Questions for the bladesmiths, on altering a blade

Discussion in 'Chinese Swords and Sword Arts' started by Flying Crane, Mar 28, 2017.

  1. Flying Crane

    Flying Crane Sr. Grandmaster

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    I have several Chinese jian, double edged straight swords, that I have acquired over the years, some of which were made in the 1970s and 1980s, when the Chinese companies were still making robust blades. These are thick and heavy, not flimsy wushu toy weapons. As such, they are heavy to the point of being unwieldy, and I am considering attempting to do some alterations.

    The blades are flattened diamond shape in profile, with a central spine, and no fuller. I am considering grinding them down on a belt sander, to flatten them and possibly make a fuller.

    I do not know what type of steel these are, nor if they are properly tempered. For the sake of discussion, let's assume they are of a "decent" quality and type of steel for a good blade, and the tempering is proper.

    If I do this, and cool it in water periodically, is it possible to succeed without destroying the temper? I am not in a position to have them retempered.

    Any thoughts on how I might go about this?
     
  2. Brian King

    Brian King Master Black Belt

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    Have you seen the tv series (history channel I think) Forged in fire? It is available on Amazon streaming. From what I picked up watching several shows and with hardly any experience at all, but, FWIW and In my opinion -

    Every contestant so far that has quenched their forge in water has had cracks in the metal but not so with oil,,,on the other hand, they had lots of fire with oil. With grinding you wouldn't or shouldn't get the blade so hot that it effects the temper (as long as they were indeed tempered) I would think you can grind and cool with water, just avoid getting the blade orange or red, sparks are OK.

    The judges checked the temper by doing a "file test" by taking a small metal file and running the file down the edge of the blade. If the file grabbed or bit - not tempered. If the file slid - tempered.

    Even though the show is "forged" there is a lot of grinding. You might be interested in it. I have enjoyed it, although my wife hates it. She has extensive training working with metals and physically cringes at the mistakes in the making process of some contestants and the abuse of the knives and swords during testing.

    Good luck and take so me before after pics!
    Regards
    Brian King
     
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  3. Flying Crane

    Flying Crane Sr. Grandmaster

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    So would a blade need to get red hot before it would affect the temper?

    If I can still handle the blade with bare hands, or thin leather work gloves, it would be cool enough that the temper would not be in danger?
     
  4. hoshin1600

    hoshin1600 Senior Master

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    just a suggestion, why not bring it to a machinist? or a blade smith if you can find one. not passing judgment on you, but for most people what you are trying to do usually comes out looking like crap. and most likely you will discolor the steel and the temper.
     
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  5. Flying Crane

    Flying Crane Sr. Grandmaster

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    Interesting thought, and honestly I never thought of it myself. I don't know if there is a competent bladesmith nearby, but I can research that. I didn't think of a machinist.

    I'm kind of do-it-yourself with sword modifications, I've rebuilt a bunch of hilts and scabbards for jian and for dao, casting the metal fittings in bronze and silver. I've not done any steel work, tho, but the challenge is interesting and I am reluctant to spend real money on it given that the actual quality of the blades is unknown, and while possibly "decent", unlikely to be superior.

    I do have a couple other cheap blades I could sacrifice first, to see how it comes out before I try one of the (possibly) better ones.
     
  6. wingerjim

    wingerjim Green Belt

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    These are likely low allow steels and the temperature where the temper is lost is lower than in high quality allows, which would be the case if these are actual swords vs training swords. If they were mine I would first consider adding some weight to the handle and even though this makes them weigh more they would be better balanced and easier to handle when training. If this is not feasible, then I would try to find a machine show to mill off material, which does not heat the metal anywhere close to the degree that would change their properties. The problem with sanding is that a lot of friction is part of the process, which quickly heats up the metal and can easily change the temper and make the blade fragile. If you have ever sanded metal and you get a blue color like the color shown to the right. If you proceed very slow and take a lot of time and keep the metal like on the left, you would be fine but it may take a long long time. [​IMG]
     
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  7. Flying Crane

    Flying Crane Sr. Grandmaster

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    I have already rebuilt the hilts and given them solid bronze guards and pommels, so the weight redistribution and rebalancing has been done as well as possible. Now they are simply heavy and the only option that remains is to lighten them through material removal in the blade. That would further help with the balance as well.

    I am familiar with the discoloration you reference, you sometimes see it on drill bits that get dull and are pushed through some hard wood. That is what I was wondering about, it that is actually a damaged temper if it changes color like that.

    The makers of these are Lung Chuan and one of their competitors I can't remember the name, but this can actually mean several different makers and I doubt it is possible to find out what kind of steel it is, especially considering they were made decades ago.

    Anybody know of some simple, non-destructive tests I can do that might hint at a type of steel?
     
  8. wingerjim

    wingerjim Green Belt

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    One way would simply be with a magnet. If they hold a magnet they are carbon steel, if not stainless. The next way would be to use a file in an area covered by something and see just how hard it is say compared to your lawn mower blade, which is about medium hardness or on the non-business end of a drill bit, which is rather hard. If you run the file over the hilt for instance with light pressure and the file cuts, it is soft to begin with. However if the file just wants to skip with anything other than hard pressure, the blade is hard. I would guess they are a mild stainless steel. Stainless steels have a lot of chrome, which makes them harder than untempered carbon steel but susceptible to the kind of staining noted previously in the display. If the blade is carbon due to a magnet sticking to it, you are in more luck because the carbon allows for more heat dispensation than the chrome and you can sand it with care without changing the temper. The only exception would be in the unlikely even they are case hardened. If they are case hardened and you sand off material, you are removing the hardness and will only be left with soft steel. The only way to tell if it were case hardened would be to cross section and polish the cut to see if there is a case on the steel.
     
  9. Flying Crane

    Flying Crane Sr. Grandmaster

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    Interesting ideas, but I do believe a magnet will stick to any steel, including stainless.
     
  10. Flying Crane

    Flying Crane Sr. Grandmaster

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    I am confident that they are not stainless, actually. I know they had some cleanup done to remove some rust after the years and they just don't look like stainless. I guess I'm wondering if there is a way to determine the carbon level. If it has enough carbon for a decent blade, then it's a good start. I will assume these are simple carbon steel of some kind, and not an exotic alloy or high end type like 5160. But if the carbon is too low then it affects how well it can be tempered and whatnot. If there is a way to test for that, that isn't destructive to the blade, that would be useful. I'll try the file trick tho to see if it is hardened, and I could maybe smack the edges with a wooden dowel and see it it turns the edges or shows immediate damage. That might give me a hint.
     
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  11. wingerjim

    wingerjim Green Belt

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    Actually it will not to all SS because not all are ferromagnetic. Take your SS forks, spoons and knives, they likely are not ferris because they do not need to be. Here is the definition of ferromagnetism from Wikipedia: Ferromagnetism is a property not just of the chemical make-up of a material, but of its crystalline structure and microstructure. There are ferromagnetic metal alloys whose constituents are not themselves ferromagnetic, called Heusler alloys, named after Fritz Heusler. Conversely there are non-magnetic alloys, such as types of stainless steel, composed almost exclusively of ferromagnetic metals.
     
  12. Flying Crane

    Flying Crane Sr. Grandmaster

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    So content of iron or iron derived materials like steel, even if that material is the bulk of the makeup, does not always make it magnetic? The additives that make it stainless, like nickel, can eliminate the magnetism of the iron?
     
  13. Flying Crane

    Flying Crane Sr. Grandmaster

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    Ok I did a quick google-fu and it seems that stainless often is magnetic, but some types of stainless steel are not.

    I did not know that.
     
  14. hoshin1600

    hoshin1600 Senior Master

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    stainless will have a magnetic attraction of varying degrees depending on the carbon in the steel and the amounts of nickle or other metals. so some stainless (expensive stainless will not attract a magnet) others will.


    Stainless Steel - Magnetic Properties
    " Except austenitic grades, all types of stainless steels strongly respond to a magnetic field.

    Austenitic stainless steel grades exhibit low magnetic permeability, because of which they do not show any response to magnets in the annealed condition. However, they show some amount of magnetic response following cold-working process, such as heavy polishing, shot blasting, centerless grinding, rolling or wire drawing. Grade 304 steels attain quite strong magnetic response following substantial cold working, while grades 310 and 316 will remain non-responsive to a magnet in most cases.

    Variations in magnetic permeability are mainly due to factors such as martensitic formation and atomic lattice straining. Generally, magnetic response due to cold-work will be less in the conditions of higher nickel to chromium ratio. Therefore, magnetic response is only used for classifying different grades of stainless steels."
     
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  15. Bino TWT

    Bino TWT Green Belt

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    You are dealing with unknown steel of unknown quality and no idea of the heat treat or temper. You're asking for trouble... find a bladesmith.

    Aside from just ruining your weapon, you could potentially make it very very dangerous for you or anyone around you.
     

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