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Thread: Any hope for my BF Blade?

  1. #1
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    Any hope for my BF Blade?

    Hi all, my Uhlmann BF blade is only about 2 months old and it's beginning to show kinks (S-shape) when i fence. I've initially gave it a nice curve by bending it. But when i fence (especially close quarter hits), the blade bends in the other way giving it a 'snake' bend and i always have to bend it back to shape. This happens almost EVERY hit. It seems the blade cannot sustain its shape

    Is it inate? As in there's nothing i can do about it?

    thanks in adv!

  2. #2
    Senior Member telkanuru's Avatar
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    First thing is watch how you hit. Almost all my team's foils have s-curves in them, because a certain fencer hits an opponent in a certain way that's garunteed to s-curve the blade every damned time. I gave him a nice talk about this, and he's changed his ways.

    Second, try 'training' the blade. Someone on this forum told me how to do it a while back. First use a cloth to heat the blade by rubbing. It should be at least warm to the touch. Then form it a bit by bending. Repeat until you have a desired curve. If that dosn't hold, start saving your money
    "We are what we repeatedly do. Excellence, therefore, is not an act, but a habit." -Aristotle

  3. #3
    Senior Member cowpaste's Avatar
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    third, get maraging.
    "That's hot." - Paris Hilton

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    Sometimes it cannot be helped when you try to hit your opponent. Especially when both lunge and catch each other at the same time. If i'm lucky, i can catch him on my curve, otherwise the blade will just kink in the opposite direction giving a very prominent bend near the tip and i will have to bend it back. My previous BF blade doesn't give me this kind of problem ( it lasted for 2 yrs before breaking) ...this particular one looks like it cannot last past 1/2 a year.

  5. #5
    Senior Member veeco's Avatar
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    Make sure you are raising your hand when hitting. Always raise the hand and follow through. It doesn't have to be a strong follow through, but it should be smooth, and should be dosed depending on the distance you are from the other fencer. That will make your blade bend correctly when you hit.
    • Epee is the Louis Vuitton bag of fencing: only the best can get it, and the rest of the masses must content themselves with cheap knockoffs (sabre, foil)
    • To not recognize the power of the French grip is to be in denial

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    hmm...good point. Point taken, thanks!

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    Senior Member shlepzig's Avatar
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    Heat the blade? (beware of mind numbingly dull post)

    Quote Originally Posted by telkanuru
    First thing is watch how you hit. Almost all my team's foils have s-curves in them, because a certain fencer hits an opponent in a certain way that's garunteed to s-curve the blade every damned time. I gave him a nice talk about this, and he's changed his ways.

    Second, try 'training' the blade. Someone on this forum told me how to do it a while back. First use a cloth to heat the blade by rubbing. It should be at least warm to the touch. Then form it a bit by bending. Repeat until you have a desired curve. If that dosn't hold, start saving your money
    Sound of geek engineer hat coming out of hiding.

    The repeated bending will do some work to the grain structure in the steel, but heating it by rubbing it with a cloth seems to me like it would do nothing. I have not researched all of the processes used in properly tempering a maraging blade, but I can not imagine the amount of heat you can generate with your hand and a cloth would be significant to steel alloys here.

    Materials of this sort have several basic properties, but let's just summarize them as hardness and toughness. Hardness being it's ability to resist any deflormation (like a rock is hard), and toughness being it's ability to spring back from deformation (like a bungee cord is tough). There are also two types of deformation to consider, plastic and elastic. Plastic is bending, and Elastic is springing back. Then there is ultimately failure, when it all goes to pot and you to buy a new blade.

    Basically steel is bunch of little grains of different size and shape and hardness squished together. These grains are the individual crystals of the steel alloy. All the processes in steel making and tempering adjust the chemical composition of those grains give the steel the particular properties that we look for in a good blade (or hammer or spring or whatever, blades here for the conversation). Those grains can change shape when they are subjected to deformation (bending, forging, stomping on, etc.) or when subjected to enough heat to cause either the crystals to relax and either melt or release (or pick up addtitonal) some of the chemicals (alloying materials, carbon being the bugbear with most steels) within the crystalline structure. Anybody familar with most any form of metal working is familiar with annealing which is done at low heat, but not at something you could do with a cloth or hand.

    When you put a bad bend in a blade you have done a bunch of things to it. Firstly you have deformed those little grains. This is OK, the structure of steel is such you can do this pretty forgivably. Also in the bending you have heated up some of those grains pretty hot and changed some of their compositions or structures. They cool down and dissipate heat pretty quickly to adjacent grains but the damage has been done. Basically that spot is now a little softer (or harder) than it was before the hit. If that spot is softer (or less tough) than spots adjacent to it next time you have a bad hit that location is more likely to give than other parts of the blade. Now all the physics of a blade bending within a hit are pretty daunting (someone posted pictures of S bends during touches to illustrate the dynamic physics of a touch, pretty cool stuff, and illustrates that there are a lot of forces running up and down that blade for a moment) but basically that soft spot comes into play with every touch in relation to the physical properties of the rest of the blade. So you can get several bends or soft spots running in a blade, and they may seem to come and go (with other spots getting harder or softer). As one spot starts to accumulate this damage a process called work hardening occurs.

    Work hardening is when those little grains get worked (thorugh deformation) into tight little shapes and the dislocations (little spaces between the grains) start to get stretched out decreasing the surface contact between the grains (like sand in your sand castle drying out where the surface tension from the water increases the contact strength between the grains of sand, similar physics, bad analogy). Then that spot is less able to deform and is more likely to break when bending.

    Then you have to get a new blade.

    Short answer (inappropriately located at the end of the long answer), not a lot you can do other than try to reshape the blade to a consistant shape to reduce the amount of stress on that weakened spot. It's life is shortened each time you bend it like that. More so if you bend it in the same spot.

    Shlep,
    (having just defeated the 6hd Engineer within)

  8. #8
    Senior Member MyraTrue's Avatar
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    Bobic,

    the only thing I can add to all of this is that I had similar problems with an epee blade of mine. I bought the entire weapon, used, off a club mate. But it had spent a semester in rotation amungst the male fencers, and has been sorely abused. It sported a lovely set of kinks and usually had to be beaten back out of its S-curve shape.

    If its any consolation, I fencer heavily with it for another... 11 months before it finally died the first of January. So there may yet be life in the blade, but the curve will certianly be annoying. Mine got to the point where at every point I'd have to rebend the blade and I KNEW it was going to break. But it served me well, despite the kink, all the same.

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