HAP 40 Mule Team attempt

gscreely

gscreely

Knifemaker / Craftsman / Service Provider
Joined
Jun 3, 2008
Messages
178
So I wanted to work with some HAP 40 to see what it is all about, of course as with many Hitachi steels they are just not readily available here. So I was on the hunt for an American equivalent, and what I have come up with is CPM REX 76. Very similar to HAP 40 with a bit more tungston. I am in the process of of doing a run of bird and trout sized blades that I am going to offer on the forum as a ground blank without handles. (I will also finsh some) I thought this would be a cool way to contribute to the knife community. So it is not hap 40, and not a Mule Team, but a similar idea.

PS- The heat treat will be done by Peters with Cryo.

14079772_10154423918034491_732854850402146874_n.jpg
 
Sounds like a fantastic idea. I will be watching for updates closely.
Subscribed.
 
It looks like 4 to 6 weeks out until I have the hardened steel in my hands. I think I will offer these flat or hollow ground and sharpened, or just a hardened blank. So if you just want to harden blank they will be about 4 to 6 weeks out, I would imagine in 6 to 8 weeks I could start trickling out ground blanks and a few finish knives with Kydex sheaths.
 
What hrc are you shooting for?
Do you have any experience with the alloy prior to this?
 
I do not have experience with this alloy ( in fact very few knife makers do, this is the kind of steel that they use to cut other steels in an industrial application), it is able to be hardened into the upper 60s, but I suspect I'm going to try to keep it a little lower than that. I want to find out what spydercos hap40 is at because it seems to be a good performer. If the heat treat work today And based on the conversation with my heat treater I would probably target 64Rc, but I am still in the research phase as far as that is concerned.
 
Looking forward to see how this turns out.
 
Sounds interesting/appealing.
Do you have any expectations of your BTE thickness?

Here is a quote on Spyderco Hap40 hardness.
Sal Glesser said:
The maker says the hardness is Rc 63-64.

sal
Click to expand...

That same maker runs their kitchen knives around 66-67 rc iirc.

I am not definite but I want to say I recall the first batch of Hap40 having some slight chipping issued when under 17-18 dps when pushed to more demanding work other than slicing. Though this was due to it being ran harder than their current values.
** I may be confusing this last statement with their initial run of ZDP on the stretch/endura, which was corrected and hardness lowered on the subsequent runs.

This may be worth looking into, I know I will be doing so.
 
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The BTE thickness will be about .012 and the stock is going to to be around .160 which is a little thicker than I would prefer, but this steel is not rolled in common blade thicknesses (yet).
As for the hardness, I think I am going to go for 63RC. This steel as quenched is 68RC, so coming down to 63RC actually represents a pretty significant temper. For instance S90V is 60-63RC as quenched.

This should compare very favorably to HAP40, which is to say edge retention and toughness should be of the charts. -plus it is made in the US of A.

Here is a 52100 in one of the shapes:
14068209_10154427408374491_3758116831453346863_n.jpg



Here are the 2 shapes with dimensions:
14067977_10154428286209491_5773418739141633357_o.jpg
 
Kohetsu has their 240mm Hap40 Gyuto at 65-66 hrc

That small knife would be awesome at that hardness
 
I like the bottom as it is.
The belly looks Fantastic on it, the handle looks quite ergonomic too.
Another reason why I like the second is that these are to fit whomever handles them, and the swell in the center of the palm will fit 90% of the people out there.

Just a personal thing but with th handle being 4.38" I could bring the handle down to 4" even and lengthen the blade. Though at the current length, it would keep the lanyard out from under my pinky/palm for sure.
 
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I agree with NJBill,
Not only will the knife make for a good testing platform for the steel it would be very useable.
 
LG&M said:
I agree with NJBill,
Not only will the knife make for a good testing platform for the steel it would be very useable.
Click to expand...

I have always liked smaller blades, and the steels edge retention performance is quickly exposed.
 
Well, when you only have (just under) 2 7/8" blade length, there is only so much real estate.
Works well for edc for me as well...
 
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