Sharpening S30V and XHP experience

[jackknifeh]

On my Chaparral 2 (XHP) I've had a 26 degree back bevel and a 36 degree edge bevel. On my Sage4 (S30V) I had a 26 degree back bevel and 36 degree edge bevel as well. I've had no problems with these edge angles. So I decided to lower both angles. Using the EP I put a 24 degree single edge angle on both knives but then finished the sharpening free hand. I wanted a convex, lower angle edge and the EP made it possible for me to know what the angle was approximately when I was done. My goal was to create one convex bevel on each side with no seperate, visible edge bevel. That will come when I touch up the edges the first time. So, starting with the same angles and finishing with the same angles on both knives I found the XHP a bit more difficult to get the edge to a very similar level of sharpness. Not difficult as in "hard to sharpen". It just seemed to require more strokes or more attention to detail to get the same crispness on the Chaparral as it did on the Sage4. I determined the "level of sharpness" by slicing phone book paper and paying as close attention as I could to how easy it was to slice the paper. So, the testing is not all that accurate but since this is how I test sharpness every time I sharpen I feel pretty comfortable with the sensation I get. I think I will start push cutting printer paper. One theory is to pinch the paper between thumb and index finger and then push cut the paper as far away from my fingers as I can until the paper bends instead of the edge penetrating the edge of the paper. Has anyone done this and what are your opinions of the test. I saw a video of someone using this test after stropping with different grit strops. The finer the grit (1 micron then .25 micron for example) resulted in the knife edge being a bit more refined and would cut the paper 1/8" or 1/4" farther away from his fingers after the finer grit. I'm just explaining this to get opinions on the test, not opinions on stropping with different micron strops. I've wondered what would happen if you tested the push cutting after a 1 micron strop and could cut 1/2" away from your fingers and instead of then using the .25 micron strop just continue using the 1 micron strop. Maybe that would just keep smoothing or refining the edge so you could then cut farther away from your fingers just like if you had used the .25 micron strop.

I got to rambling again. I just wanted to post my experience SHARPENING the two blade steels. The XHP was different to sharpen than S30V just like it is if I had sharpened ZDP-189 and S30V. I'll try to explain. Let's say it took 100 strokes to sharpen the S30V. The XHP took 125 strokes to attain the same level of sharpness. ZDP would have taken 150 strokes. The numbers are just examples. I didn't count any strokes. If I hadn't sharpened the Sage4 then the Chaparral one right after the other I may not have noticed any difference. I have been curious about differences in these two steels because I like both. Given my opinion on the sharpening I could assume the edge retention might be better on the Chaparral. If I were going to try to test that now would be the best time because the edges are as close to being the same as I can get them. I just don't know much about testing edge retention accurately . I could try cutting cardboard of the same type and keeping track of the distance each knife cuts while keeping the area of each blade doing the cutting within a 1" area. Or maybe even keep the cutting area limited to a 1/2" section of the edges and only push cutting the cardboard. Or should I increase the cutting area and use a slicing motion?

Does anyone have any suggestions on testing edge retention on these two knives before I use them? I don't know how much cardboard I have of the same kind. I don't know if it makes any difference but the thickness behind the edge now is; Chaparral (XHP) is .62mm, Sage4 (S30V) is .67mm. Measurements taken at the center of each blade.

Does anyone else have opinions on differences or similatities sharpening these two steels?


Jack

[darkangel55555]

Am I correct in assuming you used the stock EP stones here?

[chuck_roxas45]

Am I correct in assuming you used the stock EP stones here?

Not Jack but he probably used shapton glass stones.

[kbuzbee]

Not Jack but he probably used shapton glass stones.

Probably.

Jack, what grit did you take them to? At this point that would likely be your biggest variable as I would think the optimal grit would be different for each. (And possibly vary with media cut as well?)

This edge retention testing stuff is a slippery slope, brother. Unless you are willing to vary everything linearly you're going to come up with some very limited conclusions that may, or may not extrapolate...

ie - you find XHP holds an edge 20% longer than S30V when sharpened at 24° finished on 10,000 grit stones cutting 1/4" manilla rope on a plywood backing using 1" draw slice with these two specific knives

Vary any of those parameters and your results "may" change. You will not have universally applicable data that says XHP holds an edge 20% longer than S30V in all cases.

Not to say this isn't good information or worth doing but when I start thinking about edge testing and all the controls needed for it I get overwhelmed very quickly.

For the time and effort involved, I would much rather read Jim's testing thread and just go use my knives But, if you do it... Have fun!

Ken

[eric m.]

Cliff? :)

[arty]

Unless you do a lot of cutting in real world situations, it may be very difficult to see a practical difference in edge holding. Both steels have lots of carbon and good edge retention. I only have one knife in XHP and haven't used it enough yet to even strop it. I find S30V OK to sharpen.
In recent moves to NC, I found that ZDP 189 stayed sharp after cutting lots of cord, while 154CM needed sharpening. M4 holds an edge forever, but I can't tell you that it is better at this than ZDP, since I didn't use the knife in ZDP nearly as much. The M4 carried me through at least 6 weeks of cutting cord and opening boxes before I stropped it.
In practical terms, I would not expect much of a difference between XHP, S30V and properly treated D2. I won't rush out to get a third Chaparral 1 because mine are not XHP. I can tell you that grinding D2 is a bear, but I am not sure if this translates into edge retention advantages compared with the XHP or S30V. There is a lot of variability in the composition of D2, but heat treatment is obviously important. I wouldn't be surprised if two knives out of the same production batch showed some variability in hardness as a function of physical location in the batch...just guessing here.

[Skidoosh]

I'm re-profiling my cts-xhp mule now and after sharpening zdp-189 I find it much easier. The S30V I have to compare it to is on a Benchmade, a bit softer than Spyderco but I have not found CTS-XHP harder to sharpen. I finish it with Ultra fine stones on the sharpmaker and strop with green compound.

[78lilred]

Ankerson's results if I recall correctly, show XHP lasting longer with a more refined edge(6000grit finish). S30V in his testing made it a few cuts longer, when at a 400 grit finish.

[jackknifeh]

This post is duplicated below. Skip this one and read the next one I posted I corrected typoes and ended uup with two posts. Not sure why. I'll delete this post soon.

On the EP I used a 500 grit Shapton glass stone. I set the angle at 12 degrees per side. At this point I didn't notice anything different about the blade steel. After this stone I quit using the EP. I then started using the Spyderco fine grit 2x8" bench stone. Then the Spyderco UF and then a Shapton glass 8k bench stone. This was the last stone I used. I didn't use any strops. I did the same progression on both knives. When I started reprofiling the edges I was only wanting a lower angle on both knives. I hadn't anticipated noticing any difference in the two knives.. I did the Sage4 first and it took a really sharp edge with nothing out of the ordinary to peak my interest. Then I sharpened the Chaparral. As I said I hadn't planned on nor was I thinking about doing any comparison between the two knives. I was just re-profiling two knives. So any differences I did notice were fairly drastic because it was only through normal sharpening activity that the difference stood out. I didn't have a notepad and I wasn't taking notes or anything you might do when doing a comparison. Therefore my memory of when any difference was really apparent is vague. I don't remember thinking anything was different as I was finishing (polishing) the bevels. The only time I remember noticing any difference was when I was actually working on the edge. It just seemed like it took more effort or more strokes to get the edge to have that crisp sharpness that the S30V took easily. If this was due to XHP being a harder steel I could assume it took longer (more strokes) to remove the scratch pattern from each previous stone. I can only assume this because I wasn't paying attention to time and I wasn't counting strokes or anything. Or maybe it seemed like the XHP took more effort because other than a sandwich break or trips to the bathroom I was just sitting there wharpening while watching tv. By the time I got to finishing the edge on a sedcond knife maybe I was getting tired. I don't remember feeling tired. So here is a quick summary:

EP using 500 grit Shapton glass to set a 24 degree inclusve angle.
Spyderco fine grit to start finishing the edge to a nice, sharp finish.
Then continued with the Spyderco UP.
Then continued with a Shapton glass 8k bench stone.

I didn't notice anything different at all until I was trying to get the edge on the Chaparral (XHP) sharp. As I progressed through the stones I didn't worry about sharpness or burr removal until I got to the last stone. After I was happy with the bevel appearance I started concentrating on burr removal and sharpness. The XHP (second knife) just seemed to take more effort (more time/strokes) to get it to the point I was happy than the S30V did.

I'm not going to carry these knives today. I'll leave them alone until I decide if I'm going to do any edge retention testing. If I do any testing it won't be scientific or very controlled. At most I may wait until we have eaten pizza a couple of times. This will give me 4 pizza boxes (2 per knife) to cut up. As far as I'm concerned if one steel isn't significally better than another I really don't care how different they are. I already know I like both so if one is a little bit better than the other it doesn't matter to me when it comes to which knives to carry. As far as which knife to carry I only care about differences in edge retention betwen steels like 8Cr13MoV and XHP or ZDP or steels that are significantly different. If I cut up two pizza boxes with each knife and there isn't much difference in sharpness when finished I know both are good enough or close enough to satisfy my curiosity. If there is significant difference after cutting 10 pizza boxes with each knife then the difference would be interesting to know. I'll try to get some cardboard of the same type together but I don't know if I have it right now. Lots of cardboard here now because of Christmas but how similar it is I don't know.

Jack

[jackknifeh]

On the EP I used a 500 grit Shapton glass stone. I set the angle at 12 degrees per side. At this point I didn't notice anything different about the blade steel. After this stone I quit using the EP. I then started using the Spyderco fine grit 2x8" bench stone. Then the Spyderco UF and then a Shapton glass 8k bench stone. This was the last stone I used. I didn't use any strops. I did the same progression on both knives. When I started reprofiling the edges I was only wanting a lower angle on both knives. I hadn't anticipated noticing any difference in the two knives.. I did the Sage4 first and it took a really sharp edge with nothing out of the ordinary to peak my interest. Then I sharpened the Chaparral. As I said I hadn't planned on nor was I thinking about doing any comparison between the two knives. I was just re-profiling two knives. So any differences I did notice were fairly drastic because it was only through normal sharpening activity that the difference stood out. I didn't have a notepad and I wasn't taking notes or anything you might do when doing a comparison. Therefore my memory of when any difference was really apparent is vague. I don't remember thinking anything was different as I was finishing (polishing) the bevels. The only time I remember noticing any difference was when I was actually working on the edge. It just seemed like it took more effort or more strokes to get the edge to have that crisp sharpness that the S30V took easily. If this was due to XHP being a harder steel I could assume it took longer (more strokes) to remove the scratch pattern from each previous stone. I can only assume this because I wasn't paying attention to time and I wasn't counting strokes or anything. Or maybe it seemed like the XHP took more effort because other than a sandwich break or trips to the bathroom I was just sitting there wharpening while watching tv. By the time I got to finishing the edge on a sedcond knife maybe I was getting tired. I don't remember feeling tired. So here is a quick summary:

EP using 500 grit Shapton glass to set a 24 degree inclusve angle.
Spyderco fine grit to start finishing the edge to a nice, sharp finish.
Then continued with the Spyderco UP. Oops, I mean UF. :)
Then continued with a Shapton glass 8k bench stone.

I didn't notice anything different at all until I was trying to get the edge on the Chaparral (XHP) sharp. As I progressed through the stones I didn't worry about sharpness or burr removal until I got to the last stone. After I was happy with the bevel appearance I started concentrating on burr removal and sharpness. The XHP (second knife) just seemed to take more effort (more time/strokes) to get it to the point I was happy than the S30V did.

I'm not going to carry these knives today. I'll leave them alone until I decide if I'm going to do any edge retention testing. If I do any testing it won't be scientific or very controlled. At most I may wait until we have eaten pizza a couple of times. This will give me 4 pizza boxes (2 per knife) to cut up. As far as I'm concerned if one steel isn't significally better than another I really don't care how different they are. I already know I like both so if one is a little bit better than the other it doesn't matter to me when it comes to which knives to carry. As far as which knife to carry I only care about differences in edge retention betwen steels like 8Cr13MoV and XHP or ZDP or steels that are significantly different. If I cut up two pizza boxes with each knife and there isn't much difference in sharpness when finished I know both are good enough or close enough to satisfy my curiosity. If there is significant difference after cutting 10 pizza boxes with each knife then the difference would be interesting to know. I'll try to get some cardboard of the same type together but I don't know if I have it right now. Lots of cardboard here now because of Christmas but how similar it is I don't know.

Jack

[jackknifeh]

I posted one post then I noticed some typeos so I wanted to edit and correct them. I edited the post and saved the changes. Now I have two completely different posts. I was going to delete the first one but decided to ask about how this happens, if anyone knows. This happens to me every so often but only when I'm using my tablet. It has never happened when I'm on my pc. I'll delete the first post in a few minutes just to limit confusion. There are several little quirks I experience when using my tablet on forums. On one forum I will type a letter, then the cursor will jump to the left side of the letter and display the next characters with the first one being shoved along to the right of what I'm typing. That only happens when on my tablet and on that specific forum. Wierd. :confused:

Jack

[Donut]

It's probably all in your head. :)

[jackknifeh]

It's probably all in your head. :)

You may be on to something. :)

[bh49]

Does anyone have any suggestions on testing edge retention on these two knives before I use them?
Jack

This edge retention testing stuff is a slippery slope, brother.
Ken

+1
Testing is engineering excises, so you need to be prepared. Any testing, where you expect objective results is more complicated than most people think. You have to exclude variables, max reduce and properly estimate measurement errors, which is near impossible in home environment. Checkout Ankerson's thread on BF.
http://www.bladeforums.com/forums/showt ... -quot-rope
His method I found the best for home environment. In many cases of home testing I found that testers reported their feelings instead of real results.

[jackknifeh]

I'm almost curious enough to consider sending the Sage4 and Chaparral to some one who could accurately test edge retention. We are always talking about ease of sharpening, edge retention, etc. This is pretty interesting stuff for people interested in knives. OTOH, WHO GIVES A S***? :) About mailing my knives to someone I'm not sure I "give a s***" enough to risk them getting lost. There are several here that I'd trust to mail my knives to for testing but the off chance of them getting lost in the mail isn't worth the risk I don't think. It would be interesting though to get an unbiased comparison from someone with the tools and knowledge to test properly.

Jack

[jackknifeh]

+1
Testing is engineering excises, so you need to be prepared. Any testing, where you expect objective results is more complicated than most people think. You have to exclude variables, max reduce and properly estimate measurement errors, which is near impossible in home environment. Checkout Ankerson's thread on BF.
http://www.bladeforums.com/forums/showt ... -quot-rope
His method I found the best for home environment. In many cases of home testing I found that testers reported their feelings instead of real results.

That's what you would get from me. My post of results would be full of "IMO", "I thinks", "maybe"s, etc. :)

Jack

[jackknifeh]

I wasn't trying to attain a mirror finish on either bevel but knew that when finishing with an 8k stone the finish would be nice. So I decided to look now and compare finishes. The XHP bevel is closer to a mirror finish than the S30V. So, IMO, I think that maybe XHP polishes up nicer and easier than S30V. How's that for "feelings vs accuracy" bh49? :)

Jack

[Cliff Stamp]

Not difficult as in "hard to sharpen". It just seemed to require more strokes or more attention to detail to get the same crispness on the Chaparral as it did on the Sage4.

Is this just the result of sharpening them once?

Are the numbers you listed representative? I am not talking about are they exact, but just the correct scale, i.e. the difference is say 25 passes in 100.

The reason why I ask is that this kind of difference is on the same scale as the random difference you would expect when sharpening knives due to the effect of the level of damage to the edge in use and how much of the edge is formed by carbide/martensite/other-phases.

Remember that a knife steel is not a homogenized material, it is a big mish mash of different phases and when you sharpen a knife you form the edge through all of this and you end up with a completely random distribution along the edge. This is why when a knife blunts it often does so in a random manner and parts of it are sharp and parts of it are dented and parts of it are chipped.

I could try cutting cardboard of the same type and keeping track of the distance each knife cuts while keeping the area of each blade doing the cutting within a 1" area. Or maybe even keep the cutting area limited to a 1/2" section of the edges and only push cutting the cardboard. Or should I increase the cutting area and use a slicing motion?

The first thing you have to ask yourself is :

-what question are you trying to answer

The scientific form of this is what is your null hypothesis. For example here is a simple one :

-if the knives were used to cut a random selection from the cardboard then there would be no difference in when they started to tear the cardboard

This is a very easy hypothesis to check and only needs a few controls to ensure that you don't bias the results due to personal judgment. The main one being that you have to take care that the stopping point is well determined and not highly subjective.

There are many ways to do that, one is to find a way to put a number on it, one other is just to ask someone to check and see what they say about the stopping point when they have no idea about the steels or what was done. The other benefit this has is that it allows you to check if your distinction is meaningful. If you ask friends who are hunters, chef's, and general users and they can not see a difference in sharpness then for practical purposes does one actually exist as it doesn't for them obviously.

Now the main issue with the above question/hypothesis is that the level of significance you are checking is very low. This means there would need to be a large difference in the steels to see it. However this question for many people is the most relevant one because it is the closest experiment to what most people do in using a knife. This brings you to the second thing you have to ask yourself once you have the question you are going to design an experiment to answer :

-what does the answer to my question mean

This step is almost universally ignored and it causes one of the main sources of misinformation. People will do a comparison of some type and make generalizations from it which are completely false. For example compare to knives on rope and then infer that chopping two knives into wood can be implied. Or use a CATRA test to infer performance of knives in hand. Both of these are false because they use answers to very different questions which are not transferrable.

Here is what I would suggest as the most basic rule :

-the fastest way to learn about experimentation is to experiment

Consider this, by this time now you could have already done an experiment and if you do the experiment with an honest and frank approach and the willingness to learn and advance your methods then you will learn much more than just discussing how to do it.

The last thing is this, and this is the central idea and the most important out of all the things you have to think about and if you don't ask this one of yourself then you might as well just flip coins to make your conclusions :

-is there anything which could cause my data or my reasoning to generate the wrong conclusions and how do I check / eliminate them

This is the central and underlying reasoning of science, you have to have a way to check what you have done, not only to verify it but to also find a way to see if it was false. If you don't do this then just use a magic-8 ball because it is just as likely to generate knowledge.

Back to the steels, the main difference in them is that the CTS-XHP is much easier to generate a given hardness because it has a much higher carbon % and a much lower carbide volume. This difference is dramatic enough that CTS-XHP can be ~4 HRC points harder at a given protocol than S30V. CTS-XHP also requires a much lower soak temperature than S30V which makes it much easier to harden and the response is so high to hardening that it can have a higher hardness than S30V even if S30V has oil/cold and CTS-XHP does not.

This means if there is a difference it is likely that the CTS-XHP simply has a higher martensite hardness and lower non-martensite phases because it is far easier to obtain.

You have to exclude variables, max reduce and properly estimate measurement errors, which is near impossible in home environment.

Scientific methodology, including statistical analysis is based on knowledge not equipment, if you can not figure out how to do it at home then you are not going to magically know how to do it in a lab. The only thing equipment does for you is increase precision of measurement and does nothing at all of minimization of bias.

There is only one rule in methodology about precision which is that the measurement precision required has to be at the level required for significance comparisons. If you are trying for example to see if one object weighs more than another and you want to be able to tell if this is true at a 10% level then your measurement variability has to be less than 10%, ideally it is an order less.

[jackknifeh]

Thanks Cliff for your input. Based on it and I have no doubt that your outlook is accurate, I'm going to Wal Mart and get me a magic 8-ball. :) I'm sure those things are more accurate than flipping a coin which is also about as accurate as I'd get. :) Seriously, you are one of the people who I would consider sending my knives to for testing. I believe your results would be about as accurate as anyone elses and more acurate than most. The only problem would be that I wouldn't have any idea what you were talking about when you said anything more than XHP is better than S30V (or vise versa). :) Beyond that most of what you say is over my head as far as my knowledge of steel and testing methods.

About first sharpening? I've sharpened these knives many times. The original steel from the factory edge is long gone if that is what you meant.

Jack

[jackknifeh]

Cliff, if you meant by "one sharpening" did I sharpen both knives more than once in an effort to determine differences then the answer is no. This is the only comparison I did and I hadn't planned on doing it which is another reason my opinion is somewhat vague. Since I did get the Chaparral I've "had a feeling" XHP held an edge longer than S30V but that "feeling" may have been "just in my head" as BH suggested. Maybe my head needs some testing??? :)

Jack