CPM S30V and hardning

[Cliff Stamp]

Yes, but when they all are set to 30 degrees inclusive, finished the same way, and worked on similar materials (granted it's not a controlled test) the Para just doesn't chip like the others mentioned.

You will see differences due to steel composition, temperature variances in processing, etc. . Is this something you have observed many times or just a couple? If it is the latter it could simple be large carbide aggregates at the edge which also will come and go as you sharpen a knife which is why it can chip one time and not the other even at the same angle in the same work.

[Fred Sanford]

Does Spyderco heat treat at Golden Colorado? I never really thought about it, and figured it was done somewhere else.

Cliff, nice to see ya "bangin' it out" in here. Great knowledge.

[bh49]

The observed performance is subject to much wider tolerances, you can easily thus see a 420HC blade outperform a S90V blade simply because the cardboard you cut with one is much more demanding than the cardboard you cut with another.

Correct me, if I am wrong. Real life chance for my S30V Military to out perform S90V Military, both with the same edge geometry is fairly remote. Also I wouldn't use cardboard as the testing media due to inconsistency, unless sample size is huge

Darn Cliff. There you go again! .
You know we want to hear what we want to hear. You know better! Tell us what we want to hear so we all can agree and everything will be fine.
Everybody remain calm!

:)
Joe

+1
I am with Joe on this. Cliff, stop scaring people. :D

[Cliff Stamp]

Correct me, if I am wrong. Real life chance for my S30V Military to out perform S90V Military, both with the same edge geometry is fairly remote.

Lets be a bit specific and start with some relatively hard numbers, Spyderco Catra :

S30V : 565
S90V : 750

Now given the variation expected in CATRA this would mean the performance advantage would be on average 40% in favor of the S90V assuming your are doing similar cutting (slicing cardboard or other abrasive media) and cutting until the blades are very dull.

Lets further assume that there is no variance at all in the S30v and S90V blades, that everyone produced by Spyderco have the same CATRA results (this isn't true, there are materials and HT variances) but lets assume this variance doesn't exist - best case scenario.

If you are cutting cardboard then all of these factors influence the cutting :

-angle of the blade to the cardboard
-speed of the cut
-draw vs push
-stability of the cut (how large are the lateral forces)

then there is the variability in the medium (which is about 10:1 even on the same type of cardboard, i.e., thickness and ridged).

Lets assume now further that the cardboard is all the same, there is no variance at all it is 100% perfectly consistent (this isn't true, but again lets create an ideal case). In that case you just have the above four factors (there are others, I am just simplifying to a few main ones).

Lets also assume you are to cutting cardboard to what Chuck Norris is to roundhouse kicks, this means you can :

-constrain the angle, speed, lateral loading and draw

all to 10%. This means you can expect a total random influence of 60% (speed and lateral loading are quadratic in effect).

This means for example that you would expect, to cut on average (assuming a medium wear 1/8" ridged cardboard) :

-about 40 to 160 m of cardboard with the S30V blade (100 +/- 60)

-about 60 m to 220 m of cardboard with the S90V blade (140 +/- 80)

Now there are two ways to figure out how often the S30V blade would do better, one is to assume a distribution and calculate which isn't hard, but the other is much simpler. Imagine that you take two dice :

-a S30V dice which goes from 4 to 16
-a S90V dice which goes from 6 to 22

Now imagine rolling them and thinking about how often the S30V dice will win. You don't even need to do the experiment to know that it isn't rare.

The general rule, very general, is that if your variance in measurement (which in this case is 60%) is even of similar size to your actual difference (which in this case is 40%) you are very unlikely to actually see a difference without looking for it.

But remember, I kept making assumptions in the above, to reduce it to an ideal case, in reality it is much more variable.

But you may ask, if that really is true (math doesn't lie) how come so many people will exclaim about the greatness of a certain steel if it is really so hard to actually see? Because people are not rational - even when they try to be.

Now you could debate the numbers I used in the above and even some of the statistics as I simplified greatly, but they are small factors which would not change the result. It is humbling, but all experimentation is like that when you start learning all the things you have to do to actually make sure your results are unbiased.

http://www.youtube.com/watch?v=8-KMoyFRGPM

After I rehandled them a friend dropped by and asked about them, he wondered why I put so much work into the heads as you could buy an axe for about $20. I told him these were forged heads, oil quenched out of spring steel (this is true for all almost axes as very few are true molten cast). I had them very sharp and asked him to do some work. He went out back and made some chops and exclaimed how well they cut and how sharp they stayed.

They are just ordinary axe heads. But once he heard this and knew my history with knives/steels, he would instinctively expect the performance and if he didn't see it then it would mean he didn't have the experience / skill to do so and he would be very unlikely to admit that, he thus affirmed what I said. This of course is the moral of "The Emperors New Clothes".

All of this being said, always buy the best tools you can from the best materials you can - just keep in mind before you make a decision on what is better than what, use them for awhile to make sure that what you are seeing is true representational average, not just a bit of lucky (or unlucky) cutting.

[bh49]

Lets be a bit specific and start with some relatively hard numbers, Spyderco Catra :

S30V : 565
S90V : 750

Now given the variation expected in CATRA this would mean the performance advantage would be on average 40% in favor of the S90V assuming your are doing similar cutting (slicing cardboard or other abrasive media) and cutting until the blades are very dull.

If you are cutting cardboard then all of these factors influence the cutting :

-angle of the blade to the cardboard
-speed of the cut
-draw vs push
-stability of the cut (how large are the lateral forces)

then there is the variability in the medium (which is about 10:1 even on the same type of cardboard, i.e., thickness and ridged).
Lets assume now further that the cardboard is all the same, there is no variance at all it is 100% perfectly consistent
Lets also assume you are to cutting cardboard to what Chuck Norris is to roundhouse kicks, this means you can :
-constrain the angle, speed, lateral loading and draw
all to 10%. This means you can expect a total random influence of 60% (speed and lateral loading are quadratic in effect).

But you may ask, if that really is true (math doesn't lie) how come so many people will exclaim about the greatness of a certain steel if it is really so hard to actually see? Because people are not rational - even when they try to be.

Cliff,
Probably I wasn't clear.
When I was talking about performance, I didn't mean "home use".
I was thinking about SATRA, which unfortunately I am not very familiar. I thought that during SATRA testing variation in:
angle of the blade to the cardboard, speed of the cut, stability of the cut shouldn't be as significant as 10%. IMHO cardboard due to variation is not a good testing media as well.
What I was thing is: make hundred blank out of S30V and S90V each produced from 5-6 different material heats and heat-treated in few lots. This way to create wide range of material/hear-treatment variation. Than test, eliminating test variation as much as possible. Than evaluate performance.

[chuck_roxas45]

Hahaha, so it's all placebo and knife nut experience don't mean a thing.

[Cliff Stamp]

Cliff,
I was thinking about SATRA, which unfortunately I am not very familiar. I thought that during SATRA testing variation in:
angle of the blade to the cardboard, speed of the cut, stability of the cut shouldn't be as significant as 10%.

It is about there :

http://i7.photobucket.com/albums/y269/C ... blades.jpg

This is a CATRA result of six identical utility blades. Note the end TCC cut is about 10% in the spread. If you look at each curve you will also notice significant differences in the point-to-point measurements. Many times for example the sharpness actually increases during the cutting instead of going down, again this is just noise in the measurement. The main thing to remember is because this is a non-linear response it doesn't take a 10% influence to make a 10% difference.

In general, experimental quality equipment usually has a minimum of 1% tolerance, it is possible to get 0.1% but that is rarely used outside of the standards labs because it is extremely expensive and if you are actually trying to measure to 0.1% of effect then you have to go to extreme lengths to minimize external factors as otherwise you will just measure noise.

Note that even the CATRA machines which sharpen blades will produce a 10% variation in initial sharpness unless you have a mechanical jig because even the small influences in drawing the blades through the equipment will cause that level of a variation. Now if that is as close as you can get using that machine, how close do you think you can get by hand? Now how much do you think that initial sharpness will effect edge retention?

IMHO cardboard due to variation is not a good testing media as well.

The variation in the cardboard is easily handled due to random sampling techniques. Even if you assume that the cardboard varies by a factor of 1000% you can easily reduce this down to a 5% influence through a few similar techniques which take into account a few statistical rules such as the law of large numbers. In short, the percentage error of a sum decreases rapidly as the sum increases (i.e. just cut a lot of cardboard and draw the samples from a large pile of stock).

What I was thing is: make hundred blank out of S30V and S90V each produced from 5-6 different material heats and heat-treated in few lots. This way to create wide range of material/hear-treatment variation. Than test, eliminating test variation as much as possible. Than evaluate performance.

If you want to evaluate different factors in a simple way yes, but normally you would not make a hundred blanks, you would usually do 2-3 of each type simply due to cost/time constraints. Almost all of the makers I work with are highly experimental and they usually still only can afford one test blade. If they are satisfied with that usually they will start selling them. If the results don't come out well it is usually abandoned, again they just can't afford the time/money to repeat as it is fairly costly.

[Cliff Stamp]

Hahaha, so it's all placebo and knife nut experience don't mean a thing.

It is almost always placebo but user experience is the only thing that matters, that is the madness which is R&D.

At the end of the day, stock (machine/lab) testing has only one purpose, to predict how an item works in use because actually testing it in use is very costly, time consuming and in many cases dangerous.

But it always has to be kept in mind it can not replace actual user experience and in any case where user experience over rules the prediction then the prediction is no longer actually predicting and it is back to R&D.

There have been numerous cases where this has happened even in the knife industry. Buck for example tested the IonFusion blades on a CATRA and the results were staggering. But user feedback was consistently different. Yes there is placebo, yes there is massive variation but the results were so different even they could not explain it. There was something wrong, the CATRA results were not being predictive, it took awhile but they eventually figured it out.

(the CATRA machine has such a low lateral load that the coated edge would be stable even after the steel wore - this can't happen in use because people can't hold the blade steady enough).

In order to actually test the blades properly Buck had to step back, do actual cutting by hand and then use the CATRA machine just to measure sharpness. With the hand variably and lateral loading taken into account the experimental values now started to match user feedback.

You always have to remember what it is you are trying to measure and ensure you are actually measuring it.

[chuck_roxas45]

Awesome! I wonder how I can make my tenacious feel like a blue para. :D

[Jay_Ev]

I thought (and I could be wrong) that the blades for the Sage Series were made in Golden and the knives were assembled as a whole in Taichung. So if this were true then the hardening process would pretty much be the same I would think.

This.

It was reported here before that the blades are made in the USA at Crucible and shipped to Taichung. So,

"Do you think the hardning process at Golden is much different than at Tiawan?"

No, I would guess that since the hardening is done at Crucible, it's the same.

[tvenuto]

Cliff these are incredibly important concepts to understand, thanks for taking the time to explain. I have an engineering background, and one of the hardest things for people to wrap their heads around were tolerances and stack-ups like you gave examples of. They couldn't understand that I spent most of my time dealing with the fact that 1" is never actually exactly 1" (except when it is).

[The Mastiff]

"Do you think the hardning process at Golden is much different than at Tiawan?"

No, I would guess that since the hardening is done at Crucible, it's the same.

The type ovens or even sizes may change the way they get where they want to go with their desired treat, but I'd imagine they would try to be as consistent as they could be. Still, there can be variations in knives of the same steels for any number of reasons. To change the heat treat parameters from those selected and specified by Spyderco would require approval from Spyderco. Then testing of the blades back at Spyderco engineering to make sure they fit in the same quality control parameters. Whatever they are using over there seems to be giving us excellent knives judging by the examples I have in S30V and CPM M4. These steels require very precise time and temperatures along with more than one temper. The heat has to be done in modern vacuum or gas ( argon?) furnaces that are regularly calibrated in different areas of the furnace. Ruining someone's shipment of expensive powder steels wouldn't keep vendors in business very long. Good luck Trying to attract new companies business when word gets out, and it always does.

joe

[gull wing]

Didn't know they offered that service, I thought they were only a supplier.
So, Crucible made the steel, shaped the blades, drilled the holes, ground the bevels, and hardened them, then shipped to Tiawan.

[The Deacon]

This.

It was reported here before that the blades are made in the USA at Crucible and shipped to Taichung. So,

"Do you think the hardning process at Golden is much different than at Tiawan?"

No, I would guess that since the hardening is done at Crucible, it's the same.

I'd be curious to know by whom that was reported, if they work for Spyderco, and if you can provide a link to the post. I know Sal has said, more than once, that the S30V steel is made by Crucible in NY and shipped to Taiwan by Spyderco. However, while my memory may not be as good as it once was, I can't recall him ever saying it was cut into blades and heat treated, either by Crucible or Spyderco, prior to being shipped there.

[Ankerson]

This.

It was reported here before that the blades are made in the USA at Crucible and shipped to Taichung. So,

"Do you think the hardning process at Golden is much different than at Tiawan?"

No, I would guess that since the hardening is done at Crucible, it's the same.

There are so many things wrong in that post I wouldn't even know were to start......

[The Mastiff]

Yeah. Crucible makes the steel. My guess is that's it. Usually Niagara or someone rolls it into the sizes/thicknesses needed and ships it where ordered, from Niagara. Most knifemakers aren't going to buy a whole heat of around 80,000 lbs. Even giants like Camillus usually didn't do whole heats from the foundry.

CTS with the new steels might be shipping out smaller knife batch sized shipments for introduction purposes( and I for sure don't know if they are or aren't) but typically that's not how it works.

Niagara will buy a whole heat and roll it to sizes they think are needed, or can custom order just for you.

Great guys. http://www.nsm-ny.com/ Bob Shabala is a cool guy and is one of us knife types. :)

Joe

[bh49]

It was reported here before that the blades are made in the USA at Crucible and shipped to Taichung. So,
"Do you think the hardning process at Golden is much different than at Tiawan?"
No, I would guess that since the hardening is done at Crucible, it's the same.

I know Sal has said, more than once, that the S30V steel is made by Crucible in NY and shipped to Taiwan.

Jay,
I think that this is the age :D :D
I agree with Paul. Sal mentioned on more than one occasion that steel is made in US and shipped to Taiwan. I believe that at least on one occasion he mentioned that blades of Taiwanese made knives are made in Taiwan. So most likely heat-treated there. Crucible developed recommendation for hear-treatment procedure, but any heat-treater can tweak it to customer liking.

[phillipsted]

It's a David vs Goliath comparison without the religious stuff.

Let's randomly assign a range in edge retention from 1 to 10. A 1-3 in S90v is beat by a 7-10 in S30v. Without getting into probability (because I'm an idiot) any roll of the dice where they are comparable the S90v wins; any dice roll where it out ranks s30v numerically it wins even bigger.

Almost anything is possible. Since guarantees are rare you have to reduce variables and stack odds in your favor. In this case paying more and tossing extra dice.

You aren't going to start talking standard deviations are you, Blerv? :eek:

TedP

[Ankerson]

There would be expected to be significant differences among blades of the same steel for many different reasons, first among them is that the composition of the steel itself will vary from melt to melt. Then each heat treatment also has tolerances (in the mill) and each heat treatment in the knife also has tolerances. These variances are easily large enough that if you took a bunch of S30V blades and a bunch of S90V blades from the same manufacturer you would find some S30V blades which held up better slicing cardboard than some of the S90V blades for example.

Not really likely, but remotely possible, but that wouldn't be the norm as long as things were kept apples to apples and the variables are kept to a min.

There are variations in heat treating, tempering and even the steel itself that could be a factor, how much of a factor they would be could be any ones guess.

In the end though S30V performing better than S90V in edge retention.... Something or a number of things would have to be very wrong for that to happen.

Or the testing process was slanted to favor S30V, but the same could be said for a lot of testing processes even outside of the knife industry.

If one wants a certain outcome they can make that happen and produce data to prove it in more than a few ways, like if they need more grant money or there is Billions of Dollars on the line for example.

Then the results are flip flopped years down the road to show the true data in a different study.....

How many times have we seen and heard of this happening over the years?

[Jay_Ev]

I'd be curious to know by whom that was reported, if they work for Spyderco, and if you can provide a link to the post. I know Sal has said, more than once, that the S30V steel is made by Crucible in NY and shipped to Taiwan. However, while my memory may not be as good as it once was, I can't recall him ever saying it was cut into blades and heat treated prior to being shipped there.

Jay,
I think that this is the age :D :D
I agree with Paul. Sal mentioned on more than one occasion that steel is made in US and shipped to Taiwan. I believe that at least on one occasion he mentioned that blades of Taiwanese made knives are made in Taiwan. So most likely heat-treated there. Crucible developed recommendation for hear-treatment procedure, but any heat-treater can tweak it to customer liking.

My bad, I humbly admit my mistake, and you're right Roman, it probably is the age. It was a guess and I guessed wrong. Although the OP question specifically asked about the hardening process and not the heat treating process. I never realized those two things were the same thing. (I didn't know the rockwell hardness was something that could be changed) Again, my bad :o :o :o :o