Edgeholding with a differentially tempered blade

tallwingedgoat

tallwingedgoat

Joined
Jan 13, 1999
Messages
1,422
Like most folks here, I started out with factory knives. And over the years, go to feel I know the territory. Especially on edgeholding. If the question was, which steel hold an edge better, 440A or ATS-34. I can easily answer that one.

But when I placed an order for a custom knife, the rules changed. My custom knife will have a soft spine and hard edge. So, which would hold an edge better, 5160 at 59-60 RC or 1095 at 56-57 RC?
 
1095 is higher in carbon and should be finer grained, so should take and hold a better edge. Hardness is not everything, the process that the blade goes through to arrive at a particular hardness has a lot to do with how tough and wear resistant it is at that hardness. And, of course, what you cut with it can be a determining factor also.

59-60 sounds pretty hard for 5160. Anybody had any experience with 5160 at that hardness?

Harv
 
In my experience those two steels, as well as a number of other wonderfully simple steels, are quite similar.

I think I get a bit better edge holding ability out of the one with more carbon (after all, steel is [by definition} iron and carbon])-- #1095, but it's really a crap shoot, and I may be simply fulfilling my own predilections.

They are both grand steels and both have a lot of history supporting their use. I suggest you make your choice on some other basis -- like the design of the knife, OR the ability of the maker to do proper heat treating of the steel (much more important than what the actual steel is).

Welcome to the wonderful world of custom knives.

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Regards,
Desert Rat

 
I think it depends mostly on the quality of the heat treat. Both steels will take and hold an edge very well if done right. Marcus
 
Are we talking forged blades or stock removal
on these or slight forging on the edge of a
flat piece of high carbon? There are different alloys and depending on hardening
and tempering will make a difference.
If done right 5160 is hard to beat for
toughness and edge holding between the two.
IMO and experience.
goshawk

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http://www.imt.net/~goshawk The race is not always to the swift, but he who hangs loose.
Don't walk in tradition just because it feels good!!!!!

 
Tallwingedgoat, I would discuss the matter with the maker in detail. He should be able to decide which steel would work best for what you intend to do. If he can't I would not want him to make the knife.

Edge holding is not a clear win for either of those two steels. It depends on what grit you are going to have the edge left at and what kind of materials you are going to be cutting. Those RC's look odd though, they would seem more sensible swapped.

-Cliff
 
Cliff: I dunno about the maker doing the steel picking. I think the maker should give a few examples of steels that would work good, thier pro's and con's then let the customer pick from thier. Because the maker will only know what will happen to the knife once it leaves the shop, while the customer will be the one useing his knife for a long long time.

As for the question at hand, I myself would go for 5160 due to its better toughness.

Sincerely,
Adam

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Self improvement is a hobby of mine :).

 
Adamantium: you picked 5160 because of its better toughness, but that doesn't help the original questioner much, since we have no idea what his application is or what he values. ACtually, we can infer it's edge holding he's after, not toughness, since that's the focus of his question. One question: are you sure 5160 at 60Rc is tougher than 1095 at 56 Rc? That goes into the "hard to believe" bin for me. Don't make the mistake of thinking X steel is always tougher than Y steel. Maybe true at the same hardness, but if you leave Y soft and bring X to its hardness limits, the reverse may be true.

Anyway, I agree that this is a decision that should be made with the maker. Not that the maker should have the final say, but it should be discussed with him. Many makers heat one steel or another particularly well (or particularly badly), and so FOR THEM, a non-obvious steel might make more sense. Tell the maker what you're doing with the knife and what you value in steel properties, and let him tell you how he can best get there.

If you're especially valuing edge holding, my answer to this question would be: neither. Get the maker to harden the 1095 above 56 Rc, that'll do it for you!

Joe

 
Joe: Woops, my bad. I read the original post wrong. I thought he was asking about bothe edge-holding and toughness.

Anyway, having re-read the post, I'd still got with the 5160 at Rc 59-60. I don't quite think that it is at its "Hardness limit". But its sure a heck of alot closer than the 1095 is.

I'm a little curiuos about how tough 5160 is at a high hardness. I've got a knife up in my bedroom that I made, Its in 5160, and the Rc is 58-59(Which is pretty darn close to the hardness in question). I'll go out and test it for an hour. I'll post the results later tonight.

Sincerely,
Adam

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Self improvement is a hobby of mine :).

 
Adam --

I've never heard of anyone taking 5160 past 59-60 Rc. That doesn't mean it doesn't happen, of course, and I'd like to hear about it if I'm wrong. But from what I've seen, 59-60 brings 5160 to its practical hardness limits. I'm sure it's still plenty tough at that range, but 1095 at 56 is pretty damn tough too!

My guess -- and that's all it is -- is that hard 5160 will hold an edge better than soft 1095. But hard 1095 will hold an edge better than hard 5160.

Joe
 
(Joe: Yout probably right about what your saying, but it's summer, I'm bored. And for the last while I've been doing yard work for my mom. It was time for me to have some fun so I did the test anyway.)

Well guys, I'm back. Did a small amount of testing on my knife. I did some cardboard cutting, and then abused my knife for a bit.

The first thing I did was put a new edge on my knife(Its name is Chubby), and on one of my knives that is made of 1095(ontario Air force survival). And I cut up some card board boxes into equal portains. Then I did push cuts through the cardboard useing the exact same part of the blade, etc... All of the standard testing procedure. The cardboard was cut up into peices 20 inches long. And I did push cuts through them until I noticed the cutting to get slightly harder. Chubby(5160) did 12 puch cuts, the ontario did 13. Now neither of these blades was by any means dull, they just weren't hair popping sharp. But the thing is, they did pretty much the exact same edge holding wise. Chubby went through about 240 inches, while the ontario went through about 260. So they are pretty much in the same ball park(Just one note, I had my 5160 knife heat treated by Rob Simonich, so the better heat treat might be the reason why these 2 preformed so similar).

After that I went on to test the tip strength of Chubby. The first thing I did was Take a piece of wood i had in my garage(It was ceader) and slam the tip into it as hard as I could, then I would bend the knife so that the handle would touch the wood. Every single time the wood by the tip would chip out. After about 20 of these the tip was still good as new. Then I desided to drop the knife tip first on the my garage floor. It is made of Cement, so its pretty hard. I worked my way up from a 2 foot drop to a roughly an 8 foot drop. I did the tip drop thing about 15 times. It just took peices ot of the floor. No tip damage was taken. Then I took a 1/4 thick piece of 01 barstock(Anealled) and rammed the tip into it. I did it hard enough each time to be able to lift up the steel with the tip everytime. Now after about 20 of these, the tip was a quite a bit duller than it was when it started out, but not a problem. It doesn't look hard at all to make sharp again.

I would of done the test where you flex the knife in a vise, but I don't have a heavy vise to do that. The only one I've got is a light duty one.
frown.gif


And my last(And by far coolest looking
biggrin.gif
) test way to just throw the knife as hard as I could, tip first into the cement floor. I only did this a 3 or 4 times, but it was really cool looking, because every time I got sparks when the tip hit the floor. I was also smart enough to do this off in my corner of the garage, when no one would care if we had a few big chips.

Anyway, i though that the 5160 held up well for the testing I did on it. I'm sure I could of done alot more extreme testing, but I don't really want to break my knife.

Sincerely,
Adam

PS: Just one more note. I now hate AOL. It was logged me off 4 times for some reason or another while I was typing up my post.

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Self improvement is a hobby of mine :).

 
Wow, thanks for the responces. To answer some questions you guys brought up, the blade is only at 59-60 on the edge. The body, spine, tang are at 45-48. Hence the unusually hard edge on a 5160 steel blade.

And yes, it is stock removal. Although all this time I've never been convinced of the virtues of forging. The steel from the factory is pretty good quality. So why would it matter how it's made into shape?
 
I think this comes pretty much down to splitting hairs,(no not the Joe Talmadge way!
wink.gif
) the other way. Both steels are great for hard working knives that have to keep a good edge. Most of my personal experience is with 5160 since that`s what I make most of my knives out of. I did some pretty exhaustive cutting tests with a thick 5160 convex ground drop point utility I made. I did the selective heat treat and tempering myself so I`m purely guessing that the hardness was in the 57-60 range. I sliced enough thick cardboard into strips to fill I large garbage can to the top and it would still shave hair off my arm. It wasn`t popping sharp but it wasn`t scraping either. I chopped a large tree branch into several pieces and shaved part of it down into a walking stick,carved the bark off and it still shaved,barely but it still did it. I can`t imagine needing better edge holding than that for any practical purpose. A few swipes with an EzLap rod and it was razor sharp again. Boy that was a sweet knife ,I shouldn`t have sold that one! D`oh.
wink.gif
Marcus
 
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