlled ways with far less variables.
MadRookie wrote:You echo my sentiments exactly!

:)
Revival wrote:Exactly! Its not something I want to experiment with either.
This is completely true. I don't think we are questioning sharpness. Just the exact use of the test. I think the different condition of people's skin as Evil mentioned could play as big a part in any sensation felt as the sharpness of the edge. I have decided to send the knife that a forum member gave me to Murray to sharpen. It will then be an edge that passes his test. When I get it back and do the test that will show me a lot I'm sure. This knife has M4 steel and takes as good an edge (when I sharpen it) as the GB and holds it. I hope to get back a knife with an edge sharper than I have seen. To be 100% honest I'll be surprised if there is a huge amount of difference in his edge and the one that was on the same knife when I got it. The sharpness on the edge of this gift knife was as sharp as I've seen, ever. Other's have been competative but none sharper. I may spend $15 to learn the test results are like the hanging hair test. Everyone's results are different and need to be judged based on the individual's skin. When we know the condition of an edge and then perform the 3 finger test we learn how a dull, semi-sharp, hair whittling sharp, etc. edge feels to our fingers. Then the test can be used. Sounds funny though because for this to be the case we need to already know the condition of the edge so why would we need another test? And a test that requires practice with edges we already know the condition of seems to be of little use. Anyway, I'll have enough info when I get the knife back to answer these questions. I'm going to learn something. Either I'll have an edge that passes the test and I then understand what Murray is talking about. Or,,, I'll learn we have spent too much time concerning ourselves with a test. :)

Jack

PS
I sharpened the knife I'm sending as best I can. It slices phone book paper with as much ease as any knife I've ever sharpened. After using the Shapton glass 8k I did a couple of push strokes on the Spyderco UF stone. I just love the feel of the Spyderco ceramic stones. Especially the UF. I just wanted to record how I sharpened this knife. I may not be able to remember in the future. Memory isn't even as sharp as my knives any more. :)
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Got a reply back from Murray Carter

#23

Post by jackknifeh »

Here is an email I got from Mr. Carter today. These are his comments on the knife I sent him.


Hello Jack,*

I took a close look at the knife you sent and my two observations are that:

1) You had a micro-bevel on an otherwise well sharpened well polished primary edge (micro-beveling degrades primary edge sharpness)
2) The secondary edge is extremely rough, from both lateral scratches and etching

Keep in mind the primary edge initiates the cut, but the secondary edge allows the blade to be pushed through the medium being cut. I started to polish one side of the secondary edge and left just enough lateral scratches so that you can see what I'm mentioning. You will need to spend some time polishing the other side. Smooth polished secondary edges make an incredible difference in the cutting experience. I feel the steel in this blade can either pass the 'Three Finger Test' or be sharpened to shave, but not both. I believe that the tungsten and vanadium in the steel prevent it from having super fine carbides, like the carbides in White Steel #1.

Sincerely,*

Murray Carter.



I had some thoughts about the reply and replied to his message with what I put below


Thank you Murray,

This is exactly what I was hoping for in addition to getting back a knife that is really sharp. However, I think I have had a different understanding of the edge and blade regarding the terms you use. Here is how I would describe the blade and edge on the knife I sent you. The micro bevel you mention I was calling the primary edge. The polished bevel area that I believe you referred to as the primary edge, I was calling the secondary edge or bevel. My goal here is to thin the blade (secondary bevel) near the edge so it cuts better. I also like to polish the secondary bevel to provide a smooth surface which hopefully creates less resistance when slicing/cutting. The micro bevel was to strengthen the edge against chipping and anything else that will damage the edge. Or, on the micro bevel I might use a coarser stone for a coarser edge rather than a smoother one. The knife I sent you I would use as a work knife and keep it in my tool box
on in my tool belt. If I were to plan on using a knife for less stressful tasks I would not have added the micro bevel. In that case I would describe the polished edge/bevel as the primary edge and there would not be any secondary edge or bevel at all. But it seems according to your terminology I have a secondary bevel (which I call the grind) and a primary bevel that is polished (which I called the secondary bevel) and then a micro bevel (which I call the primary edge). The rest of any blade I have been calling the grind. That knife has a full flat grind blade. Other knives have grinds like hollow, saber, etc. It seems to me you are calling the largest portion of the blade, which on this knife has some sort of electric etching put on it to reduce reflection. I don't remember the exact process. I have been considering removing that to expose bare steel which would hopefully reduce resistance when cutting. Does this make sense to
you? Am I understanding your terms the way you mean them and do you understand how I describe a blade? I want to make sure I understand what you are talking about when using the terminology you use. Would you say using the terms "primary edge" and "secondary edge" are industry standard way to refer to an edge? I always thought there would be a standard but haven't heard of one or seen any standard in writing. Even different books from different authors have different terms.

I still don't understand the 3 finger test because of what you said about an edge passing the test OR shaving but NOT BOTH. This has me completely confused. The only thing I can determine from the 3 finger test is how smooth or coarse the edge is. If someone hands me two knives and they will both slice news print easily I can use the 3 finger test to know if the edges are toothy or smooth. But I would only want to shave with the smooth one. Understanding and performing the 3 finger test is a minor point compared to getthing the edge sharp I suppose. I just can't grasp what it is that you determine when you do it. To me the coarse, very sharp edge will not allow my skin to slide along the edge. But then again neither would a hacksaw blade. When I get the knife back would you say the edge should pass the test or not. Should the edge shave? The "pass the test or shave but not both" really confused me.

I wanted to say I appreciate you leaving the edge or bevel with a scratch pattern so I can better understand what you are talking about. When I see it I am sure things will be clearer.

Thanks for your help and I appreciate your time.

Jack


I should get the knife back in a few days. Definately looking forward to seeing the edge. Cutting with it as well. :D

Jack
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#24

Post by jackknifeh »

I think a "micro-bevel" is a common way to sharpen an edge around here. I wonder if this has become a trend because the different type blade steels in production knives, meaning some are not as high quality as the steel Murray Carter uses require a bit of strengthening at the edge. So we micro-bevel. The white steel he uses primarily may not require this. Depending on use I assume. He did seem to indicate the blade steel (M4) on the knife I sent him would hold up to use without a micro-bevel.

Another reason I have gotten used to using a micro-bevel is because it makes touch-ups very quick and easy. Living and learning (I hope). :)

Jack
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#25

Post by paladin »

jackknifeh wrote:I think a "micro-bevel" is a common way to sharpen an edge around here. I wonder if this has become a trend because the different type blade steels in production knives, meaning some are not as high quality as the steel Murray Carter uses require a bit of strengthening at the edge. So we micro-bevel. [...]

Jack

Maybe I'm wrong, but I think micro-beveling is pretty standard as well. I microbevel to insure that I pare down the wire edge that I am prone to forming. Mr. Carter's skill set probably precludes wire edge formation.

From what I've watched of M. Carter, (I think) he calls the primary bevel what most people would call the "cutting edge."

And if I'm correct, what he calls the secondary edge is what I would consider the blade body itself, or at least, the most immediate blade section transitioning from the "cutting edge."
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#26

Post by jackknifeh »

paladin wrote:Maybe I'm wrong, but I think micro-beveling is pretty standard as well. I microbevel to insure that I pare down the wire edge that I am prone to forming. Mr. Carter's skill set probably precludes wire edge formation.

From what I've watched of M. Carter, (I think) he calls the primary bevel what most people would call the "cutting edge."

And if I'm correct, what he calls the secondary edge is what I would consider the blade body itself, or at least, the most immediate blade section transitioning from the "cutting edge."
I like the term "edge-bevel" to reference the cutting edge, edge apex, etc. because the word edge is in the term. Everything else IMO should be referred to as a bevel or grind. Just my opinion. It sounds to me like you think about the edge like I do. I think about it in steps from edge to spine. The edge apex could be called a primary edge, micro-bevel, or edge bevel. The next section, at a lower angle I like to call it the back bevel (Spyderco's term I believe). Then you could have more than one back bevel but let's leave that out for now. After the back bevel (or secondary bevel) I call the rest the grind or blade. The differences in terminology make it a bit difficult to understand what each of us is referring to when we use terms others are not familiar with. I don't see any "standard" knife terminology in the near future. This would require a commitee of knife guys to get together to decide on a "proper" way to refer to different parts of a blade or knife. I'd say this is already done regarding the entire knife but the edge is not covered.

Oh well. :)

Jack
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#27

Post by MadRookie »

While I have the greatest respect for Murray, I tend to disagree with this comment from him....

"(micro-beveling degrades primary edge sharpness)"


I quantify by saying:

1. Sharpen a knife with NO micro-bevel to 15 dps....
2. Sharpen an identical knife to 12 dps, then add a 15 dps micro-bevel......

IMHO there is absolutely no difference at the very edge of the edge - both are at the same included angle, meaning both have the exact same amount of steel within the 15 dps angle - thus having equal strength, as well as sharpness.

The difference with 2 is that this knife will perform better than 1, as it is thinner behind the 15 dps cutting edge.

What am I missing??


:confused:
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Case pocketknife, small stockman with amber bone handle

#28

Post by jackknifeh »

MadRookie wrote:While I have the greatest respect for Murray, I tend to disagree with this comment from him....

"(micro-beveling degrades primary edge sharpness)"


I quantify by saying:

1. Sharpen a knife with NO micro-bevel to 15 dps....
2. Sharpen an identical knife to 12 dps, then add a 15 dps micro-bevel......

IMHO there is absolutely no difference at the very edge of the edge - both are at the same included angle, meaning both have the exact same amount of steel within the 15 dps angle - thus having equal strength, as well as sharpness.

The difference with 2 is that this knife will perform better than 1, as it is thinner behind the 15 dps cutting edge.

What am I missing??


:confused:
I agree with you. Now, I don't have even close the experience of you or Murray but what you say makes sense. I've always thought the micro bevel is for creating the edge that will hold up to the intended use of that knife. That's the primary bevel as I have always seen it. Then the secondary (or back) bevel is at a lower angle to improve cutting. But like the primary or micro bevel this can be very very thin for cutting vegetables or needs to be thicker for a camp knife. Still, the intended use is the key. But, just the micro-bevel having a higher angle will degrade cutting performance (on paper or in the lab). Just because it is a higher angle it wouldn't cut as well as if the micro bevel weren't there and the angle was the same as the angle just above it. Still, like you say a micro bevel angle can be just as "sharp" at the apex as any angle even if a higher angle does degrade cutting performance.

I also think that communicating in a forum setting is not as good as if we were standing there looking at each other. He said a micro bevel "degrades primary edge sharpness". Since I sent him a knife I sharpened and know what bevels are on it I have a better idea (I think) of EXACTLY what he is referring to when he says "primary bevel" or secondary bevel" or "micro bevel". So keep in mind what I would have called the "primary bevel" on THAT knife, he is calling a "micro bevel". What I call the secondary bevel (polished bevel above the micro bevel) he is calling the "primary bevel". I "think" on the knife I sent him he is calling "what I call" the secondary edge bevel the primary edge. So, by putting a micro bevel on the "primary edge" (as he calls it) it would degrade cutting performance a tiny bit but not sharpness right at the apex. So, maybe he was talking about cutting performance being degraded and not sharpness at the apex. I'm thinking this because when communicating in a forum some of the exact meaning (in our minds) is lost in the words we use because we don't see how the guy is holding a knife (body language), facial expressions, and most importantly, we can't stand there and say "don't you mean cutting performance instead of sharpness?". Instead, it takes me 10 minutes to type this post then wait for a response. In addition to that we are discussing what Murray said and he isn't in on this particular conversation so he can't clear up his exact meaning or misunderstanding (if there is one). I'm hoping he will reply to my email reply regarding the "wording" differences in how he discusses a knife edge and how I picture it.

I also have in the back of my mind that all of the knives he makes have one of two of the "better" steels available for knife blades. I suppose AUS-8 may be the "better" steel for a knife blade in some situations than white steel but that's another discussion. So, maybe the steel he uses can hold up to an edge apex at a lower angle than a blade with VG-10. This is what I've been seeing when talking about different steels at different edge angles since I have been on this forum or learning about sharpening. OTOH, if that's true the bevel right above the primary edge could be lower as well. But then we would be talking about blade strength and not just the strength of the edge apex. Again, another subject and discussion probably.

Many times in several different fields I've seen some of the guys who have been doing it for a long time end up sticking with a very basic system for performing their skill. This is after all the learning and playing around that may be required for the learning process. Using the EP I put an edge bevel of 40 inclusive on an Endura. Then I put back bevels of 36, 32, 28 degrees creating a convex edge with flat bevels instead of one round smooth bevel. Doing this did not improve cutting performance but I did it. I learned I could then smooth the flat bevels with a strop making it easy to put a convex edge on the blade with the EP and then stropping (or leaving it as is). But now that I've done it, learned and I understand it, I may not ever go to that trouble again. Or, maybe I will. :)

These forum discussions are great and 100% better than no discussion at all. But having the discussions in person would be 100% better than the forum discussions. That means in-person discussions are 200% better than no discussion? :confused: :) Never was good calculating percentages. :)


Jack
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#29

Post by jackknifeh »

I just looked in the "show those edges" thread. In post 603 Donut questions the exact issue of what do you call a micro bevel when you stick it on the primary edge bevel. Depending on who answers that question will determine what terms are used to describe this situation. See??? terminology needs to be understood. After we ask questions and get answers we do understand what we are talking about. But what about all the people not on this forum or did not read that particular thread (or post)? THey still have the same questions and/or different answers from whoever they do ask. There is no "standard" list of knife edge terms regarding describing different bevels or aspects of the edge. I guess that would be too easy. :)

Jack
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#30

Post by jackknifeh »

Got the knife back from Carter Cutlery today. I am happy to say I now know what an edge feels like that PASSES the three finger test. What is Murray's explanation of passing? Best I can remember is he says "your brain will tell you that if you slide your fingers you will be cut". Yes, I can still slide my fingers along the edge IF I apply significantly less pressure than ever before. If I applied the same amount of pressure that I have been applying (which always has been a very light amount by my standards) and slid my fingers, guess what? Blood. No kidding. I think this is the sharpest knife edge I've ever felt. I will not put it through any sharpness testing for a couple of reasons. The most important is I don't have the equipment to be able to get results that can be translated into numbers. If my GB is sharpness of 8 and this knife is sharpness of 9, AND WE ALL KNEW WHAT 8 AND 9 CUT LIKE you could imagine a difference. I can't do that. The other reason I won't do any sharpness testing is if I cut anything with this knife it will be every day use. I'm not wasting sharpenss on tests. I know it is sharper than anything I've ever sharpened or seen. I have seen some very sharp Spyderco's. This knife came from the maker VERY sharp. And IMO I have gotten some knives VERY sharp when I really focus and a little luck. This one is sharper. I'll try some numbers though. The average pocket knife someone hands you is a 5 out of 1 - 10 and I'll call this knife a 10. Mine are 8 - 8.5. This knife came to me at a 8.5 - 9. Most Spyderco's come with a sharpness of 7 - 8.5. I'd say that's accurate with the knives I've felt (give or take .01 :) ).

There is no micro bevel on the edge. The one area that I called the secondary bevel (back bevel) and the primary edge (micro bevel) are now one bevel. That makes the whole bevel the primary edge which is how I expected it to come based on his comments on my edge. I know he sharpened the entire bevel because the scratch pattern is there. When I sent it to him it had a mirror polish to the naked eye. Slight magnification revealed scratches but now there are easily seen scratches. He says he uses 1k and 6k stones. I'd say he only used a 1k stone if only a 1k and 6k are available to choose from. Then again I'm comparing this edge to the scratch pattern left by Shapton glass stones. He uses Japanese stones and I believe they are King stones. Could be wrong about that though. He says he uses what he sells and Ibelieve he sells King 1k and 6k. Given my lack of much experience with the 3 finger test I can feel some teeth. But, even if this edge passes the 3 finger test it is possible to "touch" the edge and slide your skin. But the amount of pressure I feel comfortable with using is much different. I won't use this edge for a while only because I want to keep it as a reference for a 3 finger test role model. I'd like to get the hang of using this test now that I know what an test passing edge is like. Don't get me wrong. This edge is not head and shoulders sharper than other very sharp knives but I'm impressed. Definately sharper than anything I've sharpened. And it is the sharpest edge I've seen but not by a huge amount. But a little bit of sharpness increase over the sharpest I've seen? Yes! I invested about $18 for shipping to and from and I have my money's worth plus some.

Murray's goal of sharpening one knife for free is to get more business. I won't be sending him any knives to sharpen because my goal is to do it myself. I will recomend him though.

He also removed a coating on one side of the blade that the maker put on this blade. He left a very small spot on that side to illustrate what he did. He mentioned he had done this in his email. Also, he called this the secondary bevel. Meaning what I was calling a FFG he is calling the secondary bevel. So, just count the bevels starting at the apex and you have the idea. If I were to put a micro bevel on this edge I'd say my micro bevel would then be the primary edge. The bevel/edge he put on the knife would then be called the secondary bevel and the rest of the blade could be called the thirdary bevel (or FFG). I guess it's a matter of terminology. Who cares, as long as we are on the same page regarding the edge? Here's the thing. When this edge requires a touch up should I touchup the entire bevel or put a micro bevel on it? Personal choice is the answer. Here's my plan. If the edge holds up to my use with no excessive damage I'll touchup using the entire bevel with no micro bevel. If, OTOH, the edge chips or rolls, I'll put a micro bevel on it. This would increase the edge apex angle and hopefully strengthen the edge some.

So lesson learned here. Mr. Carter is a very accomplished knife sharpener. :) Is anyone surprised? Now I have actually felt an edge to chase instead of just trying to get edges sharper than before. Here's a couple of pics of the blade to show what I have talked about. My camera doesn't take real good close up pics so no pics of scratch pattens or anything like that.

Here is the side with the coating still on the secondary bevel, as he called it. I would have called this area the FFG all the way to the spine.
Image

Here is the side with the coating removed (except for a small spot near the tang). Iwill remove this spot as well as the coating on the other side. I'll remove the coating from the tang area when I decide to disassemble the knife, if ever.
Image.
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#31

Post by Evil D »

Did he mention anything about what degree it's sharpened to? I will say there is a giant difference in feel and perceived sharpness when comparing a low angle edge with no micro bevel to a 30 degree edge with no micro. If he just dropped the edge angle down a bunch and didn't add a micro bevel, I wouldn't be surprised if that's a large part of the difference you're feeling.
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#32

Post by Officer Gigglez »

Not the best method of testing
Spyderco Knives (in order of obtainment):
-Tenacious, Combo edge
-Tasman Salt, PE
-Persistence Blue, PE
-Pacific Salt, Black, PE
-Delica 4, Emerson Grey
-DiAlex Junior
-Byrd SS Crossbill, PE
-Endura 4 Emerson Grey
-Byrd Meadowlark 2 FRN, PE
-Resilience
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#33

Post by jackknifeh »

Evil D wrote:Did he mention anything about what degree it's sharpened to? I will say there is a giant difference in feel and perceived sharpness when comparing a low angle edge with no micro bevel to a 30 degree edge with no micro. If he just dropped the edge angle down a bunch and didn't add a micro bevel, I wouldn't be surprised if that's a large part of the difference you're feeling.
He didn't mention edge angle but it's about the same as it was. I did it free hand so I don't know what it was like I would if I'd used the EP. I think when I did use the EP last time on this knife the back bevel would have been 12 dps. Then I added the edge bevel at about 16-18 dps. The edge angle now looks just like it did on my back bevel so what I think he did was just stroke on my back bevel until he reached the apex. That might make the edge feel sharper with the apex now at 24 deg. instead of 34. I'm looking at it and feeling it right now. Hang on... I'm back. Thanks for waiting. :) I don't know. Still feels sharper than my edges unless maybe if I really focused on ultra light strokes and stropped down to .25 micron on and finished on a roo strop. Even then I don't know. For the past few months my edges are sharper than they have been for about a year. This is using only stones. Then I might refine a bit or smooth a bit with a really high grit strop but the stropping doesn't improve the edge noticable under every day use. Stropping makes the edge a little crisper but how much difference it makes when using the knife is hard to tell. I sliced some phone book paper with this one and it cuts very well.

As I said before, this edge isn't A LOT sharper than it was when I sent it to him. BUT, I can feel a difference when doing the 3 finger test. I have considered how much my brain may be getting in the way. I really think I am looking at this completely un-biased but being human I couldn't swear I am 100% un-biased. I had two feelings when I sent him the kniife. Feeling one: It wasn't going to come back sharper than what I can do. Or, feeling two: It was going to come back sharper and I was going to feel a difference when performing the 3 finger test. I would have felt proud of my edges if Murray couldn't get the knife any sharper than I did. OTOH, I hoped it would come back sharper just to show me what an edge is like from one of the most respected sharpeners there is. Then compare that edge to my ability. After considering all this stuff and examining the edge as best I can I think it is sharper than it was to the point I can tell when paying close attention and cutting things like phone book paper or news print. But how much different it will feel when cutting a stick for the grandkid or something like that time will tell. Wait. Ok, I just sliced some TP. His edge sliced it cleaner than anything I've ever sharpened without a doubt. There is no question here. I don't thing the edge angle would matter much when doing this with the knife with the angle I had on the apex and what it is now. I'm calling it sharper now because of the TP test. No doubt. Raining now but when playing outside with grandkid I usually have to cut him a stick to hit me with. :) I'll try this knife to see how much difference (if any) there is on that type of task.

Since I can't test sharpness any more thoroughly than what I've done I'm of the opinion the edge is sharper because of Mr. Carter's higher skill level. I'm not suprised and doubt if anyone else is either. :D What I will do just for the heck of it is I'm going to take my GB edge down to whatever angle the back bevel is now all the way until that angle apexes. Then see what it feels like.

This thread started only about the 3 finger test, how to do it and what it is supposed to show. I think I have a better idea about that now. There is no way I can communicate this on a forum. I would like to see someone else send him a knife and see what they get back. It would cost $20 max which I don't think is a lot if you really want to see whatever you see. OTOH, that $20 sure could go toward another Spydie! :D And how important is all this? I'm happy with what I see from this experience.

Jack
PS I am going to lower the angle on GB though. Gotta. :D
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#34

Post by Evil D »

I would never say I know more than Murray, not even as much, but I do feel like there comes a point when going beyond a certain level of sharpness is purely for showing off, especially since even the most exotic steels won't hold that high level of sharpness for more than a few cuts.

If anything, I would like to send him one of the Superblue sprints to see what he can do with a Japanese steel since that's similar to what he uses. I would also kill to take one of his knife forging courses but it's a bit out of my price range. I'm still skeptical about this 3 finger thing and feel there are better ways to test for sharpness, because at some level I think that voice in your head will stop you from cutting yourself even if you haven't reached the level of sharpness that Murray reaches. Another thing is he's a strop user, so that by itself will give you a sharper feeling edge in some cases, but you know my issues with strops so if that's the difference between his edge and mine then I'll stick with my edge.
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#35

Post by Qcrazy »

Thanks for the thread and thought provoking information. As to the three finger test....I'm out, it's so dry(humidity) here in Colorado right now that the cracks in my fingertips are more than I can stand. I don't need to screw up and cut myself.
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#36

Post by jackknifeh »

jackknifeh wrote: PS I am going to lower the angle on GB though. Gotta. :D
Worked on my GB last night for a couple of hours. I kept the back bevel angle at whatever it is, probably 12° per side but I started with a 320 grit Shapton glass and continued at that angle until the edge apexed. Then the 1k and 4k. At this point I had a very pretty primary bevel of 12° per side approx. that apexed. The bevel is a bit convexed of course. I then raised the angle a fraction of a frog's hair (industry term) to finish the edge. I have to say this edge is very sharp and actually it does challenge Mr. Carter's edge in sharpness. Murray's edge still has an extra bit of crispness to it. Upon close examination with a 30x and 60x loupe mine is smoother (bevel and edge). Wish I had more magnification. The 3 finger test is a test that I don't put much stock in for anything other than determining the toothiness of an edge. I can tell the difference in an edge finished with a 1k stone and a 4k or higher grit stone. But I can't tell which edge will cut better. I'm thinking that it's not a test to measure different sharpness levels among sharp knives. Just a pass/fail test. Maybe with more practice using the 3 finger test but there are other ways to determine sharpness so the need for this test is a personal choice. Having said that I'm going to continue to do it on every knife I pick up (unless I forget) just out of curiosity. Maybe I'll understand the test one day. The only reason I'm going to continue to even think about this test is because Murray Carter seems to value it so highly. It's a given he knows 100 times more than I do about knives and edges. I'll keep doing it out of curiosity.

MICRO-BEVEL
MR gave the best comments on a micro bevel I think. The edge angle needs to be high enough so it is strong enough to not chip, roll, etc. under the use of the knife. The angle will be dependent on the blade steel and intended use. But a lower angle just above this to keep the blade thin will provide better cuttin performance. This can be accomplished with an EP, WE and other systems leaving a very defined angle change line. But if you free hand sharpen your bevels will not be as flat and the angle change will be gradual. Even if you try your best to keep the angle the same free hand sharpening will always leave the edge a little bit convexed. So, since the angle at the edge apex and the angle at he top of the bevel (primary edge) is lower can we consider this a gradual micro-bevel? I'm not talking about the edge as much as I am the words we use to describe the edge.

To create the best edge for the use of a knife I think a high enough angle to keep the edge strong followed by a lower angle to keep the blade as thin as possible and still be strong enough for the intended use is best. The blade on a camp knife needs to be thicker and stronger than the blade on a fillet knife. On the knife (FFG) I sent him he calls the slightly convex bevel/edge the primary edge and there is no seperate micro-bevel. Let's assume this is perfect for the knife's intended use. If I were then to put a micro-bevel on the edge 5 degrees higher that would degrade the overall cutting performance of the knife. A little bit. For a pocket knife or a work knife it can be argued this is wise because you never know what the knife will be required to cut. But for a fillet knife for smaller fish and smaller bones a single primary edge with no micro-bevel is best. An increase in edge angle from a micro-bevel would degrade cutting performance. Would it degrade it enough to notice easily? Don't know. That would depend on the skill and attention to detail of the knife user. A sushi chef might be able to tell a difference. The average lumber-jack probably would not notice. :)

Sending the knife to Murray was one of my better ideas. If anyone wants to improve their sharpening skill until no more improvement can be made by the normal human I recommend sending a knife to Mr. Carter like I did. I don't think his offer for the first sharpening to be free is to assist other's in their improvement. I think it is to demonstrate his ability in hopes of getting more business. OTOH, knowing his ability would prompt me to buy his two DVD's on sharpening knives if I were just getting started. I think that $70 would be well spent. Better that possibly than a lot more time figuring everything out for yourself. The forums are a godsend for help and I've learned no telling how much here. The DVD's may answer most of the questions we have and answer them with pictures also. Something tells me if someone wants to start learning to free hand sharpen knives his DVD's would be a wise purchase. The two Japanese water stones would also be a good investment I'm sure. I don't know they would be a better choice than the Spyderco stones though. I use them and swear by the quality and performance of Spyderco's sharpening tools. Then again, compared to people of Murray's experience I'm a newbie. Even so, I stand on my admiration for Spyderco's fine and UF ceramic stones.

Jack
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jackknifeh
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TP cuts

#37

Post by jackknifeh »

Here is a piece of TP that I sliced with the knife Murray sharpened and my GB a few minutes ago. Mine is on the left and Murray's is on the right. His is a little cleaner. Plus mine looks like the path of a drunk driver. :)

Image

Jack
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#38

Post by jackknifeh »

I want to stop talking about this because I'm beating the dead horse. So as a final thought on the terminology Murray uses for his knives I stumbled on this while looking at a knife I will dream about for a long while.

Here are the specs on one of his knives. What he has listed as "SECONDARY:" is flat. This is what most people that I'm familiar with would call the grind. FFG in this case. I wonder if he makes any hollow grind knives and if so how does he describe them? He did include a really great "gittin" book of his knives. I'll check it to see if any of his knives have different grinds.

STYLE: Neck Knife, Pipsqueek Model
STEEL: White Steel
FINISH: Forge Finish, Unpolished
SECONDARY: Flat
HANDLE: Mammoth Teeth Composite
PIN: Mosaic center pin
LINERS: Thick Black
OVERALL LENGTH: 132mm (5.2")
WEIGHT: 34grams
BLADE LENGTH: 67mm
BLADE THICKNESS: *2.2mm
SHEATH: Kydex Neck Sheath
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MadRookie
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#39

Post by MadRookie »

Nice report - stop cutting **** paper when you are full of alcohol.....!!!


;) :D :p :eek:
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