3V:Why aren't more companies using it?

[Cliff Stamp]

... I think we could all agree that 3V...with proper heat-treat...is superior for a fixed blade!

There are no "superior" blade steels. Mel Sorg was one of the first makers to use 3V. This was before Bladeforums existed. He was a pretty direct guy and very low hype, just solid information. He found 3V was not better than 5160 for his large blades nor better than D2 for his small blades. It was basically something which did both things ok and thus make a knife which fit inbetween a pure heavy use blade and a pure fine cutting tool. All steels are like this, they will excell at some things and be readily outperformed at other tasks by others. If you find any maker/manufacturer selling you on the fact that a steel is just directly superior then move along as that is a line of nonsense. It is like saying one edge angle is optimal irregardless of what you plan on doing with the knife.

Is it any harder to work than S30V?

S30V has more carbon, more chromium, more vanadium and more molybdenum. The grindability is so low that Crucible has even suggested that makers/manufacturers may be overheating it and this is causing the problems with chipping. 3V is expensive and hard to grind compared to steels like 5160, however when it is compared against common high alloy tactical steels then it is neither. There are guys making those types of large knives out alloys like 10V, S125V and T15. These alloys are way harder to grind than S30V and way more expensive.

-Cliff

 

[thombrogan]

This "Tuff" folder is planned with heavy titanium scales with a compressor frame lock. This piece will have an unusual geometry incorporated in the blade to with stand alot more torsion and prying, and a larger stronger pivot...

I want a folding prying cutting mathingy with an integral Compression Lock!

 

[Ed Schempp]

Cliff has made some very valid points about trade-offs and choices in steel. I felt in these applications that toughness was very important. I foresee the possiblility and probability of someone who uses any of these three knives; that it is the largest strongest tool availible. It will probably be used to beat on stuff and pry. These three designs using this material fall into this knife/tool catagory.

Crucibles numbers are 70 for charpy at a harness of 63RC, I plan to have the steel heat treated to 59-60 RC. I believe this will drive the charpy number up some more. This steel is often substituted for S-7 in die application according to Dick Barber the designer of S 30V. In this application it out preform S-7 even though it charpies at a lower number. This wear resistance should be an assest in the field. Field sharpening will have to rely on diamond and ceramic to efficiently preform that task.

One of these blades is a ten inch camp competition design. Normally blades of this size have be effectively heat treated in the 54-56 range. I believe that 3V at 60 will give comparable toughness to 5160 at 54 RC and give superior field performance...Take Care...Ed

 

[Cliff Stamp]

Concerning the charpy-c notch responce of 3V, Crucible gives it in the the PDF file which shows it from 58 to 62 HRC. For edge durability I think torsional strength and toughness tests would be more suitable because that is the way edges tend to take damage, large choppers in particular tend to take a chip or ripple when the blade turns in a cut, in particular on a hard knot or glancing blow off a limb in heavy ingrowth.

One of these blades is a ten inch camp competition design. Normally blades of this size have be effectively heat treated in the 54-56 range.

That is interesting I always assumed they were much harder. I look forward to a Spyderco version of the knives. It would be appreciated if you would talk a little about the design behind the production piece, issues of cross section, balance, mass etc., why you went the way you did to achieve the performance you desired.

-Cliff

 

[J.Davey]

"If you find any maker/manufacturer selling you on the fact that a steel is just directly superior then move along as that is a line of nonsense."

Cliff, I have always respected your work and your knowledge, but you seem to contradict yourself a bit with the prior comment. I read your stuff all the time and you have often sang the praises of INFI and SR101 as having the best of both worlds (toughness & edge holding). Isn't this the same goal as 3V? Maybe S7 would be better?

 

[M Wadel]

i dont think s7 is good for knives. supposedly tough but no edgeholding whatsoever

 

[Cliff Stamp]

INFI provides a nice combination of toughness, wear resistance and corrosion resistance for a heavy use blade steel. It is however possible for a user to value one of these properties much higher than the others which would mean INFI would not be the optimal choice. It isn't as tough as S7, as wear resistant as 10V or as corrosion resistant as D2.

In order to know which steel is superior you have to know what exactly is going to be done, what aspects are highly valued and which are not. My main point is that you should always keep in mind that steel (and geometry) is always a question of what are you willing to lose as well as what do you gain. Too often the former is ignored compared to the latter which can lead to hype readily.

When 3V was given a push a few years back many tactical makers found it rusted far too readily. This lead to a reputation for low corrosion resistance which was a bit misleading because it was being compared to stainless and not other tool steels. However for those that needed high corrosion resistance 3V was not a superior choice.

A lot of people also freak out if you mention hitting a knife with something hard or chopping into something hard so for them an extreme impact toughness obviously has no value.

-Cliff

 

[Redguy]

So Cliff, what steel would be the optimal choice for a very heavy duty small fixed blade? (Not a dedicated slicer.) Assuming the heat treat is right, are there any better choices for good impact toughness, yield strenght and edgeholding with adequate corrosion resistance than CPM3V?

Thanks in advance.

 

[Cliff Stamp]

i dont think s7 is good for knives. supposedly tough but no edgeholding whatsoever

The "S" series steels are actually designed for shock, that is what the "S" stands for, they are used in jackhammer bits and similar. They have a low wear resistance but that does not mean they have a low edge holding. For knives that require such toughness that you would discuss those steels, wear resistance tends to be of little benefit because that is never the critical mode of failure.

As an example, using the Cold Steel shovel, with a proper edge grind and honed to a high sharpness, I can cut and limb out dozens of saplings and buck many sections of dead seasoned woods and still cut fine vegetation with no problems, wood simply isn't very abrasive. Now if that steel was replaced by something which was more wear resistant but not as tough the edge retention would go down and sharpening time would go up.

Most of the wear resistance=edge retention comes from metallurgy texts which have *assumed* fracture isn't an issue and typically their "edges" don't have the same geometry as knives and the "sharpness" isn't as high. Consider how blunt the edges on a die or hacksaw would have to be worn before they would stop being used compared to a knife edge for example.

...what steel would be the optimal choice for a very heavy duty small fixed blade? (Not a dedicated slicer.) Assuming the heat treat is right, are there any better choices for good impact toughness, yield strenght and edgeholding with adequate corrosion resistance than CPM3V?

As a user, if you have not found acceptable performance in the high wear tool steels like D2 because you are seeing problems with fracture I would recommend first the A series steels or the general purpose work steels if you don't care about corrosion resistance like L6. Note increasing wear resistance doesn't prevent edge rolling or deformation and thus if you are not getting good edge retention because the edge is deforming then moving to a high wear steel of similar hardness isn't going to be a major advantage and it just costs more and it now takes longer to remove the edge deformation.

If you are not getting high slicing edge retention in that class of steel then I would suggest you work with geometry / grit before switching steels. Stock profiles can be improved in performance by hundreds of percent by tuning to the specific user requirements. This can make much more of an improvement than switching steels. A2 at a more coarse finish for example will readily outslice D2 in both initial sharpness and edge retention. I would not suggest the expensive steels without a solid base on edge geometry / grit and how material properties influenced performance.

Personally I have little value in wear resistance for heavier use knives because sharpening tends to be dominated by repairing damage and thus wear resistance tends to be a drawback because the low grindability increases honing time when you have to repair damage. I do like very wear resistant steels for small knives cutting abrasive materials though so steels like D2 and 10V make very nice blades to slice cardboard for a long time.

I would be interested in CPM-1V for a hard use steel. It can obtain 57/59 HRC with a wear resistance exceeding A2. The toughness is extremely high (based on Crucibles limited statistics), exceeding 3V with much better machinability/grindability. I still hold that 3V has potential but the blades I have used had problems and I would like to see more materials data from Crucible and some actual comparisons to standard benchmarks from those promoting it. Have Paul Bos beat treat a A2 blade for example and use that as a benchmark.

-Cliff

 

[Redguy]

Thanks Cliff. :thumbup:

Have Paul Bos beat treat a A2 blade for example and use that as a benchmark.

With the shipping and handling that would cost me even more than a decent CPM3V blade from a well respected custom maker, so this is not an option for me.

Mr Schempp,

Are there any plans for a slightly smaller version of your knife? Even the one with the 7 inch blade is way too big.

 

[Cliff Stamp]

I was just using Bos as an example of a well known maker and A2 is a known tool steel. Anything similar would do for the makers wanting to provide concrete performance statements. Just use a local well known tool steel and quality heat treating service. Users of course can't be expected to do this type of work, whatever honest feedback a user gives should be appreciated and they can't be expected to purchase other knives for specific benchmarks.

-Cliff

 

[Ed Schempp]

The camp competition knife I designed is made from 3/16 material and has a median ridge geometry. This piece in production should come in under one pound. I tend toward speed verus weight in cutting. The edge has varible geometry, thicker at the tip and plunge than belly. I can achieve simialar edge geometry with 2/3 the thickness of most blades in this category. Some of the competition knives are 3/8 of an inch thick on the spine. The primary edge geometry was developed from my rope cutting blades. I find that if I go over about 14.5 oz: I can't move the blade as fast and I can't cut as much rope. Because this piece is fairly thin I wanted a very tough steel. Spyderco and Crucible have a very good working relationship and I was to choose from their line-up of steels. 1V was not availible to me, so I thought the best choice in their line was 3V.
Wayne Goddard has done a lot of testing on edge geometry and makes quite a few big knives. Generally Wayne likes 5160 run at about 56 RC. Wayne has developed machines for edge geometry testing and has generated a lot of good data. He probably has done as much or more testing as any maker.
I also was interested in making a knife that was not just competitive in the cutting competition but I wanted a good back country blade that would perform exceptionally well in the field. The tests and the tasks are similar for both categories. Is the best knife for an all around cutting competition good for all around out door use? I think there is a huge amount of overlap in the needs of the blade in both categories.
Being that these blades would probably be the largest tool a person would probably have with them I feel the toughness and durability issues were priorities...Take Care...Ed

 

[Sal Glesser]

Good thread. Thanx.

Hi Ed, thanx for sharing info.

Spyderco will have samples of the 10", the 7" and the "Tuff" folder at the Blade show booth.

I might add that Ed Will be governing the shape of the grinds for each of the 3 models.

sal

 

[muzzleup]

FWIW:
I have 4 of the Fahrman 3V knives which came sooo sharp that no touch-up or polishing was necessary.

Remember, that Fehrman TOOL & DIE is a T&D shop first and a knife maker after that. I think that a tool and die company would have all the information that they needed to choose whatever kind of steel that will fit the bill. I trust Fehrman Tool & Die and their choice of CPM3V and am amazed at how the knives perform.
If you will go to this link, http://www.survival.com/html/hood_hunter.html and scroll down to the fingernail pictures you can see some of the torture testing that Fehrman has done with their knives. It Impressed me!

Ciao
Ron

 

[Cliff Stamp]

The camp competition knife I designed is made from 3/16 material and has a median ridge geometry.

What do you mean by this exactly, usually I have seen it used to refer to the symmetrical apex points of daggers and such :

http://www.olddominionforge.com/dagger0117041.jpg

The primary edge geometry was developed from my rope cutting blades.

What kind of thickness and angle do you normally run at the edge and will the Spyderco production pieces be similar?

1V was not availible to me ...

I don't think it is marketed as a knife steel by Crucible, they are focused highly on wear resistance. 3V on paper certainly looks promising, though as noted I think more data would be useful. It would be very nice however if Spyderco could release a version in a much simpler steel because there are not a lot of production pieces of that nature. Most of the large knives tend to be geared more towards utility than cutting pieces so it would be nice to have a quality production piece without the cost overhead of 3V. A stainless version in 12C27m (or equilavent) would be nice as well.

-Cliff

 

[Ed Schempp]

My main influence of the median ridge geometry has been derived from Japanese pieces. The cross section of the blade is an offset diamond shape. The ridge is about 2/3 up from the edge to the spine.

The exact thickness of the thinnest part of the edge before sharpening is in the 15-25 thousandths range, depending on the steel. The final dimension is empirically derived through testing. I cut dry lalac branches past three forks of the branch. This puts alot of torsion on the edge as the branch bends in odd multiple changing angles under the pressure of the cut. Every cut presents a new range of torsion. I find the failure point and then thicken the edge until it shows no damage to the blade.

As Crucible will be a co-sponsor of my competition efforts I chose from their product line. Bohler, Timkin Latrobe, Carpenter and other all make a suitable product that could fairly be substituted for 3V, but my allegiance is to Crucible for their support to the cutlery industry.

1V may be a viable alternative, but with less edge holding. The right choice of a San Mai steel from Japan would be a good choice, providing I could get an appropriate ratio of core to clad. I like to chose the balance of the synergy of the steels. There are many viable choices in steel. I believe that for pushing performance, to be competitive in the ICCT, 3V will be a very good start. My competition blades have been made with a 52100 core. I often use 15N-20 as a clad.

I'm in total agreement that there is no perfect steel; we are all looking for the "Exclaliber Effect" ( performance beyond expectation)...Take Care...Ed

 

[Jerry Hossom]

I don't think 1V would be a good choice. I and Rob Simonich tested it when it first came out and found that it experienced plastic deformation quite easily. A chop into hard material would fold or ripple the edge, even at Rc57-59. This same occurred with Questek's M60S at Rc60. This is one reason why you can't look at composition and/or measured parameters like hardness and draw too many firm conclusions.

I've not made a competition blade yet, but I have some CPM-M4 with that in mind. I also believe that CPM-3V and S30V would make good choices as well. Each of these steels would, in my opinion, require somewhat different edge geometry, but all are excellent for heave chopping. I agree completely with Ed that blade speed is a pivotal element of effective cutting, and have only rarely (~1% of my total) used steel thicker then 3/16" even on very large blades and short swords.

IMO the excaliber effect resides in the hands of the maker and the arm of the user - neither are magic.

 

[Cliff Stamp]

I and Rob Simonich tested it when it first came out and found that it experienced plastic deformation quite easily. A chop into hard material would fold or ripple the edge, even at Rc57-59. This same occurred with Questek's M60S at Rc60.

Darrel Ralph described the exact same behavior with CPM-3V. Did you check with the manufacturers of those steels and compare your results to the relevant materials statistics?

This is one reason why you can't look at composition and/or measured parameters like hardness and draw too many firm conclusions.

Of course the yield points can be different for different steels at the same hardness and the responce to tempering can in general be highly nonlinear which is why you would examine the compression/tensile/torsional strain data as well as the impact numbers to find the optimal temper responce. This is why as I noted in the above it would be nice to see more data from Crucible because the toughness/wear resistance of 1V looks far more attractive for a large knives than 3V and often you can't infer much from the sparce materials data provided compared to the wealth of data you can look up for something like W1.

It will be interesting to see what comes out of the competitions steel wise and specifically if any of the steels allow a thinner cross section at the edge or are the winners just dominated by the skill of the cutters and the blades all very similar in design. This is why it would be nice to see the blades submitted and cutting performed by a independent individual as well as cutters using stock blades so the people and the blades could be evaluated individually. As well blades could just be rotated and the scores totaled to as well prevent raw cutting skill from being used to massively hype a particular steel which is very likely to happen. They could also discuss methods of evaluation with someone like Kevin Cashen who is of a mind that you can evaluate a blade and remove the large influence of the weilder.

-Cliff

 

[Ed Schempp]

My 3 rope cutting designs evolved with experience and testing. My last rope cutter won two competitions that I didn't participate. This fact has help validate and give me confidence in the design...Ed

 

[Jerry Hossom]

I won't comment on the Darrel Ralph results other than to say that was at a time when the heat treating parameters and nuances of CPM-3V were not generally available to knifemakers. I do however recall that Darrel said he "wouldn't have his name associated with the steel." I held a different view.

The results with M60S were confirmed by metallurgists at Questek, and hence the steel is not currently being promoted for knife use except in highly specialized applications. The CPM-1V results were acknowledged to be consistent with their expectations by Crucible's former Chief Metallurgist. In both cases the total carbide content of the steels was deemed insuffient to provide the needed strength, resulting in the plastic deformation noted.