13C26 Razor Blade Steel -- a Kershaw Junkyard Dog II Review

Cliff Stamp said:
Some things are very linear (like compressive strength), some things are HIGHLY nonlinear like toughness and corrosion resistance. I have examples of graphs on the website. Wear resistance is linear in some steels but can be peaked in others, those with secondary hardening for example. If you want specific examples just ask.-Cliff
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Well I am thinking about how this applies to STR's statement that it would be hard to tell a difference between 13C26 at 58-64.5 HRC. From your answer it sounds like it would be possible (though unlikely) for a steel to show little change between 58-64.5 HRC. Does anyone have any information about how 13C26's characteristics change through HRC points?

I do think that an average person would have some trouble distinguishing between the harder and softer steel for several reasons. One, most people don't take quantitative measurements of sharpness. Second, most people would be working with a thicker edge. The thicker edge is inherently more stable, and thus wouldn't allow the harder 13C26's greater edge stability to shine.

Thom, do you think you could have guessed the hardnesses of the various Storms you had?
 
I can tell you from personal experience that S30V at 57 is a completely different animal than at 60.5. I had a knife rehardened and was able to compare the 2 hardnesses. The difference between 3.5 points on the HRC scale was nothing short of astonishing. You send me 2 knives that far apart (8.5 points), I'll bet I could tell you which was which in 10 minutes.
 
I'll just pop in here if you don't mind and add that when I say that I am sure some read it and shake their head. Cliff obviously did. But I think it is like this. Generally speaking when you increase the hardness on a blade I think its because you plan to make a little more effective use of the steel's ability. In other words you'd think at the various hardnesses that the blade geometries would also change. Idealy that may be the case but we are talking about experimental prototypes with a company testing some various ideas. Some panned out some didn't. Heck some were probably complete flops you know?

Anyway, the point is that the geometries didn't change from one to the next. The 60 and 64.5 Rc blades were basically identical other than hardness. I didn't see a difference in them that was noticable. Believe me I know the difference between 58 RC and 64.5 Rc is huge. I was just as puzzled as anyone but in the end I simply have to report what I saw which was no real noticed difference from one to the other at the factory geometries.

STR
 
That's a good point. There's nothing quite so satisfying as a hard, thin blade. When I re-hardened mine, I definitely thinned it out, and that was my first introduction into high performance. Haven't looked back since! :D
 
Thank you. Finally someone believes me. I mean come on. I've no reason to lie about this you know? Its just what I saw. I scratched my head over it a couple times too. Actually I thought that maybe Thomas was testing me somehow at one point just trying to see if I was honest or not. No offense Thomas. I think ThomB thought the same thing to be honest. Its just that when you see something in testing, regardless of how stupid it makes you look you still have to report it. Test it again to verify that you haven't lost your mind first of course, which I did but if its still coming out the same way then you've no choice but to write down the results and say whatever with your hands up in the air and tell it as it was.

I don't like being the brunt of the 'nonsense' jokes believe me but I guess someone had to be. All I could tell Thomas was that there was really not a noticed advantage in my mind to making them harder from a performance standpoint at that edge thickness. And I'd have to check but I believe thats just what I reported almost word for word. I do readily admit that I loved the 64.5 Rc blade and thought it walked on water initially though. It wasn't until I finally took to using the other one that wasn't that hard that I realized it really didn't until ThomB thinned it down a lot and then it took off to a whole new league in my hand. Now its still one of my all time fave carry knives just for that reason.

STR
 
I believe you. I've seen quite a few things testing that made me do it again the next day. Some of them I liked, some of them I didn't... I still get very different results than most with S30V, but let's not start *that* up all over again... ;)

I try to do at least 3 runs, and preferably on different days. Some days I'm really *on* with my sharpening, some days, I just have to quit and have a beer, and pick it up again later. I'm starting to wonder how much my sharpening style (and other variables) influence the results I get for the steels and hardnesses I test.

What I really want is to test, then have someone else perform the exact same test, and compare results. I often don't trust my results. Gunmike1 has done a little of that with me.
 
I used the EdgePro at the same angles each time on the blades and did them each the same way with the same stones. Thom said he had trouble getting the 64.5 one as sharp as he'd like after thinning it down. I don't recall all of it, seems its was something about the bite he didn't think he could get as he'd like. I know it was not exactly shaving sharp to where it would take off hairs but it stayed that way a very very very long time which was quite impressive. Again I don't know that the softer blades would do this at the same thinner profiles. They might who knows but I am not going to be the one to find that out.

Once I dulled the harder one I did manage to get a very impressive edge back on it finally and was quite pleased. Its still impressing me with the edge keeping but I can say that about the Groove, the JYDII and JYD in the Sandvik steel also. Overall edge keeping is very good with all of them. They touch up nice and easy to a nice crisp edge again also. I still don't think I've ever used better steel for cutting old carpet. My D2 blades get beat up pretty bad by carpet but this harder Sandvik blade doesn't reflect near as much light back in big spots all up and down the edge like I've seen in other steels I've done that same cutting with.

STR
 
I find it very interesting that the 64 rc blade didn’t take as good of an edge as the 60 rc one did. Did you and Thom use the same abrasives? I’ve found when you want to get a good polish at a low angle you really have to make sure you have done enough work at the lower grits or else you have a hard time at the polishing level. Sometimes I have to almost start all over at the lowest grit to get the edge ready to polish.

There really can be a big difference from theory, controlled tests, and real life use What may seem like a large difference in a controlled test, example 120 cuts compared to 100 cuts, can very well be an unnoticeable difference in real use. So really a proven factual better knife can often be equal to a knife that doesn’t factually perform as well.
 
STR: Did Thom thin down both a 64.5 and a softer one? If so are they a similar thickness behind the edge? Also if so have you noticed any change in their relative edge retention since they were thinned?

P.S. I believe you.
 
No. Thom only worked over the harder blade. The rest were sent back to me just as they went out still as they were from the factory.

The 60 RC StormII Thom had is in Iraq now. So is one of the smaller Storms along with a couple of the other knives Thomas sent me.

The last one, which was the 58 RC blade was also given away when Thom said he didn't want it. I offered it to him first because of all of the ones he got from me he thought that one was the best. He kept calling it a 'ringer'. I still wonder if he believes it was really that soft.

The one Thom thinned down is the only one other than a factory edge one at the same hardness that I kept. The factory edged one I have here at 64.5 RC measures .029 right behind the factory bevel pretty much all the way up and down the blade. The one Thom got was about the same before he worked it over. In other places it was .028 but its close all the way up the blade also.

The one Thom thinned is down to .019 toward the tip .018 and .017 in the middle thinning to .016 toward back of the blade.

This difference in thickness made all the difference in the world I think. I might add the edge keeping and edge stability seem the same to me even this thin. Slicing even the hardests woods is a joy with this blade now, and we are talking big satisfying chunks of wood flying off with ease with this thing. I really love it now! I mean so much so that I wouldn't loan this to my brother you know. Its mine! I spent a great deal of time cleaning it up after Thom got done with it. Honestly he did a great job getting it thinned down but he burned out a bit I think and basically informed me he was almost sad at the condition of it. I still plan to do something special for him to replace the stone(s) he had to have gone through to do what he did to it.

I didn't worry about the finish on it at all once I got it back from Thom and felt bad that Thom felt bad about it. I mean as a user it was wonderful. In fact I used it that way for a good while. Then one day sitting here reading threads on my computer I just started hand sanding the blade up and down first with 200 grit then 400 grit emory cloth, then progressively moving up to 600 grit where it really started to get to the point that I could see my teeth in the blade using it as a mirror. I probably sanded it for a little while everytime I sat down at the computer over a period of like three or more days. I don't even know. I just took my time. Once I got it all uniformed and even looking again I simply bead blasted it and then touched up the edge to bring back the bite, which it actually lost very little of during the blasting. It looks like the factory finish again now. I flattened the factory thumb stud and drilled a hole right through it and stuck one I like better on the blade. Then I made a custom low rider clip for it and basically made it my personalized EDC knife. I take it everywhere now. Its on my pocket right now.:D

I would be willing to bet the 60-61 blades would jump up in performance as well if they were thinned down the same way as Thom did this one but I don't see Kershaw doing any this way. I mean maybe but I think there is a general fear of making a blade too thin for the masses among a lot of manufacturers. Not everyone is going to do what Spyderco will for the junkies. And to be frank, I don't think its a good idea to thin down one in the price range of this knife as the one for the junkies anyway. I think you would be better off to focus on ones that steel junkies would be more inclined to buy in a higher price range personally.

The jury is still out on how stable the edge would be at that same thinness with one of the 60 Rc blades. It would be an interesting thing to check out I agree. Perhaps after I catch up from the massive influx of stuff I have here to do I'll try it one day. Right now though my dance cart is about as full as its ever been.

STR
 
STR, I have a Mini-Cyclone and a JYD (small one) down to .010/.015. The Cyclone's edge is .010 at the pivot end and I think around .040 at the tip. The edge is very stable and will cut cardboard "like no tommorrow". I havn't cut enought different material to really say for sure, but this is a great steel and i'm happy with the performance I get from it.

The JYD's edge stayed more consistant at .010 at pivot end to around .025 at tip. I think Brogan's sig. says it best "geometry cuts"
 
That's actually a quote from Roman Landes. Not only is he using high-tech science to bring common sense to us knifeknuts, but he's also a Bladeforums member.

'The ringer' STR bought from NGK (still had the sticker) had a thinner grind than the other three knives and a higher level of polish. It was weird that the serrated teeth in 'the ringer' took no damage flying through hardwood whereas the Dec 06 Storm (with hollow grind! Ooh yeah!) had a serration bend cutting through the same hardwood. As they say, felt wheels heal what time can't.

db,

Both STR and I use EdgePros on certain blades; especially recurves; so our abrasives lineups are probably fairly similar. For the JYD II, I use waterstones and various abrasive cloths and films over glass (it's not a recurve, so why not enjoy a cold, smooth Glasstone?). The edge I sent STR (not to mention all of the scratches no where near the edge) was pathetic. Normally, all of my edges do fun things, but not that one. There are suspicions in my head, but lack of sharpening talent or total frustration are most reasonable.

sodak,

If we do start talking about S30V again, I believe it has its place in very thin knives at its highest practical hardness, but this 13C26 with its Kershaw heat-treatment is what should be used in place of S30V for most knives with that steel. The External Toggle convinced me and the JYD II made me a believer. Won't tell you want my Ericksen mora did, though. Just not polite at all.

STR,

Folks such as Jimmy Fikes run the edges of their 1095 knives and swords at 0.015" just in case someone accidentally loans one out to Patrick Stamp (Cliff's brother) and I think they're generally single-tempered so they're not the toughest 1095 you'll see (though no one would guess and less would dare say ;) ). I think a knife not being used for clearing forests (i.e. JYD II or Storm II) could benefit from an even thinner edge. Could be wrong, though. Happened several times today already and will probably happen a few more on my way to bed. I wonder if Kershaw's sales would soar with their RC60 13C26 blades were leaving the factory with edges at 0.007"-0.01" or if their returns would soar.
 
Oh yeah. By the way the one I picked up from NGK had an 04 date on it and was an original flat grind model. I was assured by Thomas that it was one of the 58 RC blades before they increased the hardness. He knew this because of the date. It was old stock bought in 06 new.

I have noted that the smaller Storm knives are slightly thinner than the Storm II knives pretty much on everyone I've handled. Now apparently Kershaw has gone even thinner with an all hollow grind platform vs the old flat grind. I think it could be a telling thing there potentially that the hollow grind one had an edge roll in hard wood though being that thin and at around 59-60Rc. One of the thin serrations did bend right over on it. This was visible when I got it back from Thom even after it was repaired. It is also worth noting that the hollow grind knife had a thinner taller serration pattern than the flat grind one did. In other words the flat grind "ringer' that Thom so liked had slightly thicker serrations than the hollow grind one which to me explains why it didn't bend when the thinner one did. However the test would need repeated to see if its the same results could be duplicated. I never had any other issues with the knife after that in anything I used it on.

STR
 
Here are a couple of shots of the thinned down 64.5 RC Kershaw Storm II Thom thinned down that I changed the thumb stud on and added one of my custom low rider clips to.

Later Thomas W sent me another of these knives in the same hardness (factory thickness) that had the new more rubber like inserts in the handle which I liked much better than the skid guard material they used previously so the entire handle side of that second knife was swapped with my custom thinned one since I planned to carry it more and keep the second one in the safe for a rainy day. I am pretty sure that the picture here shows my custom one with the original skid guard inserts if you can even make them out.

Lastly I want to apologize for my part of the way this thread took a turn. I just don't like seeing it and couldn't stand for the way a friend and respected knife person in the industry was being treated.

STR
 
Cliff Stamp said:
Yeah, purpose built. For tacticals I don't see it doing well (in general) as there you need a heavier edge and then you have inherent stability and thus you just go with 154CM+ class steels. This of course has been done to death with the many S30V vs 420HC comparions (would anyone even debate that now) but the point remains that 420HC has a much higher edge stability inherently. It will be interesting to see if threads like this induce people to stop with the "AUS-4 is junk" threads.
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..... exposing my ignorance :eek:
(I am definitely outclassed by the real steel experts here) -

many of us are led to believe generally the higher the carbon the better the steel -
hence the desireable (and marketing) term "High carbon" used in stainless steels.

What this long thread had me seeing is that generally "not so High" carbon stainless steels seem to have higher edge stability -
case in point -
Sandvik 13C26 - C=0.68%, Cr=13.0%, Mo=0.70, Ph=0.025, Si=0.40, S=0.01, HRc=57-59 (for Kershaw)

Another blade steel that seems to have a reputation for attaining good sharpeness and good edges is the Victorinox SAK steel -
but also well known to be on the "soft" side at only 56HRc
Vic SAK "INOX" steel - C=0.52%, Cr=15%, Mo=0.50, Mn=0.45, Si=0.6, HRc=56 (for Victorinox)

other steels mentioned -
420HC - C=0.4-0.5%, Cr=12-14%, HRc=55-57 (=58 for Buck)
AUS4 - C=0.4-0.45%, Cr=13-14.5%, HRc=55-57 (for CRKT)

My impression is generally the higher the Carbon content - the more difficult it is in keeping the grain/carbide(?) size small,
hence the high edge stability in lower carbon content - that of course means less edge holding/wear resistance.

However as pointed out before (in this thread and elsewhere) blade and edge geometry can have "softer" steels cutting as well as harder steels .......

Which brings me back to a long held belief of mine that good blade/edge geometry is as important (if not more so) than the steel,
and when it comes to steel I think I have a preference for high edge stability and the ability to get good clean sharp edges over mere hardness or edge holding.

So IMHO - a medium-high carbon steel like Sandvik or Victorinox "INOX" steel coupled with good blade/edge geometry suits me better for normal general purpose EDC usage, than harder high carbon "premium" steels with not so great blade/edge geometries......
but then I am not really a tactical type knife person.

--
Vincent
http://clik.to/UnknownVT2007
http://clik.to/UnknownVT2006
http://clik.to/UnknownVT2005
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http://clik.to/UnknownVincent
 
Sooo... (exposing my vast ignorance here)...what is a good "all-purpose" blade/edge geometry?

I know one probably cannot "do it all" perfectly...but, is there one that will cover a lot of ground?
 
Wow that could be a whole new thread really. You'll get a different answer from everyone that replies is my guess. Some like em thin because thin is in while others like em between thin and thick because its not quite so much one you have to do a lot of baby sitting with to make sure you don't tweak it too much laterally to chip it out. I mean if you want a paring knife in your pocket ask Thom or GunMike what they like.

Personally I have little need for that kind of thinness in my EDC folder. I like the ones I currently use the most, that being the Storm II talked about by me above and the little one I built for myself using a Bob Dozier Sweetwater fixed blade shown below in teal G10. Both are medium thickness knives I'd say hovering at .015 or there abouts right above the edge bevel.

STR
 
STR said:
Wow that could be a whole new thread really. You'll get a different answer from everyone that replies is my guess. Some like em thin because thin is in while others like em between thin and thick because its not quite so much one you have to do a lot of baby sitting with to make sure you don't tweak it too much laterally to chip it out. I mean if you want a paring knife in your pocket ask Thom or GunMike what they like.

Personally I have little need for that kind of thinness in my EDC folder. I like the ones I currently use the most, that being the Storm II talked about by me above and the little one I built for myself using a Bob Dozier Sweetwater fixed blade shown below in teal G10. Both are medium thickness knives I'd say hovering at .015 or there abouts right above the edge bevel.

STR
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I like my ultra thin knives, but I always carry more than 1 type of knife, so my Manix or R2 (with a nice STR splinter picker tip on it) can take care of the heavier stuff with their .020"+ edges, while my Caly Jr. ZDP with .005" edge can take care of cutting cardboard until it gets boring. You can even cut straight into the stone with that knife and it will still outcut most any factory knife due to the thinness. Of course, thin geometry has some scope limitations. On a note somewhat related note to simpler, low carbide steels, my new favorite beater is a Byrd Meadowlark with a Tom Krein regrind to .004-.005", sharpened flat to the stone with a 15 per side microbevel. With the Spyderco medium stone it starts tree topping hairs extremely well, and just gets better as you polish it. It cuts like a demon, and if you abuse it, who cares, it's cheap to replace. The edge took damage when I aggressively cut thick plastic (with some twisting through a thick "kink") to test the limits, and it didn't chip but dented the edge some. Nothing a couple minutes on a DMT D8XX can't fix. Edge retention is impressive, if not ZDP like. Not too bad for a sub $20 folder with "cheap" steel, though the Byrd steel is very close to 13C26 on the C/Cr tie line, which probably accounts for it's good performance. In the end if I could only have 1 knife for all around carry I would probably want an edge .010" or so in a high edge stability steel, and it would cut like a champ and have good durability for my cutting chores, IMO. Something that thin used for hard core, ham fisted cutting may cause some durability issues, but I think it leaves me more than enough margin for error to not worry about blowing out the edge. If you have more Jedi like skills you could probably make due with a thinner edge for all around work, but I'm not there yet. Just my opinion, YMMV.

Mike
 
thombrogan said:
Have you compared the JYD II to any knives of similar build? How did it compare in terms of cutting ability, edge-retention, and ease of use? Do you have any other folders with a similar blade profile and size?
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With this thread having gone viral, I think a whole new thread at a later time would be better. Perhaps by then you and/or STR will run a few quantified tests of the 13C26 blades you have at different hardnesses ... IMO that would go a long ways towards satisfying the lingering questions here, and maybe even help the discussion maintain a little focus. As impressed as I am with this steel, I'd still like to see something concrete about performance with different heat treatments.
 
Right now, my cache of 13C26 is somewhere between RC59 and RC61. They take very shap edges and hold them fairly well. When they dull, they dull by blunting and wear instead of chipping and that's perfect enough for me. From my practical-yet-gadgety External Toggle to my manly Junk Yard Dog II, I'm very pleased with this steel. Maybe I'd be happier with 12C27M or its Austrian equivalent for these knives, but that's merely speculation. My wishes are for lockbacked and balisong versions of the JYD II. Ooh yeah!
 
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