Let's talk about the Cast 440C used by the Serrata

[Fred Sanford]

Hey folks,

Been a while. I am very interested in this knife but I don't know what advantages or disadvantages cast 440C has. I believe that it means that the molten steel is poured into a mold and then left to cool. However I am not sure how the non-cast knives are made. Is it just cold rolled steel and then it is stamped out or laser cut?

I have always liked regular 440C so I just wondered if this cast 440C is supposed to be better or what? I love the design of the knife as well Stuart! Great stuff.

[v8r]

I like mine a lot. It takes a really nice toothy edge. I believe the cast 440 has a larger grain structure that gives it these properties (if I remember correctly).
All in all a cool knife that does a lot of things well.

[Stuart Ackerman]

As-poured 440C cast steel, was discovered by David Boye to have toothy edges...
When you hot or cold roll it, as per normal manufacturing methods, it does remove the toothy-ness...BUT it did make it tougher overall...

Therefore a Serrata wil not lever as well, but there are tools built for that purpose.. ( crowbars etc )
Cliff Stamp has a Serrata for testing, and in time he will be able to compare it in his carpet and cardboard cutting exercises...
He might see this thread and pass comment?

I tried to "converse" with Mr Boye when I started my research, but I never managed to make contact via email...
I still regard him as THE pioneer in 440C cast steel...yes I know that steel makers were experimenting long before he did, but I have to give credit to him...

[Fred Sanford]

Cool. Thanks Stuart! I appreciate it. Hopefully Cliff will pop in.

[Cliff Stamp]

However I am not sure how the non-cast knives are made. Is it just cold rolled steel and then it is stamped out or laser cut?

Most steel will be forged in some manner simply because it has to be put into basic shape (sheet for example) for use. It is also usually thermally cycled to prepare for the final hardening (annealing or normalizing). David Boye strongly promoted cast 440C, later cast Cobalt alloys and there is no arguing that he could not do some impressive things with knives. However he also :

-ground much thinner than most makers
-used low grit finishes

If you combine the two of them together you get extremely powerful slicing ability and edge retention on a slice. Boye was doing this in the 90's. If you really want to see some extreme geometries then have a look at his drop point hunters. I don't think he makes them any more but they were at the limit of what I have seen anyone do with steel. They were full flat ground and the edges were almost micro-bevels, < 0.005" at times.

As the cutting ability was so high they would continue to cut even when dull, far better than many knives fully sharpened. As the edge was so narrow and the material fairly basic (440C) it could be sharpened almost instantly on even basic stones. A fine india was a decent finish and could get there very fast.

[Cliff Stamp]

Cliff Stamp has a Serrata for testing, and in time he will be able to compare it in his carpet and cardboard cutting exercises...

Nice to see you reference Boye, far too many people don't give credit where it is obviously due.

I have user the Serrata a few times for stock comparisons, however the problem is that the stock geometry lowers its relative performance, or so I believe anyway. I zero'ed the grind, but even then it is a pretty shallow ~10 dps blade bevel about a cm high. Now I am not going to argue that a thicker cross section in general makes an inferior knife, that would be as silly as saying a sneaker is better footware than a sandal - it depends on what you want/need to do. However the problem is that most of the other knives I have are ground different enough that there is a disparity in the force.

I believe that the extra force in the cutting is likely to produce higher pressures around the apex (increased side torques for example) and this will accelerate blunting. I have a few other knives of similar cross section which I sent out on passaround and when I get them back I might run them against it. Or I might bring the blade bevel up on this one. I do like the general design for a lot of work. I struggle to try to find work which would maximize the utility of the stock thickness which is synergistic with the steel. I can see lots of work for heavier stock, but 440C, cast or not, isn't what I would want in that kind of knife.

I think it would be interesting for a knife like the A. G. Russel Deerhunter in d440C.

[Wanimator]

However I am not sure how the non-cast knives are made. Is it just cold rolled steel and then it is stamped out or laser cut?

Most steel will be forged in some manner simply because it has to be put into basic shape (sheet for example) for use. It is also usually thermally cycled to prepare for the final hardening (annealing or normalizing). David Boye strongly promoted cast 440C, later cast Cobalt alloys and there is no arguing that he could not do some impressive things with knives. However he also :

-ground much thinner than most makers
-used low grit finishes

If you combine the two of them together you get extremely powerful slicing ability and edge retention on a slice. Boye was doing this in the 90's. If you really want to see some extreme geometries then have a look at his drop point hunters. I don't think he makes them any more but they were at the limit of what I have seen anyone do with steel. They were full flat ground and the edges were almost micro-bevels, < 0.005" at times.

As the cutting ability was so high they would continue to cut even when dull, far better than many knives fully sharpened. As the edge was so narrow and the material fairly basic (440C) it could be sharpened almost instantly on even basic stones. A fine india was a decent finish and could get there very fast.

Why not do a sprint run folder with this then?

[Cliff Stamp]

Indeed, I like the Chaparral but I am overly fond of wire clips :

https://www.spyderco.com/catalog/detail ... roduct=672" onclick="window.open(this.href);return false;

There may be some concern about gross blade breakage as the steel is cast which tends to significantly lower fracture toughness and bend fracture strength. This is why Boye used high stock thickness as well, ~1/4 " .

[JD Spydo]

When I first got into Spyderco knives back in the mid 90s there were a few models made with 440C ( not cast) and by no means do I think it's junk steel at all. I used to get my Spyderco "Q" model ( which had 440C) really sharp and it would hold an edge well. My only gripe with 440C ( cast or conventional) is that with all the newer/better supersteels that Spyderco has blessed us with I just don't see why you would want to use 440C>> unless it was the have significant advantages for hunting and outdoor uses>> I truly wish the SERRATA would have had M390>> the more I use that steel on my recently aquired Military model the more it's becoming my #1 blade steel. As much as I liked the XHP Military I have to say that the M390 is significantly better IMO.

[Stuart Ackerman]

JD
Have you cut anything with a Serrata yet?

[Stuart Ackerman]

"Plain old" 440C is a more than acceptable steel for me...even as a straight hot rolled steel off the mill...

Investment casting it, enlarges the dendrite structure, making it more toothy...but one loses a bit of toughness as a trade-off...
Yes, there are other steels that others regards as the bee's knees...there will always be a more super "super steel"...

If I had found that VG10, ZDP189, or any other steel has the ability to be even more toothy that 440C, I would have used that steel...
I did trail a few others, and they were worse...VG10 was almost as good, but bear in mind that my test methods were basic...

I prefer toothy on any blade, regardless of steel type...
I have no need for a shaving edge...and easy to sharpen is more important to me, than a blade that takes forever to get sharp after use...
I feel that for me... the Serrata was and is a win/win...cuts well, and sharpens easy... :)

[Cliff Stamp]

"Plain old" 440C is a more than acceptable steel for me...even as a straight hot rolled steel off the mill...

I think in some ways the differences in steels are often heavily distorted. If you look at the material properties of 440C vs VG10 or ATS-34 or even S30V they are not that different. Even if you do CATRA measurements you end up with differences on the order of ~10%. A person just cutting would have a very hard time trying to see that small of a difference and thus for practical use it is very hard to tell those steels apart in the properties that they are similar (hardness, wear resistance, toughness). It is thus odd to see people refer to 440C as some kind of low end/sub steel and S30V as some kind of high end steel when the differences are on the order of ~10%. Just imagine talking about differences in general in that way.

Have you tried D2, that has an extremely coarse carbide structure inherently. If you wanted to go really extreme then look at the higher D series steels however at some point you might have practical machinability concerns. A really curious experiment would be to look at casting something like A11 which is normally a PM steel (10V). Did you ever look at the cobalt alloys? Boye ended up switching completely to them over 440C but never really expanded on why, aside from the obvious fact that are essentially corrosion immune in normal environments. They are a lot softer/weaker than the steels though but if you are just cutting soft media then this isn't an impossible choice.

[Stuart Ackerman]

The Serrata project was expensive for me...

I did look at cobalt once I had "cracked" the 440C casting process...

To source a bunch of Cobalt would have added to the cost...the melting points are about the same...
Contamination of the crucibles was another aspect that the casters were concerned with...
Yes Cliff..the actual differences between steels have being distorted by most folk...10% is not a big figure to contemplate by any means...

I provided a few yachties with 420, 440C, VG10 and 12C27 steel blades, and no one knew the steel types apart from me...I made all the knives...eight in total...paraglider shroud wrapped handles in Kydex sheaths...
They were free to sharpen any time that they wanted to...and swap around the knives when they wanted to compare...and most felt that I have provided the same steel to all of them...only one lady thought that a 12C27 blade sliced tomatoes better than the rest...

In life, most folk do not count how many cuts they made...they probably apply more pressure, and then eventually realise that yes, the knife needs sharpening...

[Stuart Ackerman]

And yes, to the unasked question...if Spyderco did the Serrata in Cobalt, that would be interesting... :)

[Cliff Stamp]

[...]
In life, most folk do not count how many cuts they made...they probably apply more pressure, and then eventually realise that yes, the knife needs sharpening...

I tried a long time ago to see if I could extra data from the sharpening I did for friends and family. It sounded like a great idea. I had a single blinded huge data set of different knives, steels, and I could apply different angles/edges. The problem is that there was not enough power to discriminate, it basically didn't make any difference what angle I used, what grit I finished with and eventually I found it didn't make any difference as to the quality of sharpening. What I found was that people brought the knives back on reasons that had nothing to do with how sharp they were but other reasons and the did not want it to be too frequent as I don't charge for it.

In the Serrata, did you go with full tang for the balance, or the raw weight, or the strength in extremes or some combination of all of them?

[Stuart Ackerman]

Full tang for strength first, and then balance...the ones I make are lighter than the Spyderco version, but the handle cavities are essentially the same...

http://ackermancustomknives.com/wp-cont ... rata12.jpg" onclick="window.open(this.href);return false;

Spyderco makes their version a bit thicker...and the grind is thicker..., my unsharpened edges are 0,3mm before sharpening...

[Cliff Stamp]

Stuart,

I can appreciate the balance issue as handle based balance points offer stability. However the strength I am not sure is functional. It is very difficult to load the internal part of the handle significantly without over loading the blade. Have you seen failures in partial tangs?

If you have the time/inclination, I would like to see a short video where you use the knife for the typical work which you feel requires the cross section, or is optimal for it.

[Phil Wilson]

Cast 440C blades as in the Serrata have their own personality. In my experience very easy to sharpen and are very aggressive cutters. Given the grain structure it is somewhat surprising that they are also very durable. A bit of history and update:
The Boye cast 440C knives are still available through http://www.francineetchedknives.com" onclick="window.open(this.href);return false; . Francine did all the art etching on David Boye's knives in the 70's and mid 80's. She now obtains the castings from David and still does the etchings on the finished blades. She has a world wide following and her finished knives are beautiful. For a while I was doing the heat treat and grinding for her and another maker was doing the handles and sheaths. These were flat ground to an average of .007 behind the edge. As far as I know no knives were ever returned with edge damage. This included a variety of small utility up to 6 inch length and also 6, 8 and 10 inch Chef blades. JP Holmes (RIP) continued after me and did the heat treat and grinding for about another 2 years. Again no reported blade failures since JP and I were in contact since we lived in the same area. I have two Chef's from David's castings in my kitchen and love how they cut and the ease of sharpening is a bonus. Just a few strokes on a SC fine Norton and very light strokes on the India and back in business. Just as Stewart says. Phil

[Pinetreebbs]

JD
Have you cut anything with a Serrata yet?

I have one in the kitchen. In spite of it's hefty blade it's a great slicer and easy to keep very sharp.

[Cliff Stamp]

Phil, thanks for the link. I have been looking for one of Boye's knives for a long time.