Laminated blade steels & differential hardening

[Ruud]

Hello all,

I was wondering if there is a chance that Spyderco will be using these techniques in future (fixed?) knives:

1. Laminated steels (as used by Scandinavian makers like Helle and some other brands. C*** S**** comes to mind). It seems that knives made from laminated steel consisting of hard center sandwiched between two layers of softer steel have a very hard edge, and are a bit more flexible than knives made from straight one-type steels.
If not, then why not? It would make for a better blade, no?
2. differential heat treatment of the edge of the blade. It seems you also end up with a harder edge whilst retaining more of the allover strength of the blade.

I was thinking about possible improvements to the existing materials being used in Spyderco knives, that's how I arrived at these questions.

Consider for a moment a blade made from VG-10, sandwiched between two layers of H-1. You'd have a blade that's almost impervious to rust (save for the cutting edge itself), whilst having an extremely hard cutting edge, and maybe even capable of taking quite a lot of flexing, right?

Anyway, I'd be interested to hear your thougths on this.

With best regards,
Ruud

[jerseybounce_42]

I have a Helle fixed blade. The stainless outer layers are very soft and scratch easily. The center takes a very nice edge. However considering it is a fairly hefty knife it was disappointing to have it bend at the hilt when inserted in the vertebrate of a deer's neck at the base of the head in the course of removing said head. I guess the stick tang didn't help.

[rcbalt2]

the zdp Caly and the zdp jess horn are both laminated

[SoCal Operator]

Laminated VG-10 and H1 sounds good, as H-1 is fairly soft if it's not machined, but why not use a core steel that is not as corrosion resistant as VG-10? VG-10 holds up fairly well on its own, and it seems that a high carbon tool steel would benefit more by being laminated with H-1.
$.02

[The Deacon]

The laminate I'd like to see Spyderco try would be one along the lines of those Mcusta uses on some of their folders, VG-10 core sandwiched between two layers of stainless damascus.

[Ruud]

Aaah, yes, but you are well aware of the 'company policy' on damascus :p .
"Does it cut any better?"
Maybe if could sell a laminated damascus blade to the powers that be as increasing the 'more important' abilities other than looks that a knife should have, such as strength and flexibility. However, I doubt that that's going to happen anytime soon.
And, much as I like the products McCusta puts out there, I think that if Spyderco decides to make any future knives with laminated, let alone damascus blades, it'll probably be the large fixed blades that are more likely to chop and pry, not the smaller folders.

Oh well, one can hope.
Best regards,
Ruud

[Ed Schempp]

Where the knife is made has quite a bit to do with what kind of steel it will be. The American made fixed blades have been focused toward the Crucible steel line. Spyderco is using some BG 42, a Timkin Latrobe product. We might see some more of Timkin steels in the line-up like 52100. An edge quench might be possible with new technologies to do commercially. An induction coil could be made to heat just the edge of a design, then quench. A mar-quench using salts is probably commercially availible.

Most of the San Mai being made comes from Japan, so there is always a chance to see a San Mai blade in a Japanese made Spyderco.

The Japanese have historically derived parameters for the production of San Mai products. Most of the Japanese Stainless steel clad is 420 steel at about RC46, maybe softer. At RC 46 there are a lot of things that will scratch the finish. Most Japanese San Mai is about 1/3 to 1/4 core, on a full flat grind you see 1/3 to 1/4 of the core.

I have a different take on the material. I like to see RC on the clad about the same as the core. I like a Carbon content on the clad to be .5-.75. If the clad is spring and saw steel it will be much tougher and more resilience. You still get a synergy in the blade from benefiting from steels of two properties. I like a thinner core, like 1/6 to 1/10. This leaves the best steel at the edge but puts more emphasis on the structural abilities of the clad steel, which has been upgraded with the higher Carbon clad.

Spyderco is always bringing "new" technologies to the table. You will probably see some of the things you ask for providing it is a product improvement...Take Care...Ed

[severedthumbs]

An interesting excerpt I got from a maker about forging and differential tempering.

Forgig is an old and time honored tradetion. But the key word is old. Although some forgers are now, finaly properly heat treating their bladed, most do not. man, only temper the edge, or leave it full hard, while never hardening the spine, or tempering it. This leavs all the forging stress in the blade, with a great deal of stress between the edge and the rest of the blade One of their much used methods is to only quench the edge, This meens that the main portion of the blade isn't or hasn't gone thre the transformation from mostly iron, to steel. Very weak, and a slipshod way of working steel. Another method, is to leave the edge in a cooling solution, and playing a torch over the spine,while watching the color run toward the edge. This does indeed take skill, but the edge is never tempered. Yes I know it will pass the ABS Bend test, But the edge will crack. This is acceptable to the ABS. Many ABS makers have told me that they would never use a knife so treated themselves as they bend jto easily. They are for the test only. But with all the hype about the ABS test, many, many makers think this a superior knife. It is in fact a vastly inferior knife. Lastly, the standard practice is for a smith to heat the blade to proper temp, Quench, and then bring up to blue, or other pre determined color, and re quench, for the temper. These are old, almost black majic ways of treating steel, and have no place in the modern world. You have to hold the given type of steel at a certain temp, predetermined by the steel type, for a given amount of time. This is the hardening process. Not the temper. Which is often confused. The temper then requires a minimum of one hour, of soak at the lower desired temp, to bring the blade to a useful hardness, and to refin the grain.Most steel benefit from at least two soaks at temp. with a slow cooling in between. this cannot be accomplished with a torch, or even aquick stick back in the fire. Smiths claim that they refine the steel, in forging, by packing the molacules. This is a joke. You cant pack molacules with a hammer. This myth has been passed down for several hundred years. it no more works than Eye of Nute! Old myths dye hard. Only proper soak, at the right temp, can refine the grain, by the maker. Virtually none of the smiths do this. As far as the ABS test go. I'm sure that you are familuar with the bend and cutting test. Here's the deal. The knife must be able to be bent 90 Deg, and back again, without bending. The edge may crack. the balde may not. You can take a piece of junk yard cold rolled, non heardening junk steel, and pass this test, using nothing more than case heardening powder.Like that used on old low carbon fire arms frames. Can you use it for a good knife? Not even Close. i see reguraly, smiths talking about theuirtyues of steels that they use, but when you look many of them up in the charts, there isn,t enough carbon t gain full hardness. That takes at least 1 full percent carbon. This is what is required to transform Iron into Steel. if we took the typical stock removal blade, and tested it nixt to the Typical ABS test blade, the Stock removal blade wouldfail their test. Why. Because their test is asqued to their type of blades. Here's the deal. Take a forged blade, and put it thru the test. It will bend, and the edge will crack. It will take little effort to bend the blade. Results It passes. Say it takes 70 FT. Pounds of veverage to bend the blade. Now take an identical shaped or ground stock removal blade. It will bend, and then break. It may have taken 500 Lbs. to bend the Stock removal blade. Both knives are now useless. Even though the forged one is said to have passed. passed what, The working part of the blade is now destroyed. All that is left is a usless rellic. What about the differenct to failure between 70 Ft. Lbs. and 500 Ft Lbs. Ahhh! They never mention that part. The forged blade will fail long before the Stock removal one. Just for fun, you can take a well made and heat treated stock removal knive, place it edge down, on a soft spined forged blade and with light tapps, literly cut the forged blade in half. The smiths are all over the forums decaliring the superiority of the Forged Blade. We would be hung as makers, if we opened our mouths. Forging has become more cult, than you can imagine. And its Eazy to see Why. The majic of fire and steel. The looks of damascus. the beauty of a great hammon.( Which in it"s self makes the blade very weak.While being put fowart and strengthening the blade). The alure of tradition, becons us all. But it is dreams, myths, smioke and mirrors. If you don't believe in the superiority of modern metallurgy, Go to the Marsial Space Flight Center, boing, Lockeed, Martin Merreta, or any aero-space company, look around at all the exotic metals, and machining techniques, and Heat-treating regements, and ask them. Where are the Black Smiths. All your get is blank stares, and maby a laugh or two. But these people are very well educated. They dont deal in fairy tales.

[Ed Schempp]

My experience is quite different in the forging industry. I'm all about debunking myths. Kevin Cashen has some astute comments at his site covering these topics. I find a higher level of knowledge about metallurgy in the forging population than the stock removal guys. The forge guys are doing their own heat treating; a lot of the stock removal guys subcontract this service. Howard Clark, Don Fogg, Al Pendrey, Wayne Goddard and Ed Fowler all preach testing your product. Making good Damascus requires making good choices in materials. Thermal cycling in the knife world showed positive results in cut testing and destructive tests. My thermal cycling knowledge didn't come from the ABS, but it did come from ABS members.

Are the performance tests of the ABS the end all be all of testing? No but they are a start. They are also a performance based criteria to judge knowledge. To be in the Knifemakers Guild you have to build a consistant quality product and have good sales practices. There are no performance related tests other than craftsmanship quality for the guild. Personally I think performance tests are good.

Recent conversation with Warren Osborn, Warren reflected that he had not been as enthusiastic about knives as he had been recently when he joined the ABS to be able to compete in their cutting competitions. Warren stated that he had learned a lot about metallurgy in his search for a better performing blade.

Go check out Kevin's site and go to articles; there is some very good information about myths and reality of forging. There seems to be a lot of assumptions made by this "maker" about the forge community that is inconsistant with my experience.

The information posted by severedthumbs written by a "maker" doesn't reflect my experiences in the forge community...Take Care...Ed

[severedthumbs]

Thanks Ed, this maker who wishes to remain anonymous is very hightly respected in the knife world but it is just his opinion. I would love to hear your take on this. It seems every maker I talk with has a differing opinion. If you do care to take the time to type a few of your thoughts and email me it would be hugely appreciated.

[Ed Schempp]

At all the forums that I participate I use my real name. I realize that everything I say in the forums is in the public domain. I focus on making my comments on the positive side. I feel the "makers" statements come from anger, and seem to be based on information that is inconsistant with my experiences. I can appreciate the frustration with hype, that is why I use my own name and am accountable for my statements. I don't hold much respect for anonymous statements.

The internet has provided access for those who care to get volumes of correct information. Fraud is quickly and efficiently exposed. There are several quality forums for information from some of the best honest people on the planet. Many of the bladesmithing forums are frequented by metallugists. Not much crap passes for the truth in these environments.

I have many friends that hold the rank of Mastersmith. That earned status is part of thier resume and only one facit of the gem it reflects, not the total picture. There are many motivations for becoming a mastersmith for most that hold the rank it is career development.

There is a difference in the goals of a knifemaker and a commercial metallurgist. A commercial metallurgist is trained to look for the least expensive path to meet a stated goal. The knifemaker cost of materials is secondary and wants the best performance, not just acceptable performance. There is because of this quite a bit of raw Research and Development taking place in bladesmithing; well beyond the needs or economics of commercial steel. This is very much a shot gun approach to R&D but it does yield results. One of my friends is a researcher for General Dymanics, formerly Rocket Reseach. When we talk about metals we share the enthusiasm about the material and we share knowledge and observations. Modern bladesmithing and modern metallurgy have a lot more in common than not.

I like steel and all of its possibilities. Forging has allowed me to widen the scope of my work. I still make a few stainless blades. The application of the blade should have a lot to do with the steel choice. No one type of steel fits all uses across the board. The more we know about steel the better choices that we can make in filling our cutlery needs. As Spyderco makes more fixed blade knives I would expect for them to use steels that might not be in thier folder line-up. It is real simple. Sals wants the most appropriate steel he can get into manufacturing that is availible...Take Care...Ed

[Ruud]

Mr. Schempp,

Thank you for sharing your experience and your point of view on these questions with the rest of us.
I am glad to hear that there is a chance that we'll get to see these techniques being used in future production models. Just what I had hoped for!

With best regards,
Ruud