HAP 40 Delica and Endura

I was the guy that asked Sal for a follow up to the Superblue Sprints on the Spyderco forums. My only lament is that it is again clad and not a solid piece. I would have paid the difference for it to not be clad. I will still probably get an E4 but will always pine for the same model in solid HAP 40
 
Well, I, for one, am excited about the Delica. When I saw this I cancelled my order of other knives to wait on this.
 
twinboysdad said:
I was the guy that asked Sal for a follow up to the Superblue Sprints on the Spyderco forums. My only lament is that it is again clad and not a solid piece. I would have paid the difference for it to not be clad. I will still probably get an E4 but will always pine for the same model in solid HAP 40
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Why? The San Mai III construction will make rust less of a concern. Claims about it being semi-stainless appear to be wrong; 'semi-stainless' isn't a real designation, but D2 is usually described as such with 12% Chromium (Stainless = >13% Cr). At less than 5% Chromium, it's probably close to CPM M4. It does have relatively high levels of Molybdenum with 5.4%, and that helps with corrosion resistance, but IDK... the cladding seems like a premium feature to me, not a cost-saver.
 
Sikael said:
Why? The San Mai III construction will make rust less of a concern. Claims about it being semi-stainless appear to be wrong; 'semi-stainless' isn't a real designation, but D2 is usually described as such with 12% Chromium (Stainless = >13% Cr). At less than 5% Chromium, it's probably close to CPM M4. It does have relatively high levels of Molybdenum with 5.4%, and that helps with corrosion resistance, but IDK... the cladding seems like a premium feature to me, not a cost-saver.
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No more rust prone than Superblue which was offered in solid blades in both the Caly 3 and 3.5 but clad in the FRN line. My SB E4 made me realize that it is a very thin piece of SB between the clad. That and the SB clads were quite bendy compared to the more rigid SB Caly 3 and 3.5. And patina is just cool
 
twinboysdad said:
No more rust prone than Superblue which was offered in solid blades in both the Caly 3 and 3.5 but clad in the FRN line. My SB E4 made me realize that it is a very thin piece of SB between the clad. That and the SB clads were quite bendy compared to the more rigid SB Caly 3 and 3.5. And patina is just cool
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Okay, I was wondering if the patina might be a part of it. That's cool. I'm not as into it myself, but I can see the appeal. The ZDP-189 Caly 3.5 in CF also used a San Mai III construction, and the cladding seemed very thin. Almost like a sacrificial or galvanic layer, but of course, corrosion resistant in 420J2. I was confused why a steel that has 20% chromium would need it.

I assumed it was being used for the same reason Japanese swordsmiths invented the San Mai construction: to allow the ZDP core to be heated for maximum Rockwell levels of 67, which would give it superior edge retention; and wrapping this ZDP-core to provide reinforcement for the spine with a softer, more flexible steel, alleviating concerns about brittleness that a 67Rhc can raise.

I later heard a reviewer on Amazon comment that the SM3 was there to protect the ZDP from corrosion. I disagreed, mentioning that protecting a 20% Chromium stainless steel (ZDP-189) by using a 14% Chromium stainless steel (420J2) didn't make sense. I had to eat crow later when researching the issue; I found a BF thread in which Sal Glesser himself confirmed that ZDP-189 is one of their worst performers, as far as SS goes. The 3% carbon counters the resistance prov. by the Chromium.

So the fact that the clad blades of SuperBlue were more flexible is a good thing; you get toughness and flexibility where it counts - the spine - and rigidity where it counts - the cutting edge. The unclad Caly Superblues would probably have a lower Rhc than the Endura SB, slightly less edge retention, and an increased chance of breaking a tip off. Hypothetically speaking, that is. Alloys are very complicated and confounding, and the way elements react to one another is unpredictable, at least to me.
 
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Just for the sake of littering this fine thread with more graphs, here's a group photo featuring HAP 40 with friends and family... maybe distant cousins.

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It was mentioned somewhere that, like Super Blue, HAP40 will eventually make its way into the entire FRN lineup. Personally, I'm excited for a Dragonfly2, especially given the composition charts that have been posted so far.
 
Soooo... any chance this HAP40 might work it's way into a PE Lil Matriarch blade?? Surfingringo brought that up elsewhere & I'd definitely jump on that boat ride! :)
 
jpm2 said:
The closest I can find to HAP40, that I'm familiar with, is M36 & M35. This is a definite :thumbup:
I have several blades in M35.
Being a sucker for HSS, and in Delica form, I'll overlook the bright orange handle. :D
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Thanks for this chart... When I do a google search for m35 I see it is often used for circular saw blades. The impression I get is that it is similar to M2 but with additional cobalt. One of the effects of the high cobalt is to improve the red-hot hardness, which is not directly useful for knife blades, unless you take into account power sharpening at the factory.

Some more info here:
http://en.m.wikipedia.org/wiki/High-speed_steel

A few comments by Jerry Hossom here:
http://www.knifenetwork.com/forum/showthread.php?t=14281

My gut feel is that it will be very similar in performance to M4 for our uses.
 
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Brock O Lee said:
Thanks for this chart... When I do a google search for m35 I see it is often used for circular saw blades. The impression I get is that it is similar to M2 but with additional cobalt. One of the effects of the high cobalt is to improve the red-hot hardness, which is not directly useful for knife blades, unless you take into account power sharpening at the factory.
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I've read that in addition to increasing red hardness and attainable hardness, cobalt intensifies the individual effects of other elements in the steel (molybdenium, tungsten, vandium, etc). I like to think of M35, as M2 on steroids.
A few comments by Jerry Hossom here:
http://www.knifenetwork.com/forum/showthread.php?t=14281
My gut feel is that it will be very similar in performance to M4 for our uses.
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You're probably right that 99% of knife users will never know the difference, but...
On paper, M4 is supposed to outperform M2 in every way. In practice, I haven't found that to be the case. I can tell you that my M35's outperform my M2's in every way.

I'm sure the poster in that thread is refering to parting tools, the same type I ground my own blades from, both 5 and 10% cobalt ones.

Mr. Hossom is correct in his assessment of working with it. As an example, M35 is much harder to grind than M2, and M2 ain't easy. I suspect this is one reason M2 is no longer used, and no one wants to work with it.

I'm excited about a HSS-Co M35 class folder, I hope the HT is right.
 
I have some experience with m4, so I'll just have to order a Hap40 and write it down against 'education' :)
 
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I have a small petty made of HAP40. I have sharpened it only once in a year and it gets used often. With a little common sense knife care it has only discolored a bit. I will get an endura when it comes out. Russ
 
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