Opinions on Sanvik 13C26 steel

[Larrin]

This depends on the austenizing temperature used. If you note in the above the hardness used of 57/59 is well under the maximum hardness of 13C26 which means it is being either undersoaked or overtempered or not oil quenched or cold treated or a combination of all of the above. These can cause cause less chromium in the ferrite because it will either have never been dissolved or will precipitate out as secondary carbides. They are better off going with 12C27m at that hardness as you will get it with more corrosion resistance, 13C26 which is designed to be ran harder. Do you have the dissolved C/Cr percentages for 154CM, S30V and VG-10 at their normal hardening temperatures?

-Cliff

The hardnesses of 57-59 are probably overtempering, though this is of course just a guess. Uddeholm (maker of AEB-L) actually recommends higher tempering temperatures. It's interesting the differences between what Uddeholm recommends and what Sandvik does. The last section of Verhoeven's book has the dissolved Cr and Mo percentages of 154CM, and in other sections lists 440C, 13C26, 12C27, 19C27, and several others. I used those numbers to estimate those of S30V and VG-10. S30V is a little easier because you at least have the chromium carbide volume to go off of as well. From everything I've been able to figure out, the best case scenario says that S30V and VG-10 could nearly reach 13C26 when it comes to chromium in the matrix, but my estimates say that they're lower, more in the 10.5-11.5% range.

Edit: Of course, if the companies are using using unusually low austenitizing temperatures, or using slow air cooling combined with no cryo, this could mean lower than normal corrosion resistance. These steels especially seem to benefit from faster cooling rates and cryo.

 

[Cliff Stamp]

I would be interested to know how you are estimating because some of those carbide interactions are quite complex. You can get crude estimations by doing something as simple as assuming for example all the vanadium will carbides and calculating the reduction this has on the carbon and then seeing which tie line that C/Cr pseudo-steel falls on, but this would just be a rough ranking, not something you would use to actually infer material properties. You also need to include the effect of the nitrogen in S30V and the higher dispersion inherent in powder metallurgy.

Sandvik actually has those steels specifically listed as knives so likely has better optomized heat treatement. However they like most are adverse to cold treatements and thus it biases their perspective. Note for example that they will avoid high temperature soaks because it leaves too much retained austenite. However as noted by Landes this is necessary to obtain maximum performance but you also then need oil/cold to prevent carbide precipitation on the quench and minimize retained austensite. Generally manufacturers are looking at cost minimization for large scale production. A custom knife maker, or even small shop production would not follow the same goals.

In general the lower hardness tends to come from lower soaks, because when you go high enough to get a lot of the chroimum into the austenite it makes it prone to heavy retained austenite, plus the hotter you run the furnaces the harder it is on the equipment. However hotter tempering temperatures would also allow heavier grinding after finishing which would be attractive to manufacturers.

-Cliff

 

[Confederate]

So what's the bottom line?


.

 

[DGG]

The bottom line is, "It depends."

 

[Confederate]

Yeah, Cliff's message appeared the same time mine did, so I hadn't read it. But it does sound like a definate "It depends...."

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[STR]

I have knives of both 12C27 and 13C26 and have to say I'm very impressed with both. The Storm II I bought and wrote a review about here some months ago is a fine knife in the 13C26 steel and one great edge keeper. I've been very happy with the performance of it, especially when you consider the steal it is to buy one.

I recently bought and EKA knife from World Knives and a couple of Thinus Herbst custom folders out of South Africa that came up for sale here on the custom for sale forums that are the 12C27 and to be honest I didn't much care for the handle on these but the blades of this steel are fantastic.

I have trouble seeing much difference in edge keeping from one of these steels to the other. Both seem up there with the best D2 knives I have and use often and believe me I don't say that with hesitation. They hold their own with the super steels as far as edge retention and ease of sharpening based on my own experience with these knives.

STR

 

[Larrin]

I would be interested to know how you are estimating because some of those carbide interactions are quite complex. You can get crude estimations by doing something as simple as assuming for example all the vanadium will carbides and calculating the reduction this has on the carbon and then seeing which tie line that C/Cr pseudo-steel falls on, but this would just be a rough ranking, not something you would use to actually infer material properties. You also need to include the effect of the nitrogen in S30V and the higher dispersion inherent in powder metallurgy.

Sandvik actually has those steels specifically listed as knives so likely has better optomized heat treatement. However they like most are adverse to cold treatements and thus it biases their perspective. Note for example that they will avoid high temperature soaks because it leaves too much retained austenite. However as noted by Landes this is necessary to obtain maximum performance but you also then need oil/cold to prevent carbide precipitation on the quench and minimize retained austensite. Generally manufacturers are looking at cost minimization for large scale production. A custom knife maker, or even small shop production would not follow the same goals.

In general the lower hardness tends to come from lower soaks, because when you go high enough to get a lot of the chroimum into the austenite it makes it prone to heavy retained austenite, plus the hotter you run the furnaces the harder it is on the equipment. However hotter tempering temperatures would also allow heavier grinding after finishing which would be attractive to manufacturers.

-Cliff

They are general calculation, I didn't use any set formula, but I still feel I have a pretty good idea. Either way, I don't particularly care, 13C26 has very good corrosion resistance.

Actually, Sandvik likes high austenitizing temperatures, especially in older literature. They recommend austenitizing temperatures as high as 2050F if done with cryo.

I myself like lower austenitizing temperatures for greater toughness and carbide volume. In many cases a lower austenitizing temperature with a lower tempering temperature used to give you the same hardness as one with a higher austenitizing temperature and higher temper, the lower austenitizing temperature will give you greater toughness due to lower carbon in matrix (see 9V data sheet, and Carpenter PM M4 toughness vs. heat treatment graph). Verhoeven shows in his book that the lower the austenitizing temperature, the greater the carbide volume in AEB-L, while still being able to reach 63-64 as quenched. Higher austenitizing temperatures will of course give you the greatest hardness and corrosion resistance. With AEB-L/13C26, the heat treatment possibilities are incredibly interesing because of these many ideas. The point I'm making is that at the same hardness, the higher carbide volume will yield greater wear resistance. IMO, with different heat treatments, 13C26 could be used in just about any knife application. It won't have the very highest of everything, but it can have a very good combination of properties for just about anything. It's probably the toughest stainless that can still reach 64 Rc as quenched. As a side note, have you seen the Verhoeven artlice on damascus edge retention? It shows AEB-L beating out both wootz damascus and 52100 in CATRA testing, which while maybe not the end all, be all of edge retention testing, it does make a good case for 13C26 having edge retention that will make a great knife.

 

[Cliff Stamp]

With AEB-L/13C26, the heat treatment possibilities are incredibly interesing because of these many ideas.

These are general issues to any steel, there is nothing unique to AEB-L in that respect.

The point I'm making is that at the same hardness, the higher carbide volume will yield greater wear resistance.

This is an odd path to take with AEB-L as it actually contradicts the main point Verhoeven and Landes make about such knife steels. High primary carbide fractions don't increase edge retention uniformly because they just tear out of the edge at low angles and lower push cutting ability. The common materials tests done on the steels don't translate because the edge geometry vs carbide size is a very different scale than the standard samples. The main benefit of AEB-L is that when austenized very hot the C/Cr ratio is so specified that it leaves little to no primary carbides, similar with other sandvik knife steels. This is opposed by the 440 series which are designed to retain large and aggregated chromium rich carbides. If you want more wear resistance as Landes has noted you don't undersoak as this also reduces corrosion resistance, you switch to steels with a high dispersion of non-chromium rich carbides.

It shows AEB-L beating out both wootz damascus and 52100 in CATRA testing, which while maybe not the end all, be all of edge retention testing, it does make a good case for 13C26 having edge retention that will make a great knife.

I place little value on CATRA testing for a person until we are cyborgs, it ignores side loading and edge deformation fatigue which dominate edge retention in hand. However dased on work I have done with 12C27m I would expect AEB-L to have few complaints about edge retention if properly heat treated, especially by those who take advantage of its ability to run very fine edges and thus greatly magnify the cutting ability. 52100 is severely overhyped for edge retention, especially when it is ran as soft as most people do, 58/60 HRC. Wear resistance is general isn't near as critical as many think and is good to see makers like Devin Thomas speak of AEB-L and educate people that this isn't a 440A class steel as well as makers like Landes discuss how 440A isn't actually an inferior steel anyway and in fact is superior, not inferior, to 440C in many respects because of the lower primary carbide fraction.

-Cliff

 

[Larrin]

This is an odd path to take with AEB-L as it actually contradicts the main point Verhoeven and Landes make about such knife steels. High primary carbide fractions don't increase edge retention uniformly because they just tear out of the edge at low angles and lower push cutting ability. The common materials tests done on the steels don't translate because the edge geometry vs carbide size is a very different scale than the standard samples. The main benefit of AEB-L is that when austenized very hot the C/Cr ratio is so specified that it leaves little to no primary carbides, similar with other sandvik knife steels. This is opposed by the 440 series which are designed to retain large and aggregated chromium rich carbides. If you want more wear resistance as Landes has noted you don't undersoak as this also reduces corrosion resistance, you switch to steels with a high dispersion of non-chromium rich carbides.

The primary carbides of AEB-L are small just like the secondary carbides. If they were large, they wouldn't be dissolved in the heat treatment. I still have questions regarding the differences in hardness and size between the primary and secondary carbides. But generally, the fact that the volume is greater should yield greater wear resistance.

I place little value on CATRA testing for a person until we are cyborgs, it ignores side loading and edge deformation fatigue which dominate edge retention in hand. However dased on work I have done with 12C27m I would expect AEB-L to have few complaints about edge retention if properly heat treated, especially by those who take advantage of its ability to run very fine edges and thus greatly magnify the cutting ability. 52100 is severely overhyped for edge retention, especially when it is ran as soft as most people do, 58/60 HRC. Wear resistance is general isn't near as critical as many think and is good to see makers like Devin Thomas speak of AEB-L and educate people that this isn't a 440A class steel as well as makers like Landes discuss how 440A isn't actually an inferior steel anyway and in fact is superior, not inferior, to 440C in many respects because of the lower primary carbide fraction.

-Cliff

I'm not a proponent of the CATRA, it seems to only test wear resistance, and favors harder carbides because of the silica, but it does show some things, and I love any and all information I can find when it comes to knife making steels.

I'm the writer of the DevinThomas.com FAQ, though Devin did of course proof read it to make sure that I didn't say anything he didn't want me to. There were a couple errors in my original draft, and there is one glaring error still in there: it's carbide size is six-tenths, not eight-tenths of a micron, I was going by an old draft of the Verhoeven book.

Soon, Darrin Thomas and I will be doing edge retention, toughness, and corrosion resistance tests between different heat treatments of AEB-L and 154CM. I think the plan is to throw in a 12C27 blade also, just to see how much of a difference there is between 12C27 and AEB-L.

 

[Cliff Stamp]

The primary carbides of AEB-L are small just like the secondary carbides. If they were large, they wouldn't be dissolved in the heat treatment. I still have questions regarding the differences in hardness and size between the primary and secondary carbides. But generally, the fact that the volume is greater should yield greater wear resistance.

At the same hardness, yes, if you were testing a roller or similar. But in the fine geometry of an edge I think this extrapolation is problematic. While there is obviously wear on the edge when cutting abrasive materials the mechanism is very different from what is seen in industry where the primary carbides are what resists wear and the secondary carbides give strength and tend to just get ripped out in abrasion due to being similar in size to the scratches. However on blades the reverse may be true which means that a new viewpoint is needed.

Secondary carbides are always small simply because it takes a lot of time for carbides to form as they have to diffuse through the steel, and for the heavy alloys this takes awhile. When you are tempering the time that the alloy is at temperature is much lower than when it is annealed and of course it isn't as hot and thus the alloying carbide elements simply don't have enough time or energy to allow them to form the segregated carbides they do when the steel is annealed. There is a lot of chromium in AEB-L though and I would be surprised if the primary carbides as annealed were finer than in 52100 for example.

The primary carbides are a mix of K1 and K2 according to the basic C/Cr formation charts, the secondary carbides are K2. I would assume this may hold for secondary chroimum rich carbides in general.

There were a couple errors in my original draft, and there is one glaring error still in there: it's carbide size is six-tenths, not eight-tenths of a micron, I was going by an old draft of the Verhoeven book.

I doubt that is even significant, in general such sizes are means/medians. The carbide size isn't consistent, they change significantly from one to the next and in general the way they are measured is by looking at a few small samples of the steel and measuring a few and assuming they are representative of the population.

...edge retention, toughness, and corrosion resistance tests between different heat treatments of AEB-L and 154CM.

You might consider CPM-154CM instead as that is getting a push to replace S30V and could likely be the next standard stainless steel. It also has a much finger carbide size, assuming it is similar to RWL-34, so should offer the wear resistance of 154CM with much greater edge stability and be more competition to AEB-L. I would be interested in edge retention on a push vs slice at both acute (10) and the semi-standard obtuse (20) edge angles. Toughness should be a blowout, but it never hurts to confirm expectations. Responce to sharpening would be of interest as well, grindability and burr behavior.

-Cliff

 

[Larrin]

You might consider CPM-154CM instead as that is getting a push to replace S30V and could likely be the next standard stainless steel. It also has a much finger carbide size, assuming it is similar to RWL-34, so should offer the wear resistance of 154CM with much greater edge stability and be more competition to AEB-L. I would be interested in edge retention on a push vs slice at both acute (10) and the semi-standard obtuse (20) edge angles. Toughness should be a blowout, but it never hurts to confirm expectations. Responce to sharpening would be of interest as well, grindability and burr behavior.

Conventional 154CM is what we're using because we have a lot of it on hand, and part of what we'd like to know is difference between the large and small carbides when doing slicing and push cutting, plus 154CM is a good standard to go by. So far we're only going to do acute angles. Toughness, I agree, shouldn't be anywhere close. The test for toughness we're going to do is a multiple brass rod test, taking a picture at the edge with each shot, probably with a microscope. Not running the knife down the brass rod (i.e. Ed Fowler), but simply in one spot (i.e. Wayne Goddard), but then doing it multiple times and observing if any edge chipping has occured. This is the best test I can think of that will give us actual number rather than feel, plus the toughness at the edge is much more important, IMO, than how easily the whole knife breaks, though that can be important for the tips.

Edit: Differences in sharpening is also a major test we'd like to see, hence the microscope pictures. Difficulty in grinding and finishing will just be a time/feel thing.

 

[Cliff Stamp]

Conventional 154CM is what we're using because we have a lot of it on hand, and part of what we'd like to know is difference between the large and small carbides when doing slicing and push cutting, plus 154CM is a good standard to go by.

That is all valid from an experimental point of view, but considering the viewpoint of a maker do you really want your work to be outdated in a short time when no one is using 154CM? However if you do have it then it it only the cost of time to do it. You can always see the exact benefit of CPM154CM later which would be interesting itself.

The test for toughness we're going to do is a multiple brass rod test, taking a picture at the edge with each shot, probably with a microscope. Not running the knife down the brass rod (i.e. Ed Fowler), but simply in one spot (i.e. Wayne Goddard), but then doing it multiple times and observing if any edge chipping has occured.

The way this is usually done is meaningless, it translates to bend a steel an unspecified amount by applying an unspecified force and noting if it bends or breaks or returns to true when the load is applied. You are going to need to quantify the amount of force applied and the extent of the deformation. This is a measure then of basically the difference between yield/tensile failure. You might also consider a direct impact on the edge which would be easy to quantify by just having a swinging rod to which you could attach the knife and additional weights and thus look at the effects of the edge on a hard material under specific impact energies. The energy is easy to calculate, you are just using a physical pendulum.

Differences in sharpening is also a major test we'd like to see, hence the microscope pictures. Difficulty in grinding and finishing will just be a time/feel thing.

What you can do is simply measure the number of passes on the hone, which shows not only grindability but how much work has to be done to restore the edge. If the high carbide steels chip this can be more significant than the difference in grindability. The other issue is resolving burr issues and ideally you look at different hones. Can you use natural arkansas stones, do you need silicon carbide or diamonds to grind/reshape it significantly? Is there is difference in finishing with chroimum/aluminum oxide vs diamond/boron carbide? I would be interested to see AEB-L vs S30V as I don't think it would be the blowout that popular opinion would promote.

In any case it is nice to see such work done, especially if this will be released to the public along with the specific details of the heat treatment.

-Cliff

 

[Larrin]

That is all valid from an experimental point of view, but considering the viewpoint of a maker do you really want your work to be outdated in a short time when no one is using 154CM? However if you do have it then it it only the cost of time to do it. You can always see the exact benefit of CPM154CM later which would be interesting itself.

If our methods of testing pan out, then other steels will no doubt get tested. Even though S30V is in many ways the "hot steel", while 154CM has lost that title, 154CM and ATS34 continue to be used in many knives. If AEB-L happens to meet or exceed 154CM in slicing edge retention, while exceeding it in the other areas that we already expect it to (i.e. toughness), it would also show AEB-L as an extremely good steel. Not to sound like we're trying to make the steel look better than it is, but if S30V or CPM154 beat it out in all but say for example toughness and corrosion resistance, people may not be impressed. But that was never the major reason for the choice, 154CM just seemed to be a logical choice and we have a lot of it. On pure theory, I'm thinking AEB-L should win in toughness, meet or exceed in corrosion resistance, get 75-110% of the slicing and push cutting edge retention of 154CM, with AEB-L beign much easier to finish, grind, and sharpen. AEB-L already wins in cost, and it can be blanked, a bonus for large manufacturers, 154CM probably wins in availability, but Uddeholm isn't that bad about selling steel in small quantities, and a chemical analysis is usually provided with each batch. We'll find out how much carbide size affects push cutting edge retention pretty quickly. But even if it kills 154CM in toughness, it would be enough to show the virtue of the steel, because high toughness (along with high hardness of course) is the big thing that still hasn't been found in a popular stainless, though IMO S30V gets as close as we've gotten so far, at least when comparing to the former "super steels" 440C and 154CM.

The way this is usually done is meaningless, it translates to bend a steel an unspecified amount by applying an unspecified force and noting if it bends or breaks or returns to true when the load is applied. You are going to need to quantify the amount of force applied and the extent of the deformation. This is a measure then of basically the difference between yield/tensile failure. You might also consider a direct impact on the edge which would be easy to quantify by just having a swinging rod to which you could attach the knife and additional weights and thus look at the effects of the edge on a hard material under specific impact energies. The energy is easy to calculate, you are just using a physical pendulum.

The method of doing it multiple times is quite experimental, and it will be done in three different places to see if it even happens the same way every time. We always planned on using a scale and to attempt to do it the same way each time, but human error will definitely affect things, hopefully not very noticeably. A swinging rod is something that sounds intriguing, I'll have to think about building one.

What you can do is simply measure the number of passes on the hone, which shows not only grindability but how much work has to be done to restore the edge. If the high carbide steels chip this can be more significant than the difference in grindability. The other issue is resolving burr issues and ideally you look at different hones. Can you use natural arkansas stones, do you need silicon carbide or diamonds to grind/reshape it significantly? Is there is difference in finishing with chroimum/aluminum oxide vs diamond/boron carbide? I would be interested to see AEB-L vs S30V as I don't think it would be the blowout that popular opinion would promote.

We have a few different kinds of stones, including the dual silicon carbide Norton, several DMT stones, a Spyderco sharpmaker, a ceramic rod, and we're considering purchasing some good leather along with chromium oxide to experiment with extremely polished edges. Diamond paste may be somewhat better but it's way too expensive. Microscope pictures of the edge along with rope cutting results will be a big experiment just in sharpening for us. We will be taking microscope pictures after each pass (or every other pass, or whatever seems best), to show comparison, or at least that's the plan. We haven't decided on a microscope yet, though people on the Kitchen section of Knifeforums.com have had good results with an inexpensive QX5 (can't remember brand name). I was talking about grinding and polishing differences being a feel thing when Darrin actually grinds and finishes them, because grinding and finishing can many times be different than difficulty in sharpening.

I too would be interested in the toughness difference between AEB-L and S30V, we'll see how soon that happens. From a Charpy-C standpoint, I think AEB-L gets somewhere between 25-35 ft. lbs. at 60 Rc, which is a pretty large range, but it's just a guess.

In any case it is nice to see such work done, especially if this will be released to the public along with the specific details of the heat treatment.

-Cliff

Public release is definitely under consideration, the big thing is we want some writing done on AEB-L, as it is mostly restricted to the internet right now, and even here it gets little exposure. If we feel we got good results in comparisons then we will definitely go for some type of publishing, if not in a magazine such as Blade, then at least on the website.

 

[Cliff Stamp]

I'm thinking AEB-L should win in toughness, meet or exceed in corrosion resistance, get 75-110% of the slicing and push cutting edge retention of 154CM, with AEB-L beign much easier to finish, grind, and sharpen.

I would expect it to dominate push cutting severely at low angles. However it depends on how long you are going to let the edges dull. Eventually the high carbides edges will fracture so much they will be stable as the edge will have thickened. At this point then they will start to out last the finer steels with a lower carbide because there is no longer any issue with carbide stability.

You might want to consider multiple comparison points such as how much cuts until loss of shaving and how many cuts until loss of paper slicing. I am not suggesting that you use these specifically to determine sharpness but just suggesting them as class benchmarks. What are you considering geometry wise for the testing profiles?

...human error will definitely affect things, hopefully not very noticeably.

Just make sure to do repeat testing, the random errors will quickly be reduced to minimal levels. If the difference is so small that you can't detect it by hand even with careful controlled measurement there is no way it could ever be argued to be seen to be significant for a user.

I would also suggest have Thomas make the blades and give them to you *unmarked* and this way you eliminate the possibility that you unintentionally bias the results in favor of AEB-L. However since these steels are so different under the stone and in other respects you will likely figure out which is which right away. But this does make it much more valid.

I'd also be interested in higher hardness as AEB-L can get much harder than 60 HRC which you can reach with 12C27m with oil/cold. You might also want to discuss the testing with Cashen as he has given a lot of thought on steel evaluation and has a lot of equipment and may be willing to test samples in various ways.

Diamond paste may be somewhat better but it's way too expensive.

Contact DMT and describe what you are doing. Since diamond paste should have advantages in cutting the harder carbides in alloy steel they are likely to donate some abrasive to get the positive press especially if you mention you are considering publishing in blade and we are talking about a comparison with a well known and respected knife maker. Similar in regards to other abrasives. You could likely get them by placing an ad for the manufacturer on your website.

-Cliff

 

[Larrin]

What are you considering geometry wise for the testing profiles?

They are going to be thin flat ground blades, I believe they're actually going to be kitchen knives.

Just make sure to do repeat testing, the random errors will quickly be reduced to minimal levels. Just consider the following, if the difference is so small that you can't detect it by hand even with careful controlled measurement by hand would it ever be seen in actual use anyway? If you can't spot a difference there is no way it could ever be argued to be seen to be significant for a user.

Everything we're planning on has been on the basis that we will be able to do it multiple times to get rid of the human error.

I would also suggest have Thomas make the blades and give them to you *unmarked* and this way you eliminate the possibility that you unintentionally bias the results in favor of AEB-L. However since these steels are so different under the stone and in other respects you will likely figure out which is which right away. But this does make it much more valid.

This is the plan also, though I agree, it may be fairly easy to tell the difference.

I'd also be interested in higher hardness as AEB-L can get much harder than 60 HRC which you can reach with 12C27m with oil/cold.

The first couple blades will be two different heat treatments, both getting 60 Rc, to see the differences between different austenitizing temperatures. We can indeed reach 62 Rc after tempering fairly easily, and I think that's part of the plan.

Contact DMT and describe what you are doing. Since diamond paste should have advantages in cutting the harder carbides in alloy steel they are likely to donate some abrasive to get the positive press especially if you mention you are considering publishing in blade and we are talking about a comparison with a well known and respected knife maker.

-Cliff

I'll look into it.

 

[Cutshaw]

Can I add that my head is swimming after reading Larrin and CS's posts?

 

[Cliff Stamp]

They are going to be thin flat ground blades, I believe they're actually going to be kitchen knives.

What is the general goal for an edge configuration? Are we talking 0.025"/15 or more like 0.005"/10.

Everything we're planning on has been on the basis that we will be able to do it multiple times to get rid of the human error.

Minimize, not get rid of, but yes. You can never get rid of errors, they most you can do is reduce them and of course measure their extent.

This is the plan also, though I agree, it may be fairly easy to tell the difference.

You can also have Thomas keep switching the markings. For example after he makes them he puts on a small piece of tape and you do the work. After doing one test he resharpens them and give them back to you and randomally moves the tape so you never know if you are testing the same blades as before or not. If you have multiple samples then you do something similar with a,b,c,d or 1,2,3,4. This means that you don't know going into any test anything concrete about the outcomes.

You might also want to consider the use of a well known benchmark like Bos doing the heat treating of the 154CM or at least some of it to serve as a comparison. This adds a well known reference point to the work. Not to say that Thomas can't heat treat to Bos's standards, just simply that it is more well known and removes one of the possible opposition arguements. As well specific materials testing on stock samples. Charpy, tensile, etc. . It would be really informative to see which properties were linked to which aspects of performance.

-Cliff

 

[Larrin]

What is the general goal for an edge configuration? Are we talking 0.025"/15 or more like 0.005"/10.

I'm not sure, I know they'll be ground to zero, and the grind will start at the top of the blade. All of them will be the same, and that's the main thing I'm worried about. Darrin makes thin flat ground slipjoints (with the occasional fixed blade), and my father makes thin convex fixed blades (mostly hunters and kitchen knives), so a comparison of thinly ground knives that are as close to the same as possible is good enough for me. I like thin grinds too. While not for every application, it is the grind used for most of the knives they make, and for 90% of the applications we use knives for.

Minimize, not get rid of, but yes. You can never get rid of errors, they most you can do is reduce them and of course measure their extent.

Of course, just a few misplaced word choices.

You can also have Thomas keep switching the markings. For example after he makes them he puts on a small piece of tape and you do the work. After doing one test he resharpens them and give them back to you and randomally moves the tape so you never know if you are testing the same blades as before or not. If you have multiple samples then you do something similar with a,b,c,d or 1,2,3,4. This means that you don't know going into any test anything concrete about the outcomes.

Something else to take into consideration. :yawn:

You might also want to consider the use of a well known benchmark like Bos doing the heat treating of the 154CM or at least some of it to serve as a comparison. This adds a well known reference point to the work. Not to say that Thomas can't heat treat to Bos's standards, just simply that it is more well known and removes one of the possible opposition arguements. As well specific materials testing on stock samples. Charpy, tensile, etc. . It would be really informative to see which properties were linked to which aspects of performance.

We've been the slightest bit concerned about the 154CM, as we haven't heat treated nearly as much of it as we have AEB-L, so sending it to Paul Bos is something we're considering, but since we can heat treat it ourselves we've so far decided not to spend the few extra dollars, though we can always change our minds.
As soon as Dick Barber gets his test lab up and running, inundating him with everything from micrographs of damascus to carbide volume of AEB-L to toughness testing of various materials is all something we're quite interested in, though a full range of Charpy, tensile strength, etc. testing could get expensive, and require a lot of material. I think for now we will stick with our own testing, and working with Dick Barber will tell us more in the future. By the way, seeing how much adding 302 with the AEB-L affects performance in damascus is on the list as well, and will probably be a ladder pattern to have a consistent edge.

Talking about adding all of this extra testing is fun and all, but we can only do so much just starting out. Materials, time, extra tests, etc. add up pretty fast as I'm sure you can tell us.

 

[Cliff Stamp]

Talking about adding all of this extra testing is fun and all, but we can only do so much just starting out.

An accepted fact is that you will learn through experimentation. Don't wait until you have developed what you think is an ideal method because the time you could have spent gathering data would be much more valuable and is far more efficient at optomizing methods anyway. I can guarantee that in a short time you will regard early work as crude, but that is experimental science. You refine as you go.

In regards to materials testing, Cashen has an impact testor and the equipment for detailed microstructure analysis. Considering how vocal he is about placing demands on makers for rigerous testing to support promotion it would seem likely that a collaboration with him would be of benefit when you have a maker willing to do it but lacking some of the materials equipment.

If there is a university near by it is also very probable that you could either just do this by talking to the technicians in the materials department, or for published work actually approach one of the researchers and discuss a direct collaboration. Considering you are doing all of the work and they would get the publishing benefit it should not be hard to convince them to participate.

-Cliff