Has Anyone Ever Broken Off A HAP-40 Blade ?

[Wowbagger]

I hesitate to post this here because I want as much exposure to the question for as much input as possible. I post it here in the Maintenance Tinkering and Embellishment forum because I don't want to start a panic that there is anything wrong with HAP-40 (there isn't it is just great) and I want to talk to Gear Heads and Metal Heads (those are respectful and endearing terms / not derogatory) rather than talk to all the "Well why do you want to snap off your blade for ?" types.

I ask this because I just bought a Delica with HAP-40 and plan on cutting and reshaping the blade to a more traditional light duty blade shape such as my Ti Lite IV shown at this LINK > > > third photo down.
Why : so it can cut curves better. A narrower blade cuts curves better than a wide blade.

The jury is still out on whether I keep the full spyder hole or cut it back into a very tame wave hook. I don't need much of the hole to open the knife with my thumb so I will still keep enough of the hole to thumb flick it open.

Don't tell me I'm crazy (there have been many before you) just tell me how strong / weak you have FOUND . . . CLADDED . . . HAP-40 to be.
Please

 

[kwackster]

Well, i have no experience with Spyderco models in cladded HAP40 steel, only with sharpening/polishing several Japanese Kohetsu santoku's & gyuto's in cladded HAP40 @ 65 HRC for both a few demanding amateur and pro-Chefs, and based on feedback those knives are actually my current king of the hill regarding taking and holding highly polished edges (up to 1.0 micron diamond compound), maybe even a bit better than ZDP-189, but much less sensitive to edge corrosion, as well as seemingly tougher overall.
Chipping doesn't seem to happen easily for such hard knives, and when they do those chips tend to be noticeably smaller compared to ZDP-189 steel of the same hardness.

Started this picture thread some time ago about a few of those Kohetsu HAP40 santoku's here:
https://www.bladeforums.com/threads/kohetsu-hap40-santoku.1509214/

 

[Wowbagger]

Kohetsu santoku's & gyuto's in cladded HAP40 @ 65 HRC . . .

Started this picture thread

Blade thickness: max 2.06 mm
Steel: Laminated HAP40
Hardness: 65 HRC
Blade: double sided convex grind with half-sided convex bevel and a narrow V-bevel on top which forms the actual edge.
Edge angle: between 17,5 and 20 degrees inclusive (measured with Tormek WM200 Angle Master)

I think I'm in love . . .
no . . . I'm definitely IN LOVE !

Chipping doesn't seem to happen easily

I know. I trimmed some strips off some sort of hardish plastic trays the other day at work and then stopped my self (what the hell am I doing; I'm bound to chip this hard edge).
Then the same day I found myself having to cut some seemingly abrasive cord. Stuff the owner keeps around to get rid of in place of string, on a huge life time supply spool . . . I've heard it is trip wire line or some such, it's black and feels like sand paper.

I decided to use the area of the blade right near the plunge grind so I wouldn't have a dull area out on the belly.

Once I got home and on the couch I pulled out the Delica and reluctantly checked the edge :
Zero problems, the entire edge as sharp as it came from Seki City which is just fantastically hair splitting sharp. Fantastic for a mass produced knife edge.

 

[kwackster]

Is the hardness of Spyderco's HAP40 known ?

 

[bikerector]

I think you should be fine to mod it, if that's what you're asking. As far as durability of the steel, I'm really not sure as I've only seen it or used it on folders and they aren't going to see the type of use that a fixed blade would. For carving, where you're putting some side load on the edge, I can't help you on that one. My experience with it is limited to the endura from cutlery shoppe. My understanding is that it most closely resembles M4 in use, though the chemistry is still pretty different.

Here's what cutlery shoppe says (probably straight from spyderco).

More about HAP40 Blade Steel:
HAP40 is a powder metallurgy high-speed tool steel made by Hitachi Metals Ltd. of Japan. It is well known in Japan and used in high end cutlery, due to its excellent balance of hardness, toughness and edge retention.

From spyderco's description of the HAP40 delica (bolded what I think you're looking for):
This limited-edition Sprint Run combines the proven features and benefits of the popular Delica 4 Lightweight with a laminated blade crafted from HAP40 and SUS410 steels. The center layer of the full-flat-ground blade is made from HAP40—an advanced high-speed tool steel produced by the powder metallurgy process. HAP40’s generous amounts of tungsten, molybdenum, vanadium, and cobalt give it exceptional toughness and high abrasion resistance, both ideal properties in a high-performance blade steel. The HAP40 core is sandwiched between layers of SUS410—a martensitic stainless steel that provide increased strength and improved corrosion resistance.

 

[jpm2]

Never broke, cracked, or chipped Spyderco hap40, can't say the same for a lot of other steels.
I say go for it. Here's one I'm working on.

 

[Wowbagger]

I think you should be fine to mod it, if that's what you're asking.

That's it in a nut shell.

made by Hitachi Metals Ltd. of Japan.

That gives me confidence right there. I like their blade steels

toughness and edge retention.
. . . exceptional toughness . . . sandwiched between layers of SUS410. . . that provide increased strength

That is what I am hoping. The layers will be pretty thin when I cut a fair amount off the top / spine area. I will obviously be easy on it but it will take some torquing loads while cutting curves. Most likely for card stock for quick signs or corrugated cardboard for packing material, leather work and I don't know what else. I just want this knife and I will see what all I use it for once I get it.

I'll need to pay particular attention to any line or notch that looks like a stress riser and blend those areas to spread out the stresses.

Thanks for the confidence building encouragement guys.

 

[Wowbagger]

Is the hardness of Spyderco's HAP40 known ?

I don't know. I'm hoping at least 63 or 64
Ankerson doesn't seem to be sure he posted this in his tests and he likes to post the hardness if he can.

HAP-40 - 320 - Spyderco Endura - ? RC - .024" behind the edge

. . . by the way by the 320 cuts that I first saw in the tests I blew off HAP-40 when it hit the scene as being just another flash in the pan steel.

The rope cutting FOR ME doesn't tell the whole story buy a lory load.
My very fav steel is way down the list (M4 at a measly 500 cuts) and HAP-40 is in the gutter with 320 cuts.

Turns out these are my top two very favorite steel alloys for my work knives. I have many knives with the more superer super steels that are way up there on the rope cutting list and . . .
you can have them; they just don't do it for me . . . give me the M4 and HAP-40 for my work any day !

and it isn't that the other stuff is too difficult to sharpen. The Edge Pro with the diamonds gets EVERYTHING just silly, silly sharp and quick like a bunny.

 

[Wowbagger]

A quick update for anyone who cares (or wants a quick laugh) . . . (or wants a seriously over the top slicy little knife).
I did it. For good or bad.
First I put the HAP-40 blade in my black FRN Delica Wharncliffe handle. Turns out Delicas aren't that hard to rebuild see my post in the Nick Shabazz thread HERE AT THIS LINK > > >.

Then I blued the blade with dye, scribed a line 13mm from the edge all the way back to the bottom of the Spyder hole. Clamped a soaking wet sock to surround the edge of the blade to prevent heat getting to the edge. Took my Dremel with an abrasive cut off disc and in short bursts followed by drenching the blade in more water for cooling I slit the blade along the line and at the spine at the top of the Syder hole.

I rounded the spine on my cool running Norton X grinder wheel and cleaned off the dye.

OOOOOoooooh MAN . . . . what have I donnnnnne ?
This thing looks frail !

Whipping out the Mitutoyo Calipers I measured the thickness at the spine . . .
. . . wheeooh that's plenty . . . a FULL 1.3mm
In comparison my modded Ti Lite IV is 1.9mm at the spine and it is about twice as long.

Nooooooo problem (I hope ) (. . . to quote Hunter S. Thompson : Oh GodOhGodOhGodOhGod).

The freakin' wave/hook I left on there is way too grabby on my pocket. Even curling a finger around the tip of the blade or otherwise trying to take the knife out of my pocket without it hooking inside the pocket in my pleated baggy shorts was just too iffy. It might be OK with jeans. If I cut more off the hook I will be cutting into the jimpping so for now I have removed the pocket clip and will carry the knife in the bottom of my pocket or in a belt pouch.

Turns out that is pretty cool because it is super easy to just take the knife out of my pocket OR hook it on my pocket-opening to wave it.

The knife is light enough that I won't notice it just loose in pocket.
(lighter now that HALF the blade is gone ! ! !) (Oh GodOhGodOhGodOhGod WHAT have I done . . .)
It'll be OK, It'll be OK, It'll be OK

More later.

 

[Wowbagger]

PS: there is still enough blade above the handle when closed that I can pinch it open (I could put in a nail nick but won't) so even if I took the wave/Spyder hole off completely the knife would still be usable, but not one hand openable by pinching.

 

[Wowbagger]

The freakin' wave/hook I left on there is way too grabby on my pocket.

I cut some more off the hook; I took all of the metal off right into the jimping (before I had like 2.5 to 3mm before the jimping.
This makes it way less grabby on my pocket lining (I'm carrying it loose in pocket with the clip removed).
I think it is perfect now.
I can still easily thumb open it; still plenty of Spyder hole remaining for that.
I can easily wave it open on my pocket but it doesn't catch annoyingly like before.

Having the clip removed is interesting because much more of the FRN is exposed and usable.
This is useful when I flip the knife over edge up. I was cutting cardboard today to shape the pieces and it was best to cut it with the point pointing at the ceiling and the edge facing me. I know this can be dangerous; think holding the knife and pulling the cardboard past the blade with knife arm not traveling. It isn't as dangerous as it sounds. Short cuts less than two feet long. Works for me.

Glad I made the mod.
CAUTION : anyone taking this much off the blade needs to be careful not to break the blade. I think I should be fine for the use I will put the knife to. Light work.

 

[Rykjeklut]

This thread desperately needs some pictures.
I'm not sure if I can actually visualise what you've done.

 

[Wowbagger]

This thread desperately needs some pictures.
I'm not sure if I can actually visualise what you've done.

You couldn't be more right.
I can't post photos right now for a couple of reasons.

Here is a photo off the web that is pretty close.
Full flat grind it, take the wave (pocket hook) all the way back into the Spyder hole with the hook pointing up more rather than toward the blade point, and make the spine at the bottom of the Spyder hole and or a little above where the saber grind turns to the primary bevel in this photo and you got it.
All the blade where the Spyder is in this photo is gone except for the hook but like I said the hook is only way back nearer the pivot formed by the rear of the Spyder hole.
Oh and mine is a Wharncliffe so no blade belly.

PS : it started out looking like this Wharncliffe below

 

[Wowbagger]

It sounds to some, and looks to me, to be frail.
However I was just using this Case Teardrop Wharncliffe and its blade is considerably less wide than my HAP-40 Delica so maybe it'll be OK.
Dang this Treardrop performed very well at breaking down some cracker boxes.
A very enjoyable blade style for me.
Imagine the blade below with a wave hook on it and that's about what I did to the Delica.

 

[Wowbagger]

This thread desperately needs some pictures.
I'm not sure if I can actually visualize what you've done.

Pictures the man says. Actual pictures not pirated pictures is what you want I suppose.
Pictures you want and pictures you will have :




That's a quarter next to the blade. The spine of the blade is rounded so it looks even thinner than it is.
Frightening isn't it ? !


I carried it with the clip on for a while. I thought I had gotten accustomed to holding it right when I didn't want the wave to hook on my pocket . . . until a few days ago when I was in a hurry, pulled the knife out of my pocket to put it in my back pocket (into the bottom of my pocket) and the blade opened partially and then closed on the back of my finger. No real damage done but it was drippy. All when I am in a rush to get out the door and on my bike to ride to work. All I can say is carry some wide bandage tape, stuff some kleenex in the hollow in the roll as I do (all clean in a zip lock) . . . AND FOR THE LOVE OF BOB DON'T PUT A CLIP ON THIS FRANKEN KNIFE IF YOU EMULATE MY MADNESS.

I removed the clip again. It works very well just carried loose in my pocket and I can decide as I draw it whether to hook the wave or not. The spring force of this lock back is quite strong so I don't see it opening on me in the bottom of my pocket. To be totally safe just carry it in a belt pouch which I have done the last two days partly because the wave jimping seems to have the potential to chew on my pocket and I just replaced my work pants where my Gerber Artifact had chewed up my pockets.

The knife is boring or disturbing to look at but I am so pleased with it's performance !
More compact now by quite a lot as well.