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Edge retention with different grit finishes on 3Cr13 stainless

Posted by CliffStamp 
Edge retention with different grit finishes on 3Cr13 stainless
October 25, 2014 05:23AM
Overview and summary : [www.cliffstamp.com]

Details on individual stones follow.

--

Dressing stone : [www.cliffstamp.com]

Summary :

Quote

Since it is extremely hard there is no real issue with many of the problems with waterstones and I could set the apex on the Everyday Essentials fairly trivially to :

-get a push cut on light exercise paper at about 1/4"
-shave (but rough)
-35-40% of optimal sharpness measured on the Bergia
-5 lbs cut on 1/2" help, 2" draw

I did a couple of edge retention runs, TCE of 3.6 (2) in with a 15 dps micro-bevel. This is actually slightly higher than the Farid/K2 with the as-boxed performance.


Apex will take a lot of damage when formed :



The very coarse edge does however wear in stages (points, then scallops, finally large flat regions) so the edge retention is still solid :



Spyderco thread : [www.spyderco.com]



Edited 2 time(s). Last edit at 01/17/2015 10:38AM by CliffStamp.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 25, 2014 05:31AM
Suehiro 'Chemical' 320 grit : [www.cliffstamp.com]

This is not an easy stone to set the apex, very nice to grind though. To set the apex, the basic procedure is :
Quote



-clean/lapp the surface
-rinse well
-let dry until a pass doesn't form a swarf
-carefully abrade the apex using all the burr minimization techniques to set the micro-bevel

Even then though, getting above 35% of optimal sharpness consistently isn't easy because this is both a very coarse stone and it release abrasive easily so those big pieces roll around and can roll right into the apex vs cutting it from underneath. To really get a high sharpness the apex has to be first set without damage and then the micro-bevel formed without damage. This requires in the shaping stage :

-either extremely light force or working a thick and refined mud

and in the micro-bevel :

-very light force, ideally on a lapped/evened surface

The edge is still very coarse, but much finer than what is produced off of the dressing stone :



The edge retention is higher, TCE 5.2 (1)
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 25, 2014 10:59AM
Naniwa Aotoshi 2000 : [www.cliffstamp.com]

This is a stark contrast from the two very coarse stones in almost all aspects. The first thing is that the edge retention slicing the hemp is a lot lower :



This isn't surprising and is consistent with past results, however there are a number of other differences, a critical one is that it cuts completely differently. When freshly sharpened it still cuts the 1/2" hemp with ~5 lbs on a 2" draw -however- the knife will sink in almost on a straight push, there is very little sawing effect. To be clear it doesn't slip/slide, it slices the rope well, it however is just much more of a push cut than a slice. To look at it another way, there is very little force exerted in the horizontal direction, it cuts very smooth. If I just had to do a few cuts then this is a nice finish, cuts well, low force - but the edge retention is too low for practical purposes in general and this stone would be very slow to sharpen. It takes on average > 5X as long to reset the edge.

In regards to sharpening, it isn't trivial to sharpen with this stone either, but the problems are almost the opposite of the Suehiro. The edge bevel is very easy to prep with almost no care for edge damage or burrs forming on the apex :



To set the micro-bevel :

-lap the stone, flush it well
-run it very wet
-use standard burr minimization



The problem is that the water will contain abrasive particles + metal which will smash into the edge. The first thing you think is run it dry but if you do this the edge has a very high chance of cutting into the stone and that simply guts the sharpness. You can be at say 30-40%, let the surface get a little dry and then cut into it, get to 50%, let it dry a little more and bam cut into the stone and the sharpness is gone. Of course if you use edge trailing you can remove that problem but then you start to have issues with pulling up a burr.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 25, 2014 12:50PM
What do you think is behind the Suehiro's greater edge retention? I would assume it's edge is less coarse than the dressing stone, and the initial sharpness was less, but obviously I'm missing something.

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 25, 2014 05:17PM
Quote
C Amber

[...]
I would assume it's edge is less coarse than the dressing stone, and the initial sharpness was less, but obviously I'm missing something.

There are many possibilities, the main ones I think are critical :

-it has passed the point where coarseness is a benefit

If this seems strange then just consider for example how edge retention in general behaves like this with many factors, carbide volume for example. The others are :

- since the dressing stone doesn't cut really well so it creates a lot of deformation (this tends to leave the edge weak/brittle)

and

-I don't think the edge is formed the same by a dull grit vs a sharp one even if it shows (and measures) the same sharpness..

This is the part that is a bit complicated (and possibly completely wrong). Imagine a serrated edge which is fully sharp and imagine another one where the points of the teeth are severely dulled -but- the inside of the scallops are still perfectly sharp. Now on many types of cutting both would appear to be very sharp but the edge retention will be higher for the first one. I think something similar is happening on the apex itself.

As for how much of all of these are a factor, the only way to know is by piling data on it and seeing what comes out.



Edited 3 time(s). Last edit at 10/25/2014 06:53PM by CliffStamp.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 26, 2014 08:59AM
Sigma Power 120 :



In short :

-very high initial sharpness
-extreme edge retention

I have only done two runs with each, I don't really plan on doing a lot more as this is more to just give some kind of range vs actually providing precision comparisons but that is why some of the error bars are so high. For example I knew the Sigma Power edge would be very sharp easily so I didn't do much burr minimization on the first run so the starting sharpness was ~50%. On the second run I actually crossed strokes and went ultra light and the sharpness immediately jumped up very close to 100%. Hence when it has such a high set of error bars.

The main point I wanted to illustrate can be seen if you look at the Sigma Power 120 vs the Naniwa Aotoshi 2000. There is no steel pairing which is that far apart, even if you look at 1045 vs M4 the performance in this kind of work (slicing hemp) isn't that different. This is why before you look at what steel gives better performance you have to look at what grit finish gives better performance. If you combine this with the apex comparison done recently then the total difference shows just how tiny steel influence is in comparison.

In more detail :

Here is the apex set during shaping at ~5-6 dps :



and in the second run :



It forms jagged but is already very sharp, easily slices newsprint with no hesitation and will hint at push cuts. To be clear, there is no attempt at burr minimization, this is just a very hard stone, cuts very well (this steel also grinds easily) so there is not a lot of deformation on the edge or fracture aside from directly related to the abrasion.

This is the micro-bevel at 15 dps :



Nothing fancy :

-give the stone a few sprays
-light passes, cross strokes

This is the apex at the end of the run :



Large flat spots, some of the original aggression remains. If you think about this you will see that even when this knife is taken to extremely low sharpness, the total width of material lost is well under 10 microns deep (as the original "teeth" are not completely worn away).

This is why in general most people waste more material in sharpening than in use because of burr based sharpening which over grinds, often until it is strongly visible. This means you have ground enough steel past the apex to actually form a visible lip.

--

As an aside, the way this stone is working on these kinds of kitchen knives is enough of a reason for me to want it if it did nothing else at all because of how rapidly it will remove damage -and- put a very aggressive slicing edge. That edge for example is perfect for a bread knife.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 27, 2014 05:41PM
awesome thread!!!

two questions Cliff...

1. what is the red bar ("iSharpness"winking smiley?
2. So the Sigma Power 120 seems to be a very fast stone at removing damage and releases fresh abrasives? I am wondering because I was thinking about having a water stone cut up to fit my WEPS paddles because I don't really like re-profiling things w/ the 100 diamonds... takes forever because it doesn't release fresh abrasives. What do you think compared to the 100 diamonds on a stock WEPS> ?
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 27, 2014 06:31PM
Quote
razoredgeknives

1. what is the red bar ("iSharpness"winking smiley?

Initial sharpness.

Quote

What do you think compared to the 100 diamonds on a stock WEPS> ?

The cutting speed isn't comparable, the 120 Sigma Power is much faster.

As for does it release abrasives, the one I have doesn't yet, however read this : [www.cliffstamp.com] .
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 27, 2014 06:52PM
Soft Arkansas from Gesswein : [www.cliffstamp.com]



Now Soft Arkansas is a very loose classification of a particular natural stone, i.e., a rock. It is made from Novaculite which is a form of flint which is a type of quartz (silicon dioxide). This is a rather soft abrasive, the hardness is similar to fully hardened martensite so it is softer than all carbide, even cementite. As a grinding stone, for coarse shaping, they can't match the speed of waterstones, or even the coarse man made India stones, but for sharpening steels they can cut well, oh they are so wonderful to use. It is hard to describe how absolutely trivial it is to take this stone and this knife and set an edge which easily shaves hair above the skin.

The edge retention when slicing hemp however isn't that high but that would be expected as the grit finish is very high, but it is so easy to sharpen there is so little reason to ever let a working knife get very dull anyway. There are downsides of course to the stone which I will talk about more when I write it up shortly, but its strengths are really strong indeed.



Edited 1 time(s). Last edit at 10/28/2014 03:43PM by CliffStamp.
KWB
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 28, 2014 02:25AM
I mean this as a serious question- what do you hope to gain in understanding with the different edge finish testing. What is the main goal behind it/ what sparked you to test edge finish? I have to say I really like the scale type graphs they are easy to quick look and follow. And I just generally like graphs.

Just following along with the different threads along here has started to make me think more about edge finish than I otherwise would have, which brings up in my mind what it is you are hoping to establish. As in my mind there is always a means to an end. As I assume you aren't just cutting up stuff and taking notes cause you think it's fun.

Contact 570-486-9095
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 28, 2014 08:12AM
Quote
KWB
I mean this as a serious question- what do you hope to gain in understanding with the different edge finish testing.

In 98/99 Mike Swaim presented data on rec.knives that the cutting ability and edge retention was significantly effected by the edge finish and that extremely coarse finishes could have a much larger effect than steel changes. I have explored this since reading his work and at times have shown this is such a strong effect when combined with others (geometry) that a knife made from a mild steel bar can easily outperform a modern super-duper steel.

Why do I do it, it is only one of the things I study, and I study what I find curious, there is nothing more to it than that. This weekend I conducted some experiments to find out why/how birds can locate food I put out around my house so quickly as it appears to be instant. I determined (loosely) that it isn't based on smell, that it is visual and they are doing it because they have identified this area as a likely feeding ground and they simply poll it frequently and they can see from places you can't see them.

--

If anyone is curious, I simply checked to see if they reacted to what I was throwing out and discovered it didn't matter, they would come for scraps of paper just as easily as nuts/seeds or left overs. The only consistent influence was location and the further I would get from the location the less likely (longer time) it would take for them to show up. It also didn't take much of a distance for them to never show up which indicates they have some kind of distance/area criterion around "feeding locations". I was not that interested to find out the exact specifics, but if you wanted it would not be difficult to map out how the area is of influence. I suspect that it is inverse root related to the area :

time of arrival =~ 1 / (square root of area inclosed by distance from primary feeding area)

I also suspected that there is some kind of co-operative behavior as birds tend to notify each other immediately once they arrive. This has strong survival benefits as it allows a bird to basically get the "average" food from a much larger area vs all of the food from one smaller one. Ironically once they are on site they tend to forget about sharing and just see who can eat the most the fastest. Gulls tend to be much easier to understand than crows as a gull once fed will just return and wait for you to feed them and stay in plain sight and eat right in front of you. Crows tend to wait until you leave. But this could be nothing more than people eat crows here, no one eats gulls.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 28, 2014 05:34PM
In regards to this experiment, realize what it gives you aside from the obvious. For example once this is filled out then when a trial is ran it can be used to essentially "measure the grit" by simply noting where the performance falls in relation to the other stones. This itself is a non-trivial application because this measurement in general is difficult for a lot of abrasives but this shows how easy it is to measure something indirectly by the practical influence it makes.

I also have a suspicion that it is also not just going to show a grit influence but also an ease of sharpening one. The stones which generate a very high initial sharpness will have edge retention boosts by it. Not as strong as the grit influence sure but there none the less. In general then I would predict that the diamond stones for example will have higher edge retention than the grit would indicate alone. How many people talk about this then - the edge retention advantage that say a Norton India has over a waterstone of similar grit, but I bet it will come out.

--

Bester 700 : [www.cliffstamp.com]

This stone is worn away to a thin slice of its one great massive form. I took it out of its semi-retirement where it now serves a valuable member of a set of reference abrasives. Like most of the waterstones it is not trivial to sharpen with at all and getting just 25-35% of optimal is satisfactory without a lot of effort. I tried one round to actually use it dry but that didn't help. While I didn't get the water slurry problem it is still a bit crumbly and it just isn't as sharp/aggressive. It lands where you would expect it :

Re: Edge retention with different grit finishes on 3Cr13 stainless
October 29, 2014 02:50PM
No-Name coarse benchstone (2"x6" ), this is the stone I often mentioned in videos and have it glued to a wood block. I often use it to flatten other stones. It is a curious case because it gets two fairly different results depending on how it is used. If I use it after I have lapped with it then the surface is usually pretty gouged up and often has coarse grit embedded in it. It therefore produces a pretty gouged up edge :



which wears pretty slowly and those pieces act like mini-serrations and keep the edge cutting for a long time :



Note how even with so much wear most of the edge is just flat those pieces are still there and will keep cutting. If I use it like this it is hard to get the apex really sharp, it will only be about 25-35% at best but the TCE will be fairly high about 4 . However if I clean the surface well then it will produce a much higher initial sharpness, pretty much able to get maximum sharpness on this class of steel and it produces a much finer edge :



However without the big pieces knocked out the edge retention is much less and the TCE is reduced to about three. This is the average :



The error bars are huge because it is almost like averaging two very different stones. This is also a pretty curious case because while it is pretty easy to get a very well refined apex it is so slow doing it that I would rarely every use it unless I really specifically needed that high sharpness for cutting light foam or similar. I would rather use the Bester 700 and take the lower sharpness in a fraction of the time. It also is just barely able to cut even this steel so using on something like ATS-34 would be like trying to walk a cat, only for the entertainment value.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 29, 2014 05:26PM
I dig out my well used King 1000 and do a little experimenting. It makes the same kind of mud as the Naniwa Superstone 400 and sure enough it produces the same kind of finish. See how the harsh parallel scratch lines are gone and it has that shot peened effect :



The very apex is a bit ragged but this is a very low edge angle (~5 dps) and I was not caring at all about the apex in this stage and this is over ground and has a coarse burr. The tricky part is now getting that apex properly formed.

I did a little experimenting and found a way to get consistent high sharpness but it is fairly time consuming. It basically is as simply as this :

-really reduce the force to the absolute minimum
-do a lot of ultra-light passes
-when the apex starts approaching push cutting newsprint then do just one partial pass at a high angle
-do a lot of ultra-light passes

I did it a few times and could get consistent results taking 50-75 pps to set the apex on an edge which already could slice newsprint freely and smoothly. It ends up looking like this :



And at that point is catching hair above the skin and can do push cuts, it has long passed what most people consider arm hair shaving sharp.

Now can you go harder, sure, and can it work, sure - but it is pretty easy to do one pass a little less that ideal, get some kind of loose slurry grating along the edge and you are back to just slicing newsprint. Again none of this matters unless you are trying to get very high sharpness, if you just want to slice newsprint all of these stones sharpen equally easy, anything can apex to that level of refinement without concern.

Another thing which became obvious to me is why Fikes and similar can cut massive amounts of rope on a push cut with those high finishes because at the end of the hemp trial, then the sharpness is pretty much gone (< 1.5% of optimal) it still looks like this :



See just how little wear there is on that apex, there is no light reflecting from the edge and you can still easily continue cutting the hemp, especially if you are a strong guy and can exert 15+ lbs with little effort. With these fine polishes, there is so little wear or damage to the edge it is trivial to restore.





Edited 1 time(s). Last edit at 10/29/2014 05:33PM by CliffStamp.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 29, 2014 05:42PM
My experience trying to get a really sharp edge off the King when I was sharpening that Santuko you also have was basically the same. Lots of really, really like passes per side, although I did deburr earlier in the process if I remember.

Interesting that you got a higher sharpness off the King than the Aotoshi...

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 29, 2014 06:05PM
Quote
C Amber

[...]

Interesting that you got a higher sharpness off the King than the Aotoshi...

That is one of the problems with some of these comparisons. You start off doing them with one set of skills and then 50 careful sharpening sessions later, not so much. I am pretty confident now I can get the same performance off of the Aotoshi, it will just take the same very slow and careful process. The only thing that concerns me is that ideally I like the stone to be just damp, but without a lot of water I have cut into the Aotoshi on occasion and so it might be a little less more involved than on the King.

As an aside I am no longer as impressed with the Naniwa Superstone 400 after discovering that the basic King resin bond does the almost exact same thing.



Edited 1 time(s). Last edit at 10/29/2014 06:18PM by CliffStamp.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 29, 2014 06:13PM
It takes a lot to impress you, so I'm not surprised.

Did you mean more and not less with respect to the involvment on the Aotoshi? I seem to be misunderstanding something...you liked the stone just damp on the King, but on the Aotoshi you need it wet in order to not cut into it?

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 29, 2014 06:18PM
That made no sense, I meant to say it would be a little less trivial or a little more involved and didn't decide in time to translate to my fingers. I just corrected it.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 30, 2014 04:47PM
Sharpmaker CBN rods :

-extremely easy to refine the apex
-moderate to high edge retention

Initial microbevel :




Worn :




Summary :



Here is a curious way to look at the TCE results, Roman graphs like this, the further you are from the center the better the results. It certainly makes for ease of immediate impressions :

Re: Edge retention with different grit finishes on 3Cr13 stainless
October 30, 2014 06:23PM
There are a few interesting things coming up for example where would the red brick I used in that video fall? There are also some pretty curious things but which would require a lot of work to investigate. What would happen if this was repeated with S90V, with M4, with 10V? What would happen if the micro-bevel time was limited to say 15 seconds and you did some kind of efficiency ratio results as Kyley has suggested?

Look at this representation :

Re: Edge retention with different grit finishes on 3Cr13 stainless
October 30, 2014 06:43PM
The color on this last one is really nice. Provides a very big impact along with the sizes.

And agreed on the interesting-ness of it. I think what strikes me the most is something related to what you said in the thread currently talking about the Spyderco forum...there is no "good", "bad", "worse", "better" etc without context. It seems crazy to say a "no name" stone could be as good as high end Spyderco CBN! stones, but yet, in this context it is.

_______________________________________________________________________________________________

Always in search of a good choppa'
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 31, 2014 04:45AM
Quote
C Amber

[...]

It seems crazy to say a "no name" stone could be as good as high end Spyderco CBN! stones, but yet, in this context it is.

Yes, the context is critical. For example if you compare it to the Bester 700, then the No Name has superior :

-rate to dishing
-resistance to gouging
-ease of refining the apex

but inferior :

-ease of flattening
-rate of material removal, shaping

If I wanted to set a micro-bevel there is no question as to which stone, similar if I wanted to do significant grinding, but they are complete opposite answers. In general the problem tends to come when someone has a particular focused viewpoint and they just answer/evaluate according to that.

For example the guys that sharpen in a traditional Japanese way and end with stropping on ultra-fine compounds on balsa or similar. They would have no use for stones like the No Name, the only things they look for are :

-raw cutting ability
-particular finish (mainly for the large flats)

Often they are not even concerned about rate of wear as they flatten aggressively. Hence they would just judge the No Name as useless / poor - and it is in the context they sharpen. The critical thing then is realizing what is being said are not absolutes but often they are pretty much claimed as such.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 31, 2014 06:48AM
Cliff,

In each of these trials you used the same stone to apex and micro-bevel. Would you expect these results to change if you had one stone to set the apex (whichever stone) and used the different stones to just set the micro-bevel? Basically, what I'm asking is the relative influence of the stone as used for apexing vs. micro-beveling in these trials.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 31, 2014 07:18AM
Quote
Steel_Drake
Would you expect these results to change if you had one stone to set the apex (whichever stone) and used the different stones to just set the micro-bevel?

That is a good question and the answer is yes and it was something I only thought about mid-way through. The reason is has such an influence is that a very coarse stone sets a very coarse and jagged edge and this will be *much* more so because of the low angle than the micro-bevel. In short this means if you compared these :

-edge refined to Naniwa Aotoshi 2000, then Sigma Power 120 microbevel

vs

-edge and micro-bevel, Sigma Power 120

The second one would have much better edge retention in the work done here than the first one. I need to go back and clarify which stones were used on the edge and which ones were only the apex.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 31, 2014 08:35AM
Quote
CliffStamp

That is a good question and the answer is yes and it was something I only thought about mid-way through. The reason is has such an influence is that a very coarse stone sets a very coarse and jagged edge and this will be *much* more so because of the low angle than the micro-bevel. In short this means if you compared these :

-edge refined to Naniwa Aotoshi 2000, then Sigma Power 120 microbevel

vs

-edge and micro-bevel, Sigma Power 120

The second one would have much better edge retention in the work done here than the first one. I need to go back and clarify which stones were used on the edge and which ones were only the apex.

As usual, let me reply to see if I understand what you're saying:

Are you saying that micro-beveling a very coarse apex with a coarse stone will produce a coarser micro-beveled apex than micro-beveling a fine apex with a coarse stone?
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 31, 2014 08:54AM
Quote
Steel_Drake


Are you saying that micro-beveling a very coarse apex with a coarse stone will produce a coarser micro-beveled apex than micro-beveling a fine apex with a coarse stone?

Yes because the edge under the micro-bevel has a more coarse finish and the micro-bevel won't completely erase it. Essentially the roughness produced by a given grit is inversely proportional the the grinding angle. A lower angle gives a more coarse edge. This is one of the reasons why lower edge angles indirectly raise edge retention on slicing as even if you micro-bevel with a finer finish it will likely still retain some of the irregularity of the more coarse finish. It also means you get a strong compounding effect on edge retention if you lower angles and grit finishes at the same time because :

-15 dps, 5 microns

vs

-5 dps, 50 microns

The second one gets a much rougher finish because of both the reduction in edge angle and grit finish and the effect combines in multiplication not addition so it gets severe fast. This is why I was easily able to get the same edge retention with a < 55 HRC 3Cr13 knife doing slicing cuts vs the 10V/63 HRC Farid/Spyderco. I just reduced the angle and grit finish on the 3Cr13 knife, this allows for a gain on the scale of 100:1.



Edited 1 time(s). Last edit at 10/31/2014 08:57AM by CliffStamp.
Re: Edge retention with different grit finishes on 3Cr13 stainless
October 31, 2014 03:34PM
MXF DMT - 6 micron : [www.cliffstamp.com]

This is a bit of a curious stone to talk about in regards to ease of sharpening because it is so fine. In the first round I ground the edge with the 1000 King as prep for the micr-bevel :



However while the apex line is decent, this DMT stone is so fine it takes awhile to refine that ~15 micron finish even with a microbevel. The second time I finished it with the Naniwa Aotoshi 2000 first and then micro-beveled, that worked much better. This is the edge after the cutting round :



There is very little damage of any type to the apex after the cutting, a simple steeling and it is at near optimal sharpness again. However and this is the critical part, the knife has to be very sharp before the MXF DMT or basically it does nothing as it cuts so fine.

The edge retention however is low as would be expected in slicing abrasive media as it is so fine :



I would hope that it should be obvious that using this type of cutting and similar slicing cardboard doesn't give a complete picture of edge retention, it basically only shows half of it. On this type of cutting the rule seems to be obvious that :

-edge retention is inversely proportional to grit size

However in general not all knives are used for just slicing and so in general the 120 Sigma Power isn't always the best choice even though it dominates the above. If these knives were used for carving hardwood then the push cutting edge retention would like invert completely hence why chisels and plane blades don't tend to be sharpened with such a coarse finish.

There is also a little bit of curious behavior as the edge retention of the MXF DMT stone is a little higher than the waterstone of a similar finish, the Naniwa Aotoshi. I would suspect in general this would be true because the edge would simply be more optimally formed with a more consistent parallel scratch pattern.
Re: Edge retention with different grit finishes on 3Cr13 stainless
November 01, 2014 07:16AM
Spyderco Medium :



I have had these rods for a long time and they are not much smoother/finer than they were initially. I had meant to recheck them using the same way I estimated the grit size initially and will likely recheck that as well. However the way they perform here is also an indication that they are a finer grit now than the original estimate of ~12.5 micron :



and just the TCE :



I have also started doing additional runs with some of the others which is why the spread is decreasing. I never intended to however there are some curious little details coming up that I am curious of. For example is the MXF performance spike real, if so then why?

Aside from edge retention this stone (Spyderco Medium) is simply near ideal for setting / refining an apex :

-can not be gouged
-is resistant to extreme pressure
-does not need soaking
-rate of wear is extremely slow

Now for grinding/shaping, is is almost as poor as it is good at refining the apex.
me2
Re: Edge retention with different grit finishes on 3Cr13 stainless
November 01, 2014 08:42AM
Either the Sharpmaker Medium or the Norton Economy fine are my usual finishes now. I use the Sharpmaker fine white stones for the Tojiro and for a few occasions where I want someone to get wide eyed when the see an edge. I generally dont go for high slicong like the focus of this thread. My 220 Norton waterstone is a very good coarse edge, though as mentioned here, it is a process to get very high shaprness off it, though some more practice would help. Do you plan ontrying the DMT Xcoarse?
Re: Edge retention with different grit finishes on 3Cr13 stainless
November 01, 2014 04:44PM
Quote
me2
Do you plan ontrying the DMT Xcoarse?

Yeah, I will run the DMT's I have at some point.

In general I don't finish with a finish so niche based as the Sigma Power 120 simply because that you lose as much push cutting performance as you gain in slicing. For kitchen knives Spyderco Medium is very nice, or MXF DMT. For general utility, 600 DMT.
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