knife concepts


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kirklandkie
May 26, 2009, 03:04 PM
so, i've acquired a large cylindrical piece of non-magnetic stainless steel which was scrap at a machine shop. it is approximately a half in thick and exactly an 8 inch diameter.
i'm trying to figure out what kind of blade to make from it as the shape does not lend itself to any particular design that i can think of. i'd like to get a fair yield from the material as i don't expect to come into possession of any quality stainless steel any time soon so ideas which would create more than one knife are fair game.
i do have a plasma cutter and some quality grinding wheels so these would be my primary means of cutting the blank and shaping the blade.
thanks

-kirk

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hso
May 26, 2009, 03:14 PM
Pity you can't get it forged flat.

The other option might be to cut it in 1/4" thick sections and the cut various blade shapes out of the disks.

Do you know which "stainless" it is? That will be important for heat treat purposes unless you're willing to go with trail and terror.

kirklandkie
May 26, 2009, 03:45 PM
hmm, no i'm afraid i do not know what type of stainless it is. i just know it is non-magnetic (i have previously dealt in some scrapping so that was the guide to quality).
i wish i could cut it to 1/4 inch but that can't be done with a plasma cutter, and i'm afraid it's far too large and hard to cut with a regular band-saw
what types of stainless are there?

-kirk

kirklandkie
May 26, 2009, 04:04 PM
one thought for trial and error would be to figure out the blanks i plan to cut and then use the remains to temper and test
what do you recommend for tempering stainless?

-kirk

7X57chilmau
May 26, 2009, 04:20 PM
There are hundreds of types of stainless steel, and at least as many hardening and tempering techniques. Unless you can determine the alloy, it's unlikely you'll be able to get a good heat treat on it.

Any way you can figure out what it's an off-cut from? The original purpose of the steel could be a clue to its composition. Certain stainlesses are used in marine environments, certain ones for hydraulic shafting and so on.

Some types of stainless steel are appropriate for blades and many are not (being too soft, for instance).

An 8" disk has me thinking of Xena. I'm sorry!

Spark testing may help you determine the alloy to some degree too:

http://en.wikipedia.org/wiki/Spark_testing_metals

What tools do you have at your disposal for working this piece? That will have some effect on what you can do with it.

J

kirklandkie
May 26, 2009, 04:31 PM
7x57 i have a large variety of tools, the ones i'd deem useful would be:
plasma cutter
die grinder
bench grinder
belt sander
band saw
lets just say i have a plethora of tools at my disposal.
see the composition is difficult to ascertain because it was actually off of a large piece of 8" thick circular stock. crazy stuff, i have no idea what the intended use would be aside from fabrication.
here's a thought, considering the general strength of stainless is it even necessary that i temper it?

-kirk

JTW Jr.
May 26, 2009, 07:56 PM
If you don't know the type of SS it is , how are you planning on Heat treating it ? None of the professional HT places will HT an unknown steel ( that I know of anyways ).

example: 303 can't be hardened by heat treating , to get it to hold an edge. You said it is non magnetic , so that rules out 416

Some Stainless will hold an edge , others won't hold it at all.

You could always send it out to be analyzed , then you would know whether it was worth it or not.
Not sure how cost efficient that would be when you can buy a 3 foot x 1 1/2" x 3/16 bar of say ATS-34 for $50 or so.

hso
May 26, 2009, 09:13 PM
Scrap tool steel can be played with to determine normalization and heat treat.

Scrap stainless is more of a problem when you have all the range of "stainless" to try to figure out the parameters (some of which are very narrow).

Can you go back to the source and ask?

Black Toe Knives
May 26, 2009, 09:32 PM
IMHO Not all Stainless Steel will make a knife. I fear the piece you have unless you know otherwise. It just Plain Stainless. I worked as Machinist for years. Unless we had a special job requiring a special SS for knives on a food grade machine we wouldn't have SS that we could make a knife from. It kind of rare item.

IF you want to make a knife. I have piece of 1095 I will give you if you pay 5.00 for postage. 5/32 x 1 1/4 x 7 Just drop me a line.

kirklandkie
May 26, 2009, 11:29 PM
thank you black but i've already played around with some 1095. i'm still new to knife making but it's something i'm taking to.
re:HSO sorry it's one of "those" situations... i got it from my dad who got it from a friend who got it from a guy at a trade show who got it from god knows where...
i'll just scrap my idea of using this particular piece of stainless for knife making but it is a gorgeous piece i'm sure i'll figure out something for it, even if only ornamental. i would order a piece of stainless for the project but i'm more of a back yard guy in that i don't spend much. i'd try to explain but you'd just have to see my car lmao
thanks for the input everyone, if a mod wants to close this they can. i don't there there is much more we can do here.

-kirk

JTW Jr.
May 27, 2009, 12:26 AM
You could cut it up to use for guards and pommels and such.

Black Toe Knives
May 27, 2009, 12:37 AM
There you go. Guards or sell it and get you good piece of Damascus. How thick was it? That little piece is worth pretty penny.

Zeke/PA
May 27, 2009, 06:21 AM
Non- Magnetic = No Carbon content = non- Heatreatable.

kirklandkie
May 27, 2009, 10:52 AM
i'll probably make some guards out of it, and yea the piece was something i originally was just going to scrap but the scrap market is so low right now i don't even think it'd be worth it.

Non- Magnetic = No Carbon content = non- Heatreatable.
i don't follow your logic, all stainless steel has carbon in it. there are low carbon versions but so far as i know they all have carbon.

-kirk

7X57chilmau
May 27, 2009, 11:02 AM
Magnetism is not related to the carbon content, but to the crystalline structure of the steel. Nickle added to the mix will often force a non-magnetic structure, and enhance anti-corrosion properties....

http://www.azom.com/Details.asp?ArticleID=1140

J

Zeke/PA
May 27, 2009, 06:50 PM
My logic :
300 Series Stainless Low Carbon, Non- Magnetic , non- heatreatable
400 Series Hi- Carbon , Magnetic. heat treatable similar in method to air hardening tool steel in the better 400 series alloys.

KenWP
May 27, 2009, 07:10 PM
Drill a hole in it and use it for a gong at the target range .

kirklandkie
May 27, 2009, 10:39 PM
+1 to kenWP and when i wear it out i'll scrap it

-kirk

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