H1 Steel for Dummies

The Government

The Government

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Aug 21, 2009
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I would like to hear about some of the unique characteristics of H1 steel -and please if possible, in layman's terms.:o

All I know is that it is created much differently than other steels. So what makes it different?

It has nitrogen instead of carbon -how?

*It cannot have a full flat grind -why? (*This is my primary question)

Those are my main questions -if there is anything else unique and interesting about this steel I would be very happy to learn about it.

Thanks for helping out!

The Gov:)


BTW- I have a Salt 1 and love it. I have been using it for a while in the Pacific O and it is impressive.
 
I can't answer the 'how' questions, but from what I've heard:
Spyderco does hollow grind only on H1 blades, because of the wear on the grinding machinery. The H1 work hardens (becomes harder as it's ground), that's apparently the issue. Therefore, no full flat/scandi/convex grinds. This is apparently not a 'can not', it's a 'don't, because it would be expensive'.

Here are other facts I find cool: Work hardening gives H1 blades a differential temper, just like many 'samurai sword' type blades; H1 tends to be very tough stuff - I think Sal posted somewhere an invitation for folks to send in their blades from other companies (Busse, Strider, CR...) and he'd be glad to do a side-by-side destructive test, since he has the gear :); the differential temper has a higher RC at the edge on serrated blades; the stuff is completely rust proof under normal circumstance (someone was able to get an H1 knife to degrade when subjected to something like pure chlorine); some of us think it's the neatest thing since sliced bread (me, for example), others are not so impressed.

Maybe someone will chime in on the 'how' questions.
 
Thanks,

I am one of the people who thinks H1 is the neatest thing since sliced bread:thumbup:

That is why I need to learn the basics. :)
 
The shot show vid that was in a thread here not to long ago had some good info on H1. From what I gathered the steel has NO heat treat but instead is compressed, to get a 4mm blade they start with 8mm of steel. I too have no idea why it can only be hollow ground but it would be intresting to know.
 
knifenut1013 said:
The shot show vid that was in a thread here not to long ago had some good info on H1. From what I gathered the steel has NO heat treat but instead is compressed, to get a 4mm blade they start with 8mm of steel. I too have no idea why it can only be hollow ground but it would be intresting to know.
Click to expand...

Compressed? Interesting. Do you have a link to this video?

The reason it "can't" be flat ground is that because flat grinding is done one side at a time. When you grind H1 it work hardens so after you've done one side it's harder to do the other side. Hollow grinding does both sides at the same time so it avoids this.
 
As far as I know it must be grinded on both sides at the same time based on the work hardening propreties, and this would halt ffg blades in terms of mass production based on cost and technological requirements.

Epic grind monkeys like Krein can do it but its by hand, piece by piece.

H1 bends rather than snap like alot of carbon steels except that unlike carbon steels its impervious to rust and this makes it truly unique and awesome.

It keeps a pretty good edge for a reasonable amount of time and I think alot of folks like the low maintenance, easy to sharpen aspects of this steel.
 
This "work hardening" characteristic is very interesting.

I am curious how significant the cost would actually be to FFG it. I would pay a premium for a Mariner salt with a plane edge, salt 1 shaped blade, and a FFG. Or better yet a FFG fixed blade in H1.
 
Josh, it was the Nutnfancy vid of shot 2010
 
The Government said:
This "work hardening" characteristic is very interesting.

I am curious how significant the cost would actually be to FFG it. I would pay a premium for a Mariner salt with a plane edge, salt 1 shaped blade, and a FFG. Or better yet a FFG fixed blade in H1.
Click to expand...

As has been mentioned, the FFG can be done by hand and Tom Krein just recently did a Rock Salt for a Spyderco Forum member. It turned out awesome! So, if you really want it done, buy the knife and send it to Tom for it's makeover.:thumbup:
 
I'm thinking about buying a Rock Salt, but don't want one if H1 is a dog of a steel as far as sharpness and edge holding goes, the no rust factor is not that important to me........how does it compare to say, VG-10 in this area?
 
Gatogordo said:
I'm thinking about buying a Rock Salt, but don't want one if H1 is a dog of a steel as far as sharpness and edge holding goes, the no rust factor is not that important to me........how does it compare to say, VG-10 in this area?
Click to expand...

Edge holding is comparable to AUS-8, which is a couple of steps below VG-10. Sharpening is also about the same as AUS-8.
 
Josh K said:
Edge holding is comparable to AUS-8, which is a couple of steps below VG-10. Sharpening is also about the same as AUS-8.
Click to expand...

Gradually improving the more you use and sharpen it in my experience.
 
Naga99 said:
Here are other facts I find cool: Work hardening gives H1 blades a differential temper, just like many 'samurai sword' type blades;
Click to expand...

Wouldn't you lose some of this property if they indeed did offer a FFG?

I guess you would still have some of the differential "heat treat" effect because more material will have been removed at the edge than at the spine but it seems to me that you would lose at least a little of the flexibility by doing a full flat.
 
H-1 cannot be flat ground at the factory because it warps when ground at factory speeds. Grinding both sides simultaneously negates the warping. Hollow grinding is much cheaper as well.

To work harden the steel they cold roll it (run the steel through big rollers under tons of pressure). All steel must be rolled at the foundry to refine the grain structure, normally they do it with the steel still hot to make things easier.
 
If they could figure a way to press blades we would be set, you could have any blade shape or grind style you wanted.
 
Josh K said:
Compressed? Interesting.
Click to expand...

This is WAY outside of my expertise, but as I understand things, it is not compressed (since it is solid), but it is pressed and rolled in a compressive manner to cold work the product. This cold working hardens it.

Somewhere I saw hardness numbers posted for raw H-1 stock, then again for cold worked H-1, but I can not recall where or what the numbers were exactly, but the increase in hardness was considerable.

Typically they will start with stock that is wide and roll it out similar to rolling dough into thinner sheets from which you cut cookies (or in this case knives..and with much higher applied stresses).

The material continues to harden as it is worked (sharpening etc), but this is a smaller (but still significant) increase in hardness compared to the heavy cold working.

Full disclosure: all this is stuff I have learned researching H1 on line, so treat my words like anything else you read on line!
 
If it is work/sharpening hardening, how hard can it get in normal use?
Just a bit harder, lot harder, or can it be overworked and overhardened in use?
 
idaho said:
If it is work/sharpening hardening, how hard can it get in normal use?
Just a bit harder, lot harder, or can it be overworked and overhardened in use?
Click to expand...

It can harden to the point of being chippy, and if it does chip you are back to a less work hardened surface and the circle of life starts all over again ;)
 
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