concerning damascus...

Originally posted by Kevin R. Cashen
But it should be said that similar results could occurr whenever one carefully chooses his steel to mix and follows the simple rule- "don't use anything in your damascus, that you wouldn't make a knife out of all by itself"

Pick a steel that really cuts well, and pick another steel that is pretty tough and cuts well and you should have a blade that is fairly tough and cuts well. ;)
Click to expand...

to make the very best cutting knife and with not so much concern with pretty, 10/4
and peddle to the medal Kevin.. :)
with one concern,,, with big knives, if it were my words, I would
pertain it to the edge and adjust the spine mixture to the intent of use. just my Opinion. :)
keeping in mind I know your stand on small blades versus big blades.
a 1018 core that does not extend to the edge could be a case and point.
(not limited to 1018 of course) I could go on with the same done to Damascus but in reverse
a core of the best steel extending to the edge and the rest in what you please to look at
of course again this is and has been done for years. I'm bringing this up for the new school
I hope I'm not stepping out of bounds Kevin.:confused: :)
 
I am not sure where the bounds are myself so I doubt you can step out of them. ;) But I wouldn't change a thing for the larger blades either. Perhaps a little more L6, but L6 cuts fine also. I just had this same discussion on another forum. That is, whether softer materials are what a person wants if they are going for a big blade.

If no one minds I am feeling lazy after an afternoon of wood cutting so I will just cut and paste from my conversation about this on Swordforum:

“I am glad the blade is back in the configuration that you want, but your friend is a thoughtless fool. You may be relieved to have the blade straight again but your friend is not off the hook. The fact that you had a set after the load was removed shows that the yield point for the steel was exceeded, what this means is that even though it is straight again it will never be the same as it was before the bend.

Anything less than the yield point is elastic strain and this is reversible upon removal of the load (well mostly), anything beyond this induces plastic and permanent strain. In simple terms your blade has stresses in it that were not there before and if they are localized in one area that area could be a weak spot that can only be entirely erased by heating to a recovery temperature (an entire reheat treat).

You may never notice the difference, you most likely will not, I hope you do not, but regardless of it's straightness you sword is not exactly the same as before.

This is one of the reasons that I have always disliked all the meaningless flex testing that people give to swords. A quick bit of research on Young's modulus will show that heat treat has NOTHING to do with flexibility, all it does is move the yield and failure points around. Flexibility is much more a function of the blades geometry than anything. A 36HRC fillet knife will out-flex
a 56HRC thicker bowie blade every time (reverse the HRC numbers and the same still holds). And it all has little to do with impact strength, which I would think is much more important for a sword.

Perhaps one day we may even get all of us bladesmiths to explain what bending blades in vises has to do with a good knife"

I know that my statements may seem like the heresy of one crackpot going against the majority, but it only seems that way in the blade making community. The rest of the steel using world uses these rules to design and build things everyday. Young’s modulus is not my opinion, it is a well established principal of material science. I find a blade that holds an edge and requires more effort than I have to give to break it, far superior to one that bends with moderate force when I need it to stay straight. Bending a knife in a vise is a great test of the smiths skills in heat treating, but it is a lousy test of a knife, in my opinion.

I also worry about elastic strain versus plastic strain. A blade that is heat treated in such a way that the yield point is pushed out of reach of normal work loads, will not retain the stresses and strains of normal use. A blade that bends or deforms plastically will retain that strain permanently and over time it can become problematic.

Sorry but by definition soft spines do not make “strong” blades they just make bent blades. Please don’t get the idea that I am knocking differential quenching here! I play with temper lines myself, and I think they are lovely. But that is the reason I work with them, not to make a “stronger” blade, because they just won’t.

So to make a long story short,( I know ..”TOO LATE”,) I still wouldn’t put 1018 or any other material that I wouldn’t use by itself, even in my swords, and they take a lot more banging than my bowie knives. Not that I haven’t put 1018 or wrought iron in sword cores before to simulate the affects of ancient steel for study. After all not everything is for heavy use.;)

But you are correct that a san mai construction with any material one wishes on the outside of a good cutting steel is a beautiful solution to the problem of performance versus pretty. I have fell in love with blades that were pure nickel/1095 wrapped around a core of O1. Beautiful to behold and very effective to use. Pattern welding is wonderful in its versatility :D :D
 
Kevin, you'll never get anywhere, you're too logical .LOL But this reminds me that many years ago I picked up,for a few bucks, an old kukri, my first. In using it I found that it would bend , in fact if you wacked the side of the blade lightly against a tree it would bend.Needless to say it was immediately retired and I got a good one .So I too am for using good steels and not in the annealed condition .
 
I'm in a jolly mood this morning so I'll just say: lets say the hell with it and go with 'made in china stainless' and be done with it.:) :D Maybe we can get together and do a infomercial.
 
Kevin
The one and only Blade I'm thinking of mainly,
of the ones I make
that benefit the most and the reasons I do this are the
Machetes I make
the cheap ones I've seen and replaced,
work harden then brake and it happens
from the spine towards the edge,
but it happens mainly because of flexing
with the spine being thicker than the rest,
it seams to work harden faster because of this.

one guy in particular I've made 3 for,
is a land surveyor and he may cut a line up to 1500 feet in one day
and he's telling me he's cutting hardwood trees up to 6" with it
( this of the first one I make for him about 4 years ago and still using).
I test them on 5" round wood.
I figure at the very least if it's going to work harden,
it's going to take longer to catch up with the edge
if that is possible..
and I do tell him to send it back at any time to
check the progress of it
(he has not as of yet and it concerns me)..

I'm not saying a dead soft spine, either a spine that will harden
softer than the edge steel in the same heat treat
or drawing it back afterwards,,the only blades I edge-quench are for looks, if the customer
wants it that way, he's the guy paying, what he wants he gets (within reason)
an axe takes 2nd place to the damaging
beaten that a Machete will take and needs to endure IMO.
... If I said that right?

At least the way some of mine are getting used

one of the things that the bend test claims good to, is if the blade is used as a pry bar and it brakes who may be
receiving the flying remains? if it just bends then you'll have at least in your mind, that it won't happen
and in this world of lawyers that should be a good thing..
as you say in normal cutting you can't put enough force on it in normal cutting to brake it
nor would you on a drawn back spine in a pry bar situation, it happens.

but regardless,, different situations do require different means of getting what you want or need.
after all, you have people that will pick up a knife from your table, you tell them it's sharp and they
still cut them selves.
I don't want a part of a Machete I made in someone's leg or worse because
it broke ten years from now, whether I'm liable or not.
 
Dan, if the machete fails from the spine it is not from work hardening but from a fatigue failure. Reducing the chance of fatigue failure is done by strengthening the edge (hardened rather than annealed and making sure there are no deep scratches and making sure there is no decarb). If you customer is cutting 6" trees he should be using something with a good bit of weight like my 24 oz kukri.( yes I'm a kukri man) You have choices but L6 or 5160 at 56-58 edge and 50-52 spine should work well.
 
Mete
I'm not sure if you miss read my post.
mine are not failing and they are not having any problems.
and the spines are drawn back.

the ones he was buying from another out-fit were failing
and their spines were thicker than mine, forged
and not drawn back.

That's why I'm making them for him now.
mine are out of 1095

the beating these are taking (mine)I can't believe they will not work harden,
I'll see if I can get him to loosen up on one to send it back for testing.( after 4 years now)
and of course if it does work harden then it will become brittle
and crack from the flexing am I wrong??
 
1095 is a good steel that I have used for a few years now. I am particularly pleased that you are getting such good results with 1095 in this situation, since it helps put to rest the notion that 1095 has to be more brittle than some other steels. When I took my journeyman test I ran into some problems getting 5160 to consistently perform the test to my satisfaction. Heck they wanted a bent blade, so I fell back to good old reliable 1095 so that I could have absolute control over the varying hardness, worked like a charm;), and this seems kind of contrary to what I see most folks are saying these days.

As for machetes, the only one I have ever needed was an old Longer style Collins that I got when I was a kid and have abused the living daylights out of ever since. I have chooped up trees big enough for most axes, it has never bent, but it doesn't hold an edge like a knife and it sure is springy.
 
Originally posted by rlinger
I'm in a jolly mood this morning so I'll just say: lets say the hell with it and go with 'made in china stainless' and be done with it.:) :D Maybe we can get together and do a infomercial.
Click to expand...

OOOh like those guys on the shopping network!:D :D I will turn the TV to those guys sometimes and my wife will think I am watching a real good comedy or stand up act, from all the laughter comming out of the living room. I love those guys, those knives are SOOOO beautiful! And what a deal " and for a short time only, everything you see here for only $19.95. Yes folks that is 125 of the finest quality knives for only $19.95! Elsewhere you could pay as much as $35 dollars!":eek::D :D

There are times that I have seriously thought of buying some, since I never have a knife on me when anybody asks. I really don't have a knife of my own that isn't on it's way to somebody else, and those ones would be a great match for my wifes kitchen set. Being a big shot Master Bladesmith, I knew that my wife should have nothing but the best and I refused to settle for anything but the best kitchen knives ever made! Thas right, my wife works with a full set of GINSU! It took some real pulling in of favors from a friend who found them on E-bay, and some serious scrimping and saving, but for $0.70 I got the best. And they are the best, anybody who has seen those old comercials know that.

If any of those Ginsu ever die I am going to fold them into a billet and make some "super damascus". Then at the ABS cutting competions the other contestants will flee in terror when my knife is announced!

Or perhaps I will just keep it a secret so that I am the only one capable of making "super damascus" and I can be the greatest bladesmith that ever lived! Hmmmm why stop there when world domination could be within my grasp?... Hmmmm...
 
edited to add hahahaha .:p
you posted justabout the same time I did
and I didn't see that:D
I want some stock in that when the time comes:D :D
*
Thanks Kevin
you know as I do 1095 dead soft will bend
just about by looking at it so yes the spine needs a heat treat
and over the whole blade,then gone from there if
need be for the applications
It's so soft that I even find that if you use it as
a hidden tang it will need H/treating also( the tang) it's some
of the softest steel I've worked with that will work fairly well
I say fairly, I don't like it in hunting applications.
I still like my 154CM for my hunters though.:D
though I am mesing with L6 more now but we'll on that one :)
I still like o1 over it so far,for what I'm using it for anyway
 
Dan, I understood your post, it's the other guys blades that are failing. But you are not getting my point .If you roll or hammer metal to reduce the dimensions you are work hardening . That does not happen at the back of the blade .What may happen is flexing back and forth - that can create a fatigue failure......1095 and other steels of about 1% and higher carbon are usually supplied it the spherodize anneal condition ,that is spheres of carbide in a matrix of ferrite.Yes it's soft and not , for me ,suitable for the spine .....Kevin Ginsu Cashen HAHAHA.
 
Mete
soft is not suitable for the spine,
I would agree to, too soft.

I'm sure the flexing is part of the problem in the ones he had.
I could be getting fatigue failure mixed up with a work hardening failure,

your saying using steel, vibration, flexing and what have you
isn't sufficient to work harden carbon steel?
 
Thanks again for the info, Kevin. I'm waiting eagerly for those results you mentioned. :)

Oh, and, just to keep the idea in the back of your mind, when you get all caught up testing your pet mixes, I (and others) would still love to hear some real numbers on the whole bainite vs. martensite deal. ;)
 
I imagine that I will ahve to get around to the testing bainite thing eventually (of course it will have great impact strength, but how will it be across the board and are the benefits enough?. But the major determining factor in testing right now is the expense in dollars and time. The cheaper stuff gets my attention quicker. Bainite requires that my salts stay hot for a much longer time, and that burns plenty of electricity. I think I already have a very ambitious list of things that I would like to test.
 
"Or perhaps I will just keep it a secret so that I am the only one capable of making "super damascus" and I can be the greatest bladesmith that ever lived! Hmmmm why stop there when world domination could be within my grasp?... Hmmmm..."

Just one problem Ken. You're not Japanese....;)

Tim

P.S. Met Rob Rossdeutscher at a rendezvous. He told me about your Japanese hairless possom....lol.
 
You must log in or register to reply here.
Back
Top