Hap40 vs zdp189 vs k390

[silvershade255]

I'm considering picking up an endura in hap40, but already have a police in k390 and haven't tried zdp at all.

So I ask: If you have or had both, is the endura too close to the police that you find them to essentially overlap?

And how do the steels compare in use or in theory? (Meaning in theory one steel should have higher edge retention or toughness but in practice could be indistinguishable from each other)

[Doc Dan]

ZDP is a real bear to sharpen and is not tough.it does hold a long lasting edge. K390 is not too terrible to sharpen. It is far tougher and holds an edge a long time. ZDP is supposed to be more stainless on paper, but K390 is not as bad as many non stainless steels. Of the two, I’d take K390.

[emanuel]

Get the HAP40, its tougher than ZDP by far, and since you already own a knife in K390, you won't be missing much in term of edge retention/aggression. Maybe the one thing that ZDP can have over K390 is its fine edge, but does that really matter to you? HAP40 is way more different, and its just a tad bit softer than ZDP but that translates to superior edge stability, shapenability and overall toughness.

[navin johnson]

In my experience ZDP is only a bit more time consuming to sharpen than S30V as long as the edge is not overly blunted. It machines slowly but has almost no burring. It holds its sharp edge better than S110V (S110V will hold a working edge longer). For personal carry I value a fine sharp edge.

The FFG blades are not what I would consider tough. Blade shape can mitigate some of this. A Stretch is likely much more resistant to abuse than a FFG delica or endura with their pointy tips. Don't fear ZDP.

[ZrowsN1s]

[TomAiello]

As a Police 4 owner, I basically never use my Enduras any more. I find that the (for me) the Police is pretty much better in every way.

Between ZDP and HAP 40 I'd pick ZDP, but those are both steels I use in smaller, slicing platforms. In a larger platform I might lean more toward HAP40? Not totally sure.

[marty_bill_]

I totally agree. P4 K390 all the way.

[Cycletroll]

I have a Police 4 as well as Enduras in both Hap40 and ZDP. Each has its own personality. The P4 is a cutting machine and surprisingly svelte for how big it is. Nonetheless, it is a huge blade and is more of shock to sheeple than even an Endura. My HAP40 Endura sports custom G10 scales which give it a much more hand filling comfort which suits its tough nature. Seems to me that the hap40 and K390 are very similar with perhaps a touch more edge aggression in the K390. The ZDP Endura is one of my all time favorites. Great slicer in a slim light package. Stainless enough for anything less than silly and holds an edge for a long time! Ive not found any issues with edge damage but I don't chop with it nor do I pry. It is a slicing tool. If i had to pick just one would probably be the lovely green zdp Endura.

[Cambertree]

They’re all excellent steels in my experience.

In fact my main ‘work knives’ are in those three steels.

HAP40 will give you a bit more toughness and sharpenability, though K390 has been fine in both those regards too, for me.

I’d try ZDP189 if you haven’t had a knife in that steel, as it gives the added benefit of stainlessness - although it’s on the lower end of corrosion resistance among the stainless steels.

I once had my ZDP189 Dragonfly clipped IWB on my shorts while mountain bike riding in hot weather all day. At the end of the day, the blade had an orange layer of oxide all over it, which wiped off without leaving any visible pitting.

Apart from that I haven’t had any issues with rust, although I select my steels according to the needs of the task and environment.

If you’re used to maintaining tool steels like K390 it’ll be no problem.

I personally haven’t had problems with sharpening ZDP189, just approach it with patience, knowing it’ll take a bit more time than some other steels.

I run it with a 10-12 dps back bevel, and a small 15dps Sharpmaker apex bevel, finishing with a few passes on the UF rods at 20dps. Makes it very easy to resharpen, or change the edge apex from polished to coarse with a few strokes.

I don’t really use my Enduras much any more - I prefer the comfort of the Police 4 handle. But the P4 is still a bit much to whip out in every kind of social setting.

[jpm2]

Got all those steels in multiple blades and rate them in order like this.
edge wear - k390, zdp, hap40 (coarse or fine)
strength - zdp, k390, hap40 (hap40 rolls edge easiest)
toughness - hap40, k390, zdp (zdp cracks edge easiest)
overall edge stability - k390, hap40, zdp (zdp gets damaged easiest )
Ease of grinding - hap40, zdp, k390 (k390 hardest to reprofile)
Ease of sharpening, zdp, k390, hap40 (hap40 burrs the easiest)
Overall, I prefer k390, hap40, zdp

[Doeswhateveraspidercan]

Prefer HAP40 have pocketed it in Florida heat drenched in sweat using it hard and dirty no rust at the end of the day.

K390 rusts very easily but can be flitzed clean easily enough.

ZDP have it used it a bit not one of my favorites when it comes to steel.

What you really need to ask yourself is what you want in a steel?

For example I prefer CRUWEAR & VG-10 and HAP40 because of the following characteristics.

#1. Sharpening response
#2. Holds a truly sharp Edge for a long period of time
#3. Easy to bring back to a truly sharp edge
#4. Corrosion resistance way above what the paperwork presents.

Others prefer a long lived working edge and go high carbide.

Personally I often wonder when the high carbide fad will die off?

[jpm2]

...
For example I prefer CRUWEAR & VG-10 and HAP40 because of the following characteristics.

#2. Holds a truly sharp Edge for a long period of time

Others prefer a long lived working edge and go high carbide.

Personally I often wonder when the high carbide fad will die off?

Personally I hope it never dies, that would be going backwards with edge retention and stability.
I think a lot of people struggle with high carbide steels, they are not as easy to get a durable fine edge as lower/no carbide stuff. Proper technique and abrasives are key.
In my experience and generally speaking, the higher the carbide content, the longer the fine edge retention (and working edge retention).
Not sure what's considered "high carbide" but hap40 has a good bit of carbide formers with 1.3% C, 4% CR, 5% Mo, 3% V, and 6% W. It just ended up being ran a little softer than what we see most high speed tool steels run at.

[Doeswhateveraspidercan]

Yes HAP40 does almost kept me from buying it. Running it softer makes sense it does sharpen very easily. Thanks.

[kwakster]

HAP40 needs to be around 65-66 HRC to really shine.

[Cambertree]

HAP40 needs to be around 65-66 HRC to really shine.

Yes I’ve been tempted to try a kitchen knife in HAP40 after reading your posts on another forum on the Kohetsu, was it?

The Rex 45 run sounds very impressive, and I don’t disagree that HAP40 would be great at 65-66.

But after using the Seki HAP40 sprints at around 62-64 HRc or thereabouts, quite extensively, I still like the balance of toughness and edgeholding and sharpenability.

I think I recall you mentioning that the HAP40 chef knives you had, chipped a bit, when used on hard, crusty loaves of bread (as many high hardness knives will).

I prefer working pocket knives that roll rather than chip, when pushed past their limits, and I never worry about the Seki HAP40 knives I have (Endura, Stretch, Delica Wharny, Dragonfly and Manbug) chipping in use.

[kwakster]

Yes, my posts on the other forums were about HAP40 Kohetsu santoku's @ 65 HRC.
The minor chipping one of the Chefs experienced was with an edge angle of ~20 degrees inclusive, and indeed while trying to cut the rock hard crusts on a few artisan breads, which i consider abuse.

Although i certainly agree with your statement on rolling versus chipping for working pocket knives, my educated guess would be that at a more common ~30 degrees inclusive edge angle (for pocket knives) the chances of chipping would greatly diminish.
Even at ~65 HRC HAP40 can be considered quite tough, noticably tougher than ZDP-189 at the same hardness.
And also noticeably more corrosion resistant, as in pro-kitchen use it only seems to form a patina.

REX45 also has my interest, especially if it's real life properties are like HAP40 and is run at a comparable hardness.
So far Kohetsu's HAP40 @ 65 HRC is my current king of the hill regarding taking & holding highly polished edges (up to 1.0 micron diamond compound) at low edge angles (apex @ ~20 degrees inclusive)

[Cambertree]

Thanks for those further observations Kwakster.

I think it was the hope of quite a few forum members that we might get a non-laminated HAP40 blade run at a higher hardness.

Big Brown Bear's tests with REX45 run at around 65-66 HRc did indeed show it seemed to be quite tough, slicing and torquing into brass rod.

That's also very interesting what you say about HAP40 only patinaing in extended pro kitchen use.

Ach, I don't want to start buying high end chef knives again though - I've enough trouble trying to rein in my folding knife spending!

Have you tried K390 yet? I have found it to be very impressve blade steel. Not as corrosion resistant as HAP40, but also takes a very fine edge, and holds it outstandingly well, while still being surprisingly tough in thin cross sections.

[GarageBoy]

Curious - how low of an angle will these 3 steels hold and not chip out for normal edc tasks (reliably) ?

[Cambertree]

Curious - how low of an angle will these 3 steels hold and not chip out for normal edc tasks (reliably) ?

It really depends on what 'normal use' is for that individual user. For example, cutting through cardboard really fast will increase impact damage from hard particle inclusions, compared to slicing it slowly. Slamming a knife into a bamboo chopping board repeatedly while slicing vegies will be harder on the edge than cutting the same material smoothly on an end grain board.

So I don't really like to give prescriptive angles and thicknesses. The way to find what the thinnest, most acute edge is for you, is just to keep thinning it out until it starts to fail by chipping or rolling in normal use, then gradually increase your angle little by little until it stabilises for you.

There you will have your individually customised 'lowest edge angle'.

Having said that, some of my Japanese chef knives are around 0.006" behind the edge, and sharpened at around 8 degrees per side. That's VG10 and White Paper No.1 steel, but HAP40 can no doubt handle the same. ZDP189 is also commonly used in Japanese chef knives, so it can probably take a similar angle and thickness, although I've never personally examined a chef knife in either steel.

When K390 was first released, I remember someone asking the Bohler metallurgists whether it would be able to be used to make custom straight razors. I was a bit dubious, considering the carbide volume, but they seemed to think it would perform very well in a straight razor.

Straight razors tend to be around 16 degrees inclusive.

Those kind of edges are obviously not really suited for most 'utility use'.

[kwakster]

Have you tried K390 yet? I have found it to be very impressve blade steel. Not as corrosion resistant as HAP40, but also takes a very fine edge, and holds it outstandingly well, while still being surprisingly tough in thin cross sections.

Although i still haven't tried them, some time ago i bought both a K390 gyuto @ 64 HRC as well as the exact same model in Elmax @ 62 HRC from the Sabol Brothers, up-and-coming custom knife makers based in Slovakia, Europe.
Their Chef knives are already sold through Chefknivestogo in the US.

https://www.bladeforums.com/threads/sab ... t-18917653

The brothers think that their K390 blades should be able to match and maybe even surpass the Kohetsu HAP40 blades regarding taking & holding finely polished edges at low edge angles, while i think that the stainless Elmax blade might do well in comparison to the also stainless Japanese made R2/SG2 blades which many Dutch pro-Chefs here like.
The current plan is to lend my K390 gyuto to a professional Chef-de-Partie i know to see what he thinks of it.
This guys workday consists of cutting vegetables & meat for 4-5 hours per workday, and he's real good at what he does.
His current workhorse is a Takamura R2 gyuto that i've recently hand reground the blade into full convex zero edge @ 22 degrees inclusive for him.