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A Bit Disenchanted With CPM 440V
- Thread starter Coonskinner
- Start date
- Joined
- Jun 6, 2000
- Messages
- 3,625
Jeff, I have tried my Military at two angles with a variety of grits/hones.
I found that the flat white stone (step 4) at 20 degrees per side gave me a very good edge with a long life for cutting boxes etc. The knife always felt blunter than the actual performance suggested
. Thus I tried a DMT Fine stone and the cutting became more aggressive and less able to shave! The edge did not feel like it was holding up quite as well, but that is hard to prove on one sharpen.
I recently went to a thin 15 per side and honed on my Ultra Fine ceramic Benchstone from Spyderco. The edge is very sharp and cuts very well, but perhaps still not a great 'straight razor edge' on arm hair shaving. I am a little concened about edge strength at this angle, but as a defensive knife I wanted max sharpness for obvious reasons!
My feeling is the step 4 on the white stones at 20 per side felt about right for me. I had not tries it at step 3, perhaps Sal is correct on this. That is my next choice, when I need to re sharpen this knife or when my Starmate needs a bit of work.
I gave my new Starmate a free hand pass or two on the Ultra Fine and found the blade now shaves very well at 20 per side
???? This is getting a bit odd... The sharpen was to touch up and improve the FACTORY edge, this knife had only had a little use right at the tip.
Perhaps, I will use my DMT stones to 'freshen' up the Military next time round and remove a bit more material?
This 'steel' is the ONLY material I have yet to understand perfectly when it comes to getting 'the' edge. Perhaps, part of the problem is what each of us considers a 'shaving' sharp edge to be? My arm hair is few and far inbetween as I test on my arms so much, thus the knife has to be VERY sharp to get some hair. If however you had arms like Cheewbacca or Sal in the Sharpmaker vid, my Military would remove a HUGE amount of hair. Another point is how are we shaving? I hold the knife at about a 15 degree angle and push it lightly along the skin, do some of you scrape the skin, holding the edge down?Pulling the blade up and down? No one has ever thought of this...
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
I found that the flat white stone (step 4) at 20 degrees per side gave me a very good edge with a long life for cutting boxes etc. The knife always felt blunter than the actual performance suggested
I recently went to a thin 15 per side and honed on my Ultra Fine ceramic Benchstone from Spyderco. The edge is very sharp and cuts very well, but perhaps still not a great 'straight razor edge' on arm hair shaving. I am a little concened about edge strength at this angle, but as a defensive knife I wanted max sharpness for obvious reasons!
My feeling is the step 4 on the white stones at 20 per side felt about right for me. I had not tries it at step 3, perhaps Sal is correct on this. That is my next choice, when I need to re sharpen this knife or when my Starmate needs a bit of work.
I gave my new Starmate a free hand pass or two on the Ultra Fine and found the blade now shaves very well at 20 per side
Perhaps, I will use my DMT stones to 'freshen' up the Military next time round and remove a bit more material?
This 'steel' is the ONLY material I have yet to understand perfectly when it comes to getting 'the' edge. Perhaps, part of the problem is what each of us considers a 'shaving' sharp edge to be? My arm hair is few and far inbetween as I test on my arms so much, thus the knife has to be VERY sharp to get some hair. If however you had arms like Cheewbacca or Sal in the Sharpmaker vid, my Military would remove a HUGE amount of hair. Another point is how are we shaving? I hold the knife at about a 15 degree angle and push it lightly along the skin, do some of you scrape the skin, holding the edge down?Pulling the blade up and down? No one has ever thought of this...
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
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Certified steel snob!
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- Jun 6, 2000
- Messages
- 3,625
Jeff, when I say Ultra Fine, I refer to the UF Benchstone by Spyderco it is a LOT smoother than step 4 a LOT smoother.
If I were to give a straight answer as the best utility edge for the Military, my choice would still be for the step 4 at 20 per side, but as I said I will try the step 3 at 20 next.
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
If I were to give a straight answer as the best utility edge for the Military, my choice would still be for the step 4 at 20 per side, but as I said I will try the step 3 at 20 next.
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
- Joined
- Oct 26, 2000
- Messages
- 6,104
Ok, I discussed this with someone who has a little knowledge on the subject, today (though we were talking 420V). As I said above, I get good edges on 420V, but it usually takes a couple of tries to get everything perfectly even.
Now, I think I know why. All it took was him saying "remember, we're talking about hard carbides in a relatively soft matrix", and it hit me.
I've been going with a thinner edge (30 degrees included) which cuts like crazy. But the knife in question sees regular heavy use.
My take on it is this:
The soft matrix is deforming while the carbides are not. I think that the reason I haven't been getting an even edge right off the bat, is that I'm touching up an edge that is no longer even to begin with, and being that it's not properly aligned, it's taking longer to sharpen.
The knife was ready for a touch-up, so instead of going straight to the Sharpmaker with it, I used a steel, trying to approximate the desired edge angle.
I then went to the Sharpmaker, and used the 40 degree included setting (I'm going to try the edge a little thicker, to see if it resists deformation better).
So the edge is a little steeper, but I didn't go to the fine stones and strop as usual, but left it a little rough-hopefully this will render better slicing performance. The edge still shaves, but this time it took one try and only a couple of minutes to get an even edge.
I think the steeling before sharpening made a significant difference, but I usually only think to do it on damaged or rolled edges.
Looks like I have a new habit.
There's my theory. I will see how the edge holds up compared to the thinner, polished edge (which has been phenomenal, IMO, on softer materials-unfortunately, I don't just cut softer materials) that I've been using over the next few weeks.
Now, I think I know why. All it took was him saying "remember, we're talking about hard carbides in a relatively soft matrix", and it hit me.
I've been going with a thinner edge (30 degrees included) which cuts like crazy. But the knife in question sees regular heavy use.
My take on it is this:
The soft matrix is deforming while the carbides are not. I think that the reason I haven't been getting an even edge right off the bat, is that I'm touching up an edge that is no longer even to begin with, and being that it's not properly aligned, it's taking longer to sharpen.
The knife was ready for a touch-up, so instead of going straight to the Sharpmaker with it, I used a steel, trying to approximate the desired edge angle.
I then went to the Sharpmaker, and used the 40 degree included setting (I'm going to try the edge a little thicker, to see if it resists deformation better).
So the edge is a little steeper, but I didn't go to the fine stones and strop as usual, but left it a little rough-hopefully this will render better slicing performance. The edge still shaves, but this time it took one try and only a couple of minutes to get an even edge.
I think the steeling before sharpening made a significant difference, but I usually only think to do it on damaged or rolled edges.
Looks like I have a new habit.
There's my theory. I will see how the edge holds up compared to the thinner, polished edge (which has been phenomenal, IMO, on softer materials-unfortunately, I don't just cut softer materials) that I've been using over the next few weeks.
Hmmmmmmmmmmmmm.
General, "step 3" on the Sharpmaker at 20 degrees per side is what I've got my Military sharpened at right now, and it doesn't "feel" that sharp, doesn't shave very well (thick arm hair) but cuts (slices) like a banshee on most anything I try. I guess I should quit worrying about whether it's sharp and just enjoy using it.
However, the difficulty I've experienced in getting a good, shaving sharp edge with this knife has caused frustration for me as it's one of the ways that I know I'm finished a given sharpening session. I wonder if this steel just needs a different "sharpness" test designed for it?
In any case, after reading Cliff's writings I'm going to try this knife at 15 degrees per side with various levels of polish and see how it works. I should have some findings tomorrow.
Jeff/1911.
General, "step 3" on the Sharpmaker at 20 degrees per side is what I've got my Military sharpened at right now, and it doesn't "feel" that sharp, doesn't shave very well (thick arm hair) but cuts (slices) like a banshee on most anything I try. I guess I should quit worrying about whether it's sharp and just enjoy using it.
However, the difficulty I've experienced in getting a good, shaving sharp edge with this knife has caused frustration for me as it's one of the ways that I know I'm finished a given sharpening session. I wonder if this steel just needs a different "sharpness" test designed for it?
In any case, after reading Cliff's writings I'm going to try this knife at 15 degrees per side with various levels of polish and see how it works. I should have some findings tomorrow.
Jeff/1911.
- Joined
- Apr 3, 2001
- Messages
- 485
i don't understand, i hear people talk about hard carbides in a soft steel matrix. but i also hear people say that the "steel" is fine grained. How big are the vandium carbides involved, and are they large enough to be sort of sticking out the sides of a thin edge? Thanks, Pete
Fellows,
I reprofiled my Military to 15 degrees per side, using the 30 degree "back bevel" slots in my Sharpmaker model 204. I then polished the edge to the finest level or step 4 (the "flats" of the white stone), and it was clearly very sharp. It still didn't shave hair terribly well however. It slices like crazy, and push cuts soft media very well, too.
Then, I stepped back to "step 3" (corners of the white stone) w/ SM 204 and it feels sharper, cuts possibly better and shaves about the same...not aggressively, but if you push hard enough it will remove arm hair. This is in stark contrast to the AUS-8 on my Calypso Jr. or CRKT M-16 both of which turn into veritable straight razors in no time with the sharpmaker at 40 degrees!
Anyway, this steel cuts very well. I will just no longer try to test it by shaving arm hair.
I'll write back once I have some idea about edge durability of my 30 degree grind w/ the Military's CPM440-V blade.
Jeff/1911.
I reprofiled my Military to 15 degrees per side, using the 30 degree "back bevel" slots in my Sharpmaker model 204. I then polished the edge to the finest level or step 4 (the "flats" of the white stone), and it was clearly very sharp. It still didn't shave hair terribly well however. It slices like crazy, and push cuts soft media very well, too.
Then, I stepped back to "step 3" (corners of the white stone) w/ SM 204 and it feels sharper, cuts possibly better and shaves about the same...not aggressively, but if you push hard enough it will remove arm hair. This is in stark contrast to the AUS-8 on my Calypso Jr. or CRKT M-16 both of which turn into veritable straight razors in no time with the sharpmaker at 40 degrees!
Anyway, this steel cuts very well. I will just no longer try to test it by shaving arm hair.
I'll write back once I have some idea about edge durability of my 30 degree grind w/ the Military's CPM440-V blade.
Jeff/1911.
- Joined
- Jun 6, 2000
- Messages
- 3,625
This ones about to get even more wierd...
I was so frustrated by the performance I had encountered, that I decided to try some stuff out.
I took my Military (15 per side polished edge on Ultra Fine Spyderco Benchstone) and used the Red (fine) duo folder DMT stone (blue on one side which is course and red on the other). I placed the red side on my 20 degree angle sharpmaker stick and gave it about 12 strokes on each side. The edge was most definatly not very shaving sharp at this point, it would but only with a lot of passes and effort. I then used the white stones to step three about 10 passes. The edge 'felt' exactly like it did before I started this, sharper than after the DMT stone, but hardly a super shaver. I then went on to do the step four at 20 degree's. Now one side shaved very well and the other did not. This told me that the edge was no longer perfectly symetrical. It was more likely a burr that was doing the cutting. I tested shaving and sharpening until I could not see a burr and the shaving was equal on both sides. The edge is now at step four at 20 per side. Guess what? it is now nearly hair popping sharp it shaves very very well with little effort
. I had run out of arm hair to test in getting the edge symetrical, so I went to chest hair... Very little of that left now either...
This makes me think two things.
1. The edge was not symetrical the first time round, but if this was the case it aught to have shaved VERY well on one side and poorly the other. This is what happens when I get the edge about right and then sharpen one side only about 7 times, one side becomes super razor sharp and the other won't shave worth a damn. This is the 'wire edge' doing the cutting then? Well I have got rid of the 'wire edge' and it shaves well on both sides now. The last time I played with the UF stone I did this test as well. I find that the shaving of hair is the only reliable test to make sure the edge is 100% symetrical.
I hold the blade and cut DOWN the arm/chest etc. If the edge shaves very well down my chest and not up it tells me that the blade (you are looking at the SPINE at this point as it cuts DOWN your arm/leg/chest. On the Spyderco Military this is the clip side with NO MARKINGS on the blade. If this side cuts better, then the edge is biased DOWN. Let me try to visualise this some way...
-Tip
-
- -
- -
- - Clipside edge
This is what you WANT TO HAVE
A perfect Pyramid profile.
Well if it is slicing well on the clip side edge then the profile in exageration is doing this...
- Tip
-
- -
- -
- - Clip side edge
So to get the edge symetrical, you have to remove some steel from the clip side edge to bring it back to the middle. If you sharpen the clip side edge too far, what you do is make the non clip side or FRONT MARKED blade come into favour like this.
-
-
- -
- -
- - Clip side edge.
-
- -
- - ------------------
- - - Thus by removing
- - Material from
this side, the
edge now favours
The UPCUT when
You shave.
Simply remove material from the FRONT or MARKED blade of the MILIARY TO BRING THE EDGE BACK TO A SYMETRICAL EDGE LIKE THIS.
-Tip
-
- -
- -
- -
Easy peasy!
All I can think is that the DMT stone removed enough fresh steel to let me get a good shaving edge.
I tried the same thing on my Starmate and got the same result a very good shaving edge on the step 4 of the Sharpmaker at 20 degree's.
The DMT stone seemed to make all the difference.
I would still like to add that the same edge on my 154CM LCC D/A sharpened EXACTLY the same way, including the DMT stone is a LOT sharper. I am talking literaly hair popping sharp, but it does not cut as aggressivly on other stuff like paper or wood.
Hope this weirdness helps in some way, sorry for the long long post.
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
[This message has been edited by The General (edited 06-21-2001).]
I was so frustrated by the performance I had encountered, that I decided to try some stuff out.
I took my Military (15 per side polished edge on Ultra Fine Spyderco Benchstone) and used the Red (fine) duo folder DMT stone (blue on one side which is course and red on the other). I placed the red side on my 20 degree angle sharpmaker stick and gave it about 12 strokes on each side. The edge was most definatly not very shaving sharp at this point, it would but only with a lot of passes and effort. I then used the white stones to step three about 10 passes. The edge 'felt' exactly like it did before I started this, sharper than after the DMT stone, but hardly a super shaver. I then went on to do the step four at 20 degree's. Now one side shaved very well and the other did not. This told me that the edge was no longer perfectly symetrical. It was more likely a burr that was doing the cutting. I tested shaving and sharpening until I could not see a burr and the shaving was equal on both sides. The edge is now at step four at 20 per side. Guess what? it is now nearly hair popping sharp it shaves very very well with little effort
This makes me think two things.
1. The edge was not symetrical the first time round, but if this was the case it aught to have shaved VERY well on one side and poorly the other. This is what happens when I get the edge about right and then sharpen one side only about 7 times, one side becomes super razor sharp and the other won't shave worth a damn. This is the 'wire edge' doing the cutting then? Well I have got rid of the 'wire edge' and it shaves well on both sides now. The last time I played with the UF stone I did this test as well. I find that the shaving of hair is the only reliable test to make sure the edge is 100% symetrical.
I hold the blade and cut DOWN the arm/chest etc. If the edge shaves very well down my chest and not up it tells me that the blade (you are looking at the SPINE at this point as it cuts DOWN your arm/leg/chest. On the Spyderco Military this is the clip side with NO MARKINGS on the blade. If this side cuts better, then the edge is biased DOWN. Let me try to visualise this some way...
-Tip
-
- -
- -
- - Clipside edge
This is what you WANT TO HAVE
A perfect Pyramid profile.
Well if it is slicing well on the clip side edge then the profile in exageration is doing this...
- Tip
-
- -
- -
- - Clip side edge
So to get the edge symetrical, you have to remove some steel from the clip side edge to bring it back to the middle. If you sharpen the clip side edge too far, what you do is make the non clip side or FRONT MARKED blade come into favour like this.
-
-
- -
- -
- - Clip side edge.
-
- -
- - ------------------
- - - Thus by removing
- - Material from
this side, the
edge now favours
The UPCUT when
You shave.
Simply remove material from the FRONT or MARKED blade of the MILIARY TO BRING THE EDGE BACK TO A SYMETRICAL EDGE LIKE THIS.
-Tip
-
- -
- -
- -
Easy peasy!
All I can think is that the DMT stone removed enough fresh steel to let me get a good shaving edge.
I tried the same thing on my Starmate and got the same result a very good shaving edge on the step 4 of the Sharpmaker at 20 degree's.
The DMT stone seemed to make all the difference.
I would still like to add that the same edge on my 154CM LCC D/A sharpened EXACTLY the same way, including the DMT stone is a LOT sharper. I am talking literaly hair popping sharp, but it does not cut as aggressivly on other stuff like paper or wood.
Hope this weirdness helps in some way, sorry for the long long post.
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
[This message has been edited by The General (edited 06-21-2001).]
- Joined
- Jun 6, 2000
- Messages
- 3,625
Awww its not come out well, I will try using letters instead
a
a a
a a
a a This is a good symetrical edge.
a -This bit you want to
a cut away!
a a
a a
a a
a a This is a clip side bias. To fix this, sharpen the clip side so the material is removed an the blade can become like the pyramid above. Even and equal.
a
a
a a
a a
a a
a a This is a FACE side bias. To get rid of this, sharpen the FACE side.
Hope this comes out...
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
a
a a
a a
a a This is a good symetrical edge.
a -This bit you want to
a cut away!
a a
a a
a a
a a This is a clip side bias. To fix this, sharpen the clip side so the material is removed an the blade can become like the pyramid above. Even and equal.
a
a
a a
a a
a a
a a This is a FACE side bias. To get rid of this, sharpen the FACE side.
Hope this comes out...
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
- Joined
- Jun 6, 2000
- Messages
- 3,625
No it did not work... Bugger.
Can anyone who understood that put up a picture using photopoint to explain what I have just said? Anyone understand any of it?
When the edge is sharpened too much on one side...
Put your two hands together right now. Make sure they are the same length. Ok?
Now imagine the right hand as you look at them is the clip side edge of the Military (if your finger tips are the edge of the knife and where your wrists are is the spine of the edge). Got that?
Well imagine you are sharpening the Clip Side of the edge, this is your right hand, yes? What happens? Well you are removing steel from that side yes? Well simulate that and drop that hand an inch or so. What happens? The left hand (Front side of Military edge) is now taller and thus is now the sharper side and the side that will cut better. This side will in fact, bend over slightly towards the right hand. So bend your left hand slightly towards the right hand. This is NOT a WIRE EDGE as I understand it, but rather an edge that is NOT symetrical, thus it cuts very well on one side, but not very well on the other. Not a good thing. It is also a weaker edge.
How would you fix this?
Well you want to make your left hand shorter so it is the same length of you right jand, yes?
Look at your hands now. The left hand is still an inch longer than the right, so to make them the same, you sharpen the left hand (Face side of blade) and the left hand will drop to the same length of the right hand. Once both are the same length, you have the pyramid effect.
The best way to make sure both are 'symetrical' is to see if it shaves as well up as well as down your arm. In other words make sure both sides of the edge shave as well. Once you get this right, you are in possesion of a symetrical edge.
God, I hope some of that makes sense.
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
Can anyone who understood that put up a picture using photopoint to explain what I have just said? Anyone understand any of it?
When the edge is sharpened too much on one side...
Put your two hands together right now. Make sure they are the same length. Ok?
Now imagine the right hand as you look at them is the clip side edge of the Military (if your finger tips are the edge of the knife and where your wrists are is the spine of the edge). Got that?
Well imagine you are sharpening the Clip Side of the edge, this is your right hand, yes? What happens? Well you are removing steel from that side yes? Well simulate that and drop that hand an inch or so. What happens? The left hand (Front side of Military edge) is now taller and thus is now the sharper side and the side that will cut better. This side will in fact, bend over slightly towards the right hand. So bend your left hand slightly towards the right hand. This is NOT a WIRE EDGE as I understand it, but rather an edge that is NOT symetrical, thus it cuts very well on one side, but not very well on the other. Not a good thing. It is also a weaker edge.
How would you fix this?
Well you want to make your left hand shorter so it is the same length of you right jand, yes?
Look at your hands now. The left hand is still an inch longer than the right, so to make them the same, you sharpen the left hand (Face side of blade) and the left hand will drop to the same length of the right hand. Once both are the same length, you have the pyramid effect.
The best way to make sure both are 'symetrical' is to see if it shaves as well up as well as down your arm. In other words make sure both sides of the edge shave as well. Once you get this right, you are in possesion of a symetrical edge.
God, I hope some of that makes sense.
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
General,
Makes perfect sense to me. I admire your considerable effort in explaining this.
I tried my 30 degree sharpened Military on vegetables tonight, as I prepared a salad for dinner. When cutting tomatoes or cucumbers, the 30 degree angle slices MUCH better than did the previous 40 degree profile!
Cliff, You weren't kidding. It's really quite noticible what a difference this has made, at least on soft media with this knife.
Jeff/1911.
Makes perfect sense to me. I admire your considerable effort in explaining this.
I tried my 30 degree sharpened Military on vegetables tonight, as I prepared a salad for dinner. When cutting tomatoes or cucumbers, the 30 degree angle slices MUCH better than did the previous 40 degree profile!
Cliff, You weren't kidding. It's really quite noticible what a difference this has made, at least on soft media with this knife.
Jeff/1911.
Cliff Stamp
BANNED
- Joined
- Oct 5, 1998
- Messages
- 17,562
OwenM:
Note all steels are like this, the alloy carbides are much harder than the steel they are embedded in. The edge deforms around them.
Pj, carbides are very small, the size depends both on the element in the carbide and the level of segregation in the steel. They do stick out of the surface and thus give the alloy steels their tremendous wear resistance, just like the teeth of a saw take wear when cutting and you can extend its lifetime by impulse hardening the teeth without changing the main body of the saw (which is similar to using harder carbides in the same steel matrix of a blade).
Wayne :
A wire edge is generally what happens when the burr you are describing is aligned perpendicular to the spine. You will see high performance until it deforms which is very quickly. They way to get rid of it is to increase the angle just a little, a degree or so, and alternate sides using light pressure on an abrasive that can grind it off. The other method is to use a stropping motion as since it exerts little pressure on the edge, the burr won't get the necessary force to deform and will be ground away. Joe describes both of these methods in the FAQ.
One of the reasons the Sharpmaker forms burrs so readily is that you are honing with a tremendous pressure on the edge. Even though the force you are applying is probably light, say 100 - 200 g, due to the very small contact areas on the corners, the pressure is probably around 500 lbs per sq in.
On top of that which is what makes the situation even worse, the abrasive is probably not aggressive enough to cut into the steel before it deforms (in regards to high Vanadium steels) . To minimize this make sure you are drawing the blade along the hone, using light pressure and avoid the corners. While they will speed up metal removal, unless the steel is very easy to work (like 1095) they are going to be deforming it readily.
The most important step in getting rid of a burr is not to have it on the edge in the first place. Switch sides often to minimize its formation. Use light force and large contact areas to reduce the pressure on the edge. Clean your hones often as loaded hones have a very low abrasion factor. And make sure you use hones than can aggressivly cut the steel you are sharpening.
Jeff, the next step is to go lower still. For that you would probably want a smaller knife though as the Military was designed for decently heavy work. For most dedicated cutting work you can be around 8 degrees or so per side, with a decent steel, and see no problems. The only reason that most production knives come so thick is that people do a lot of really heavy non-cutting work with them. A lot of the high end performance custom knives have much thinner edges as they are made for people who just want to cut with a knife.
The next step up in performance is to optomize the main bevel. For a high performance cutting knife the blade should not be any thicker than 0.01" behind the edge. Once you start going lower than that the performance truely starts getting fantastic. These are not edges that you would chop, twist, scrap or pry with, but for light materials they will cut very well.
With an optomized edge and primary grind the level of performance will be that high that the blade will outcut even those 1/32" replaceable utility knives (the edges on them are too thick, and the handle ergonomics also make for poor cutting ability). If you really want to impress a tradesman loan him one of your knives that will out perform the knives they carry, as they will cut circles around the "tactical" knives. Boyes knives can do this, as well as Phil Wilson, Ed Schott, I have also used blades from Ray Kirk and Ed Caffery that would do this easily as well.
Here is a blade that has the complete package, it is a MEUK by Allen Blade. Allen did an excellent job on the sheath and grip as well as the shape of the blade. It has a high quality steel (52100) and heat treat (Ed Caffery) , plus an excellent edge geometry combined with a matching primary grind (Ed Caffery) :
http://www.physics.mun.ca/~sstamp/images/meuk_side.jpg
http://www.physics.mun.ca/~sstamp/images/meuk_top.jpg
The primary grind is fully convex with a light distal taper, and narrows to an edge which is barely visible, there is just a *hint* of a secondary grind. The blade is only 0.005" thick behind the edge bevel which is ground at about 11 +/- 1 degrees per side (difficult to measure as it is so small). It melts through most materials like they are not even there :
http://www.physics.mun.ca/~sstamp/images/meuk_wood_cut.jpg
I used the modified Sub-Sniper from Lynn Griffith for comparsion. And while the modified MEUK could slice through the wood more than half way with each cut, the Sub-Sniper which I have heavy thinned (9.5 degree edge bevel) could not even cut halfway on a stroke. The primary grind is significantly thicker and is has a higher drag profile due to the flat vs convex grind.
The above is repeatable, I did it a half a dozen times with each blade. I have done lots more cutting with it for the past while and overall it is performing very well.
-Cliff
[This message has been edited by Cliff Stamp (edited 06-22-2001).]
Note all steels are like this, the alloy carbides are much harder than the steel they are embedded in. The edge deforms around them.
Pj, carbides are very small, the size depends both on the element in the carbide and the level of segregation in the steel. They do stick out of the surface and thus give the alloy steels their tremendous wear resistance, just like the teeth of a saw take wear when cutting and you can extend its lifetime by impulse hardening the teeth without changing the main body of the saw (which is similar to using harder carbides in the same steel matrix of a blade).
Wayne :
A wire edge is generally what happens when the burr you are describing is aligned perpendicular to the spine. You will see high performance until it deforms which is very quickly. They way to get rid of it is to increase the angle just a little, a degree or so, and alternate sides using light pressure on an abrasive that can grind it off. The other method is to use a stropping motion as since it exerts little pressure on the edge, the burr won't get the necessary force to deform and will be ground away. Joe describes both of these methods in the FAQ.
One of the reasons the Sharpmaker forms burrs so readily is that you are honing with a tremendous pressure on the edge. Even though the force you are applying is probably light, say 100 - 200 g, due to the very small contact areas on the corners, the pressure is probably around 500 lbs per sq in.
On top of that which is what makes the situation even worse, the abrasive is probably not aggressive enough to cut into the steel before it deforms (in regards to high Vanadium steels) . To minimize this make sure you are drawing the blade along the hone, using light pressure and avoid the corners. While they will speed up metal removal, unless the steel is very easy to work (like 1095) they are going to be deforming it readily.
The most important step in getting rid of a burr is not to have it on the edge in the first place. Switch sides often to minimize its formation. Use light force and large contact areas to reduce the pressure on the edge. Clean your hones often as loaded hones have a very low abrasion factor. And make sure you use hones than can aggressivly cut the steel you are sharpening.
Jeff, the next step is to go lower still. For that you would probably want a smaller knife though as the Military was designed for decently heavy work. For most dedicated cutting work you can be around 8 degrees or so per side, with a decent steel, and see no problems. The only reason that most production knives come so thick is that people do a lot of really heavy non-cutting work with them. A lot of the high end performance custom knives have much thinner edges as they are made for people who just want to cut with a knife.
The next step up in performance is to optomize the main bevel. For a high performance cutting knife the blade should not be any thicker than 0.01" behind the edge. Once you start going lower than that the performance truely starts getting fantastic. These are not edges that you would chop, twist, scrap or pry with, but for light materials they will cut very well.
With an optomized edge and primary grind the level of performance will be that high that the blade will outcut even those 1/32" replaceable utility knives (the edges on them are too thick, and the handle ergonomics also make for poor cutting ability). If you really want to impress a tradesman loan him one of your knives that will out perform the knives they carry, as they will cut circles around the "tactical" knives. Boyes knives can do this, as well as Phil Wilson, Ed Schott, I have also used blades from Ray Kirk and Ed Caffery that would do this easily as well.
Here is a blade that has the complete package, it is a MEUK by Allen Blade. Allen did an excellent job on the sheath and grip as well as the shape of the blade. It has a high quality steel (52100) and heat treat (Ed Caffery) , plus an excellent edge geometry combined with a matching primary grind (Ed Caffery) :
http://www.physics.mun.ca/~sstamp/images/meuk_side.jpg
http://www.physics.mun.ca/~sstamp/images/meuk_top.jpg
The primary grind is fully convex with a light distal taper, and narrows to an edge which is barely visible, there is just a *hint* of a secondary grind. The blade is only 0.005" thick behind the edge bevel which is ground at about 11 +/- 1 degrees per side (difficult to measure as it is so small). It melts through most materials like they are not even there :
http://www.physics.mun.ca/~sstamp/images/meuk_wood_cut.jpg
I used the modified Sub-Sniper from Lynn Griffith for comparsion. And while the modified MEUK could slice through the wood more than half way with each cut, the Sub-Sniper which I have heavy thinned (9.5 degree edge bevel) could not even cut halfway on a stroke. The primary grind is significantly thicker and is has a higher drag profile due to the flat vs convex grind.
The above is repeatable, I did it a half a dozen times with each blade. I have done lots more cutting with it for the past while and overall it is performing very well.
-Cliff
[This message has been edited by Cliff Stamp (edited 06-22-2001).]
Cliff,
I will next be doing some work with my Spyderco large Calypso in VG-10. I thought that I had already reprofiled it to 15+15 degrees (from 20+20)...
But now, after yesterday's experience with reprofiling the Military I realize that I probably only had succeeded in adding a nice 30 degree back bevel behind the existing 40 degree edge. I'll use marker on the edge like I did with the Military this time, so that I can see when I've finished sharpening and the two sides have "met".
Thank you for the general advice about use of the Sharpmaker, particularly regarding optimal pressure to apply as I think I've probably been pressing too hard while sharpening. This might explain some inconsistent results I've noted in the past.
Jeff/1911.
I will next be doing some work with my Spyderco large Calypso in VG-10. I thought that I had already reprofiled it to 15+15 degrees (from 20+20)...
But now, after yesterday's experience with reprofiling the Military I realize that I probably only had succeeded in adding a nice 30 degree back bevel behind the existing 40 degree edge. I'll use marker on the edge like I did with the Military this time, so that I can see when I've finished sharpening and the two sides have "met".
Thank you for the general advice about use of the Sharpmaker, particularly regarding optimal pressure to apply as I think I've probably been pressing too hard while sharpening. This might explain some inconsistent results I've noted in the past.
Jeff/1911.
- Joined
- Mar 21, 2001
- Messages
- 53
Thank you all, I was beginning to think I was a complete moron when it comes to knife sharpening. I got my Native a couple of weeks ago. It came with a shaving sharp factory edge wich disappeared before the day was out. All I cut was some cardboard, some wood , paper and a lot of arm hair! (I guess it must have been a burr on the edge)since then I've been trying to get the edge back on the sharpmaker but no such luck. Had almost given up when I saw this post.
Again thanks, now all thats left is to try very gently to get this edge back.
------------------
Words only go so far.
Experience is the true teacher.
Again thanks, now all thats left is to try very gently to get this edge back.
------------------
Words only go so far.
Experience is the true teacher.
Being in the habit of re-profiling every knife I buy, I had similar difficulty with my Spyderco Military in 440V.
The most difficulty seemed to be establishing a back bevel of something less than 15 degrees. It took a long time to remove enough metal to achieve a wire edge.
From that point on, I remove the wire edge with Sharpmaker 204 at 15 degrees per side, polished briefly with leather hone with 600-grit powder and finished with 10000-grit abrasive powder on leather hone.
The final edge is very sharp. It moves through newsprint with barely a hiss. It slices like a demon and seems to hold up well for whittling and general cutting.
The difficult part was the re-profiling. The experience was somewhat like trying to hone rubber. Once past that stage, it was like sharpening ATS34.
The most difficulty seemed to be establishing a back bevel of something less than 15 degrees. It took a long time to remove enough metal to achieve a wire edge.
From that point on, I remove the wire edge with Sharpmaker 204 at 15 degrees per side, polished briefly with leather hone with 600-grit powder and finished with 10000-grit abrasive powder on leather hone.
The final edge is very sharp. It moves through newsprint with barely a hiss. It slices like a demon and seems to hold up well for whittling and general cutting.
The difficult part was the re-profiling. The experience was somewhat like trying to hone rubber. Once past that stage, it was like sharpening ATS34.
- Joined
- Mar 21, 2001
- Messages
- 53
Ok I've almost got a good shaving edge on both sides of the blade now. My question now is do you sharpen the side that shaves better, ex : the knife shaves better when clip is in towards arm. Is that the side you then sharpen ? I just have some problems doing the final adjustements . thanks
------------------
Words only go so far.
Experience is the true teacher.
- Joined
- Jun 6, 2000
- Messages
- 3,625
I will try and be a little clearer, bear with me!
When you say the side that shaves the best, it can get a little confusing after all you might consider the shaveing side as being the blade 'face' that is nearest your skin or the blade 'face' that you are looking at as you shave.
So, when you take a 'normal' knife, they tend to have a side that does not have a clip on it and has writing etc on the knifeblade. Look at the pic of the EDC in the banner up at the top! That is the 'front or NON-clip side'
If you are right handed and you hold that knife in the normal way, when you shave DOWN, this 'front' face is next to your skin.
When you shave UP the arm, the 'back or clip face' is next to the skin. Does that make sense?
Going with this description, if the 'front' side (shaving DOWN your arm) is better than the 'back' face, then you need to sharpen the OTHER side of the blade. So if the 'front' face shaves better, sharpen the 'back' face once and shave a little more, then do one more and test again and again until the back face shaves a little better now. At this point one low pressure pass on the 'front' side will make them equal. Wheeew!
In summery.
1. If shave down is good but shave up is bad sharpen the clip side.
2. If the shave UP is good, but the shave down is not so good, sharpen the front side.
Does this help at all?
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
'in Spyderco I trust'
When you say the side that shaves the best, it can get a little confusing after all you might consider the shaveing side as being the blade 'face' that is nearest your skin or the blade 'face' that you are looking at as you shave.
So, when you take a 'normal' knife, they tend to have a side that does not have a clip on it and has writing etc on the knifeblade. Look at the pic of the EDC in the banner up at the top! That is the 'front or NON-clip side'
If you are right handed and you hold that knife in the normal way, when you shave DOWN, this 'front' face is next to your skin.
When you shave UP the arm, the 'back or clip face' is next to the skin. Does that make sense?
Going with this description, if the 'front' side (shaving DOWN your arm) is better than the 'back' face, then you need to sharpen the OTHER side of the blade. So if the 'front' face shaves better, sharpen the 'back' face once and shave a little more, then do one more and test again and again until the back face shaves a little better now. At this point one low pressure pass on the 'front' side will make them equal. Wheeew!
In summery.
1. If shave down is good but shave up is bad sharpen the clip side.
2. If the shave UP is good, but the shave down is not so good, sharpen the front side.
Does this help at all?
------------------
Wayne.
"To strive to seek to find and not to yield"
Tennyson
Ranger motto
A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
'in Spyderco I trust'
- Joined
- Mar 21, 2001
- Messages
- 53
Hi GENERAL thanks for the clarification. I'll get on it later today and tell you how it went. This post is excellent. As I said I was starting to give up hope of ever getting the native sharp again. Maybe you should write a special "sharpening super (difficult) steels " thing and send it in as an addition to the excellent sharpening faq.
just a tought.
------------------
Words only go so far.
Experience is the true teacher.
just a tought.
------------------
Words only go so far.
Experience is the true teacher.
