I might have come to the end of my super steel lust

[Jet B]

Yep, exactly.

I don't have a burr once I finish sharpening, my SIC stones cut very clean, I strop just to put the finial touch on the edge, that is what I call the burr, but it's not really a burr.

Roger. I think I got you guys.

When I form my micro bevel at 600 grit, I will keep the passes light and maybe do them "edge into" with the WEPS paddles. I will just strop lightly to finish the edge. I'm excited to see how this performs, I bet it will be a tomato cutting demon with this aggressive edge.

[Zenith]

Dont forget to let us know how the edge performs.

[Cliff Stamp]

I don't have a burr once I finish sharpening, my SIC stones cut very clean, I strop just to put the finial touch on the edge, that is what I call the burr, but it's not really a burr.

I normally clean an edge on plain leather, canvas or newsprint just to get the water off the edge as I often don't use stainless and to also oil/wax the edge. It is very little, just maybe 1-2 passes per side, ultra light, 5-10 grams, similar force as used on the final honing.

[Evil D]

Once again you guys (and this is the 2nd time for you Cliff) have made me rethink my sharpening technique. I love this forum

[jackknifeh]

There is a balance or should I say optimal edge finish that maximizes both cutting efficiency (Slicing) and edge retention and from my own testing that seems to be in the 12-14 Micron range.

It's not just the high carbide volume steels either that benefit from a coarser edge, that's semi polished.

The more efficient the knife cuts the less force needed to make that cut, more force is never a good thing, that's in a draw cut.

The problem with the low alloy steels is that they really don't have the carbide volume to support that cutting edge when it's polished so what happens is it just goes blunt and it's done. Believe me people wouldn't believe how fast the lower alloy steels go dull on abrasive materials like rope or cardboard with polished edges. Now using a coarser edge increases cutting efficiency so that will help letting the edge cut longer before going dead.

Now I know this isn't what some want to hear, but that's really how it works.

With the high carbide steels this is even more effective because the carbides just take over earlier on.

I have seen the measured difference in edge retention of 50% or more depending on the steel.

If I understand you correctly:
1. Steels like AUS-8 with an edge sharpened with a 320 grit EP stone should last longer than if you polished it through the 1000 grit stone and then strop. Is this right?

2. The better steels like S30V and M4 will hold up better than AUS-8 when sharpened with the higher grit stones, strops, etc. because they have the carbides to support a more refined, polished edge. But, if you sharpened S30V and stop after the EP 320 grit stone, the edge retention would be even longer on that knife than if you progressed to the higher grits. Is this right?

3. When I have S30V that has gotten just a little dull I have been touching it up with a Spyderco UF ceramic stone. Maybe the better stone to use would be the fine or even the medium grit stones. Is this right?

Summary: When does a super polished edge last longer than a coarser or toothier edge? Does it ever? I'm thinking about edge retention, not necessarily the hair popping edge you have right after sharpening.

I appreciate the effort you take to determine your own opinion on these subjects. I would trust your thoughts because it seems you have done enough research to get technical info on steel, then put it to work in real world situations. Then you have the generosity to share the results. That in itself takes considerable time. Thank you.

Jack

[Ankerson]

If I understand you correctly:
1. Steels like AUS-8 with an edge sharpened with a 320 grit EP stone should last longer than if you polished it through the 1000 grit stone and then strop. Is this right?

2. The better steels like S30V and M4 will hold up better than AUS-8 when sharpened with the higher grit stones, strops, etc. because they have the carbides to support a more refined, polished edge. But, if you sharpened S30V and stop after the EP 320 grit stone, the edge retention would be even longer on that knife than if you progressed to the higher grits. Is this right?

3. When I have S30V that has gotten just a little dull I have been touching it up with a Spyderco UF ceramic stone. Maybe the better stone to use would be the fine or even the medium grit stones. Is this right?

Summary: When does a super polished edge last longer than a coarser or toothier edge? Does it ever? I'm thinking about edge retention, not necessarily the hair popping edge you have right after sharpening.

I appreciate the effort you take to determine your own opinion on these subjects. I would trust your thoughts because it seems you have done enough research to get technical info on steel, then put it to work in real world situations. Then you have the generosity to share the results. That in itself takes considerable time. Thank you.

Jack

1. Yes

2. Yes

3. The Fine or the brown stones work great.

Summary:

They don't...


The optimal on the EP would be off the 600 grit stone.

[Evil D]

The optimal on the EP would be off the 600 grit stone.

I'll give it a shot and micro my 20CP off the 600 and let ya know how it works for me. Thanks a lot for all the advice everyone.

[Ankerson]

I'll give it a shot and micro my 20CP off the 600 and let ya know how it works for me. Thanks a lot for all the advice everyone.

I used the 600 grit most of the time until I got my Congress Moldmaster SIC Stones, now I leave it at the 400 grit Congress finish. (About the same)

I finish the edge off with a SIC loaded strop (Slurry from a Fine Norton SIC Stone)

[bchan]

On a very basic level, if you are slicing or draw cutting then the lower the grit finish the higher the cutting ability and edge retention. If you do push cutting it is the opposite. If you use the finish which is opposite the cutting method then the performance will be very low in both respects so ideally you use two different knives for both and keep them at the ideal finishes.

For most people you are doing a mix of the two and thus the optimal finish will be somewhere in between, this is why Joe Talmadge advocated in the late nineties to keep one section of the edge very coarse and use that for the slicing and keep the rest of the blade very fine for push cutting. Which part of the blade is which depends on cutting technique.

I am still trying to digest what you experts are saying. What I don't understand is why would a coarser finish is good for slicing, and a finer finish is good for push cutting. Can you explain a bit more? Thanks!

[Douglas]

You should listen to the experts and not me, but I believe the coarse finish gives you an edge with what are in effect microserrations. But serrations, micro or not, won't help with a push cut. For serrations to be effective you've got to have the edge moving relative to the cut.

[Evil D]

I am still trying to digest what you experts are saying. What I don't understand is why would a coarser finish is good for slicing, and a finer finish is good for push cutting. Can you explain a bit more? Thanks!

Well, my logic (simple as it may be) is that you see teeth on a saw for a reason. Try slicing a tomato with a polished edge vs. a course edge. Of course, this depends on what you're cutting if it makes as much difference.

[Cliff Stamp]

What I don't understand is why would a coarser finish is good for slicing, and a finer finish is good for push cutting.

I am not exactly sure how much detail you want, on a fundamental level it is about fracture mechanics and how cutting happens when the surface of a material has the rupture pressure exceeded and how a cut continues by the same process and usually is also influenced by gross fracture of the material (i.e. splitting).

To start, the simplest cut is a straight push, the edge comes in contact with a material, there is a pressure when the surface of the edge hits the surface of the material. As you keep pressing this pressure increases and is on both on the material and on the edge. At some point this pressure will be so high the material being cut will break apart like a balloon popping just on a very small scale.

(or the edge will if you try to cut something that has a high rupture pressure than the edge, i.e., try to cut a ceramic plate with the edge of a knife)


If you leave the edge with a very coarse finish, it initially sinks in very quickly as the tips of the teeth generate very high pressures, however on most materials the area of the teeth (all the ups/downs) smear out the force and generate a much lower pressure for a given force so you have to press harder.

The simplest way to see this on a macroscopic scale is to press a serrated Spyderco into a turnip and do it with a plain edge. The teeth of the serrated edge initially go in much easier but as they sink in it start to become difficult as there is much more length in all the curves and a straight edge of similar angle/thickness thus push cuts much easier as it generates a higher pressure at a given force (it also causes crack propagation easier as all the force is in the same line where as serrated blades jiggers the force all over the place due to the curvature of the serrations).

However, when you do a draw cut something very different happens. It starts the same as the points of the teeth sink in very rapidly as again the points make a very high pressure, but then because you draw it (slice) the material is broken inbetween the teeth and the teeth now sink again very easily into the material as the points again are the high pressure points, and again as you draw the blade you clear the material and stop the "smearing" effect.

If you make a very long draw you can make the cut happen almost at the point just requiring the tooth penetration alone which is very little. For example, and to be very specific, if you take a blade which can push cut 3/8" hemp with a high polish at say 10 lbs then if you leave it with a coarse edge you can make a draw with just 1-2 lbs as again all you are really pushing into the material on a slice is just the depth of the teeth.

[Slash]

I won't get into coarse vrs. fine edges. Most of us know the difference. I'll mainly focus on the chipping issue and high end thin edge steels. Cardboard is just plain nasty. What it does is push opposite directional force at the same time, in turn promotes chipping. Especially when you're dealing with high end edge retention type hard steels. They just don't have the same properties as steels that role under pressure. Maybe, I'm wrong in my assumption? I really don't know what else to say. All I know is what is tried and trued...carbon steels.

[Evil D]

I am not exactly sure how much detail you want, on a fundamental level it is about fracture mechanics and how cutting happens when the surface of a material has the rupture pressure exceeded and how a cut continues by the same process and usually is also influenced by gross fracture of the material (i.e. splitting).

To start, the simplest cut is a straight push, the edge comes in contact with a material, there is a pressure when the surface of the edge hits the surface of the material. As you keep pressing this pressure increases and is on both on the material and on the edge. At some point this pressure will be so high the material being cut will break apart like a balloon popping just on a very small scale.

(or the edge will if you try to cut something that has a high rupture pressure than the edge, i.e., try to cut a ceramic plate with the edge of a knife)


If you leave the edge with a very coarse finish, it initially sinks in very quickly as the tips of the teeth generate very high pressures, however on most materials the area of the teeth (all the ups/downs) smear out the force and generate a much lower pressure for a given force so you have to press harder.

The simplest way to see this on a macroscopic scale is to press a serrated Spyderco into a turnip and do it with a plain edge. The teeth of the serrated edge initially go in much easier but as they sink in it start to become difficult as there is much more length in all the curves and a straight edge of similar angle/thickness thus push cuts much easier as it generates a higher pressure at a given force (it also causes crack propagation easier as all the force is in the same line where as serrated blades jiggers the force all over the place due to the curvature of the serrations).

However, when you do a draw cut something very different happens. It starts the same as the points of the teeth sink in very rapidly as again the points make a very high pressure, but then because you draw it (slice) the material is broken inbetween the teeth and the teeth now sink again very easily into the material as the points again are the high pressure points, and again as you draw the blade you clear the material and stop the "smearing" effect.

If you make a very long draw you can make the cut happen almost at the point just requiring the tooth penetration alone which is very little. For example, and to be very specific, if you take a blade which can push cut 3/8" hemp with a high polish at say 10 lbs then if you leave it with a coarse edge you can make a draw with just 1-2 lbs as again all you are really pushing into the material on a slice is just the depth of the teeth.

Damn look at the big brain on Cliff! I love reading your posts man. Usually i have no idea what you're talking about and feel dumb but i absorbed most of that and it makes perfect sense, especially your example about the serrations into the turnip. The part about more edge being pushed through creating more resistance makes it very clear. I do tend to make almost exclusively draw/slice cuts so i'm definitely going to look into this toothy edge stuff.

[bchan]

Thanks Cliff for the very detailed and clear examples. I really appreciate your posts, I learn a lot from them.

[Cliff Stamp]

I do tend to make almost exclusively draw/slice cuts so i'm definitely going to look into this toothy edge stuff.

One thing you might want to do a little experimenting with is the angle of the blade on the hone because as the teeth get larger the angle they are set at (the rake) will be very obvious during the cutting. I always rake teeth back toward the handle this way when I push the point into something the teeth are back raked and they enter quite smoothly. If I then draw down and towards me the teeth are now front raked and they cut extremely aggressively. The teeth are raked at the angle of the scratches which are quite visible even with the teeth are not. The effect of this is very prominent at low grit finishes and you can make the cutting very different when you are drawing towards you or away if you want, or if you make the teeth have no rake they will be neutral basically and have the same lower aggression in either direction.

[Evil D]

One thing you might want to do a little experimenting with is the angle of the blade on the hone because as the teeth get larger the angle they are set at (the rake) will be very obvious during the cutting. I always rake teeth back toward the handle this way when I push the point into something the teeth are back raked and they enter quite smoothly. If I then draw down and towards me the teeth are now front raked and they cut extremely aggressively. The teeth are raked at the angle of the scratches which are quite visible even with the teeth are not. The effect of this is very prominent at low grit finishes and you can make the cutting very different when you are drawing towards you or away if you want, or if you make the teeth have no rake they will be neutral basically and have the same lower aggression in either direction.

That's real interesting, sort of like a backwards wood saw.

[jackknifeh]

I am still trying to digest what you experts are saying. What I don't understand is why would a coarser finish is good for slicing, and a finer finish is good for push cutting. Can you explain a bit more? Thanks!

I don't know if this is an explaination. But this is what I did a few minutes ago. I have a fine grit 5" Spyderco ceramic stone on a 5" EP stone blank. I touched up the edge of my Sage4 (S30V) with it. The edge angle is 19 and the back bevel is 14 per side. I looked at the edge with a 20x loupe before and after I used the fine stone. It is considerably toothier after the touch up. Then I started whittling on a stick about the size of a finger. I tried push cuts where the same spot on the blade cuts through a pretty thick slice of wood. Then I slice through the stick starting the cut at the tip and finishing up close to the heel. That slice gave me a lot less resistance getting the blade through the wood. It actually felt like the edge was sawing through the wood. This is the first time I've ever cut through the wood trying to notice any difference in how I was cutting. Then I took a Sage1 with approx. the same angles that still had about as smooth an edge as I can get. That knife push cut through the wood a lot easier than the toothier edge on the Sage4. Knowing this is cool because when I try to cut small limbs I'll know how to cut it depending on how I have sharpened the knife I'm using. This is just what I've noticed on tomatoes. The toothier edge will cut through the skin immediately when you slice. The smooth edge pushes in on the tomatoe a little as you slice before cutting through the skin. Also, I was surprised how toothy the 303F stone left the edge. Now I'm thinking of getting the 303M and putting it on an EP blank as well. SH**. More money. When will it end? BTW, after using the fine ceramic stone with the toothier edge it still sliced phone book paper like it was air almost.

Jack

[Evil D]

So today i made a point to cut a good amount of cardboard to test this micro bevel, and as expected the chipping issue is pretty much solved. At least, i couldn't see any chipping through my 10x loupe. Sharpness seems about the same, but of course it dulled to the point that it barely shaves hair. Of course, it still cuts cardboard and slices paper pretty effortlessly which is the most important thing for me...long term edge retention.

However, i think i've come to a conclusion about myself and my EDC needs/habits. Since i enjoy and obsess over sharpening pretty much on a daily basis, steels like this can be wasted on me since the point of a steel like this is to go the distance without being sharpened. For what i cut, it seems like S30V is a happy medium...it isn't difficult to sharpen (for me anyway) and it'll get me through a shift at work without dulling to the point that it cuts so poorly that it hinders my work. I still love my 20CP for those chance instances when sharpening is not an option. I really hope someday this steel becomes more common place and less expensive. I wouldn't mind giving M4 a shot, but it would have to come in a Para 2

[Jet B]

So today i made a point to cut a good amount of cardboard to test this micro bevel, and as expected the chipping issue is pretty much solved. At least, i couldn't see any chipping through my 10x loupe. Sharpness seems about the same, but of course it dulled to the point that it barely shaves hair. Of course, it still cuts cardboard and slices paper pretty effortlessly which is the most important thing for me...long term edge retention.

However, i think i've come to a conclusion about myself and my EDC needs/habits. Since i enjoy and obsess over sharpening pretty much on a daily basis, steels like this can be wasted on me since the point of a steel like this is to go the distance without being sharpened. For what i cut, it seems like S30V is a happy medium...it isn't difficult to sharpen (for me anyway) and it'll get me through a shift at work without dulling to the point that it cuts so poorly that it hinders my work. I still love my 20CP for those chance instances when sharpening is not an option. I really hope someday this steel becomes more common place and less expensive. I wouldn't mind giving M4 a shot, but it would have to come in a Para 2

Great to hear it helped with the chipping issues. I'd be curious to know if that thing would be hair shaving sharp again after some light passes on the micro bevel and a bit of stropping?