lateral bend in blades?

[Dan H]

I noticed, after using a Prieur FIE foil blade in practice and competition for a couple of months, that it had developed a lateral deflection of about 2-3 inches. It deflects to the right if I sight down along the blade from the handle. Since I'm right-handed, I didn't expect it to bend this way. Most of the curvature is in the middle-weak part of the blade.

I tried bending the foil blade to the side to straighten it, just like we all do with up-down bends. It bends that way, but won't seem to straighten - it just wants to hold that lateral bend. I then ran the blade under my foot on top of a carpet until it was too hot to touch, bent it to straighten, pinned it bent in place, and left it for about a day. That didn't seem to do anything, either.

Last night I went to grab one of my other blades, so I'd have one that's not bent to the right (and technically illegal because of it) to fence with, and noticed that every one of my blades has a deflection to the right! If I've put it through significant use, it's got a lateral deflection to the right. Some are very gradual, some are more precipitous; some are about an inch deflection, one (the Prieur) is about three. But, I don't have a single straight blade in my bag, FIE or cheapo brand, at the moment.

Does anyone else have this problem? And how the devil can I work that lateral bend out of my FIE blades?
Thanks...

[noodle]

well, i'm reasonably sure that it happens just like every other non-radical bend in the blade. i suppose that means that after you hit, you tend to shift your hand inward in relation to the point, which puts strain on the blade to bend out to the right.

of course, thats only a guess, because i doubt there's a defect in all of your blades.

work the bend out the same way you work out a bad vertical bend. warm up the blade (rubbing with a towel, the shoe-carpet deal, etc), and try and gently correct the bend. use the blade to hit a target and put a proper bend on the blade, maybe shift your arm to the other side in order to try and force the bend back to the center. but the bends will come back if its a problem in your form. should try and fix that first if its the case. get someone else to watch what you're doing (its probably something that occurs in bouting more often than drilling, keep an eye out)

thats my $0.02 on the issue

[The0ne]

In my opinion the whole "heat up the blade" thing doesn't work. I can sometimes work those kind of bends out, regular leon pauls get that sort of bend kinda naturally. If you're going to summer nationals, I could give it a try, but other than that, do the "bend under your foot" thing and don't be afraid to put a significant amount of pressure on the blade!!!

good luck!

[CarlKnoch]

Here's a nifty theory.... I wonder if it is true.....

When you fence with a blade and do lots of parry 4 and lots of beat attacks, you might find that your blade is curving right. As you start a hard motion with your blade to parry 4, the blade is flexing to the right as it goes through the air. The blade hits the other blade and is immediately shocked. This vibration causes the blade to become slightly bent the way it was when the impact occurred. Makes me wonder if there is a righty fencer out there who fences with lots of counter 6 and beats to six with just the opposite happening.

[noodle]

Here's a nifty theory.... I wonder if it is true.....

When you fence with a blade and do lots of parry 4 and lots of beat attacks, you might find that your blade is curving right. As you start a hard motion with your blade to parry 4, the blade is flexing to the right as it goes through the air. The blade hits the other blade and is immediately shocked. This vibration causes the blade to become slightly bent the way it was when the impact occurred. Makes me wonder if there is a righty fencer out there who fences with lots of counter 6 and beats to six with just the opposite happening.

i'm no physics expert but i think that won't cut it.
the reason being that the response to the force put on a blade is different. normal extension has constant force thats applied to cause a reasonably elastic deformation because the blade has nowhere else to redirect the energy and its crystalline structure is designed to bend that way. on a beat or a parry, though, the force from one blade is redirected into motion of the other blade (which is sometimes compensated in the muscles of the opposing fencer), into inelastic deformation (actual dents, sometimes splintering of the metal), sound, etc. and the blade is less likely to take a bend like that because its fighting the crystalline structure.

someone that actually knows some physics is welcome to call bs on me and correct this

[CvilleFencer]

My prieur FIE got the same kind of bend after a couple of tourneys. I think it is just a trait of those blades. Mine straightened out without to much effort, though it rebends that was after a few bouts.

[Dan H]

Well, I guess I'll go back to the old rub-it-under-the-foot-and-bend-against-the-floor method for now. It's difficult to get the blade to bend laterally - if you're not careful, the blade twists a bit in your hand and ends up bent vertically, which of course is the way it likes to bend. I wonder if the lateral deflection will be easier to bend out of the cheap blades than out of the Prieur.
I actually probably do qualify as a "physics expert" on the related issue that popped up (I'm months away from my doctorate in physics, and I work on materials properties), but I don't have a handy answer for you, Noodle. Materials properties vary vastly from system to system, and I'm not familiar enough with the metallurgy of FIE fencing blades to know what alloys are used, what the macroscopic structure of the blade is (is it just one piece of metal, or is the core a different material than the exterior?), what its annealing history is, what its average grain size and texture looks like, etc. You'd want to know something about all those before you could make reasonable predictions about how the blade reacts to different types of strain. That is, as a physicist, I look at this sort of problem as "hard," and I tend to go look at simpler systems (such as 99.999% pure aluminum) when I want answers. What we really need is a materials scientist who works with steel alloys, or just anyone who knows how FIE blades are forged. Maybe if I give up on my Prieur blade ever being straight again, I could take the band-saw to it, cut and polish some samples, and convince my advisor they're interesting enough to stick them in various microscopes and look at the structure. For now, though, I'd rather get the darned thing straight so I can fence with it.

[telkanuru]

The work might actually be done for you. The maraging techniqe is (I think) sometimes used in very high end springs, due to the alloy's remarkable ability to withstand many distortions while returning to its original form and not breaking, so there are bound to be datasheets out there somewhere. Small Parts (tm) sells them, I think. Hm. That had a lot of "I think"s. Oh, well. Perhaps we could get a manufacturer (we have them here, right?) to comment on the construction, unless it's a trade secret

[Dan H]

Well, after several unsuccessful attempts to heat up the blade and correct the bend gently, I finally just decided to put the thing under my foot and bend it beyond the point where I thought it was likely to snap. It worked. I don't know if I did anything nasty to the blade, but the lateral bend is gone. It was much easier to work the lateral bend out of my non-FIE blades - just heat up and bend normally. If anyone else has this problem with Prieur FIE blades, it seems the solution is just to bend the heck out of the blade, and if it snaps, it snaps.

[The0ne]

told you the heat-it-up-under-the-foot method was bunk!! That's what I do, seems to have worked for ya, well done.

[kalivor]

A guy at my club has this problem. The cause?

A tendency for his elbow to come up and out as he makes a hit. The blade just bends that way ... after so many repititions, they've become permanent.

He's bought some cheap practice blades to use while he attempts to correct it.

[geezer]

If you're right handed, picture this...if you deliver the tip 'palm up', like I do most of the time in foil, and finish with a push to arch the blade, you can't have anything BUT a right handed bent in the blade. I sure do. Or, trying to remise from right to left, hitting and continuing to push the hand to the left will do it too.

Try putting the blade through the hole of a closed-end 1/2" wrench and GENTLY use it as a pry-bar lever. Maybe yes, maybe no.

Have a nice bout.

non illigitimi carborundum.

[Dan H]

Bah - although I found I could keep the blade straight by bending it hard sideways from time to time, the other day it snapped on a beat. My opponent put out a little half-attack; I made a sharp beat with intention of continuing my attack; the blade snapped about 6 inches from the tip, and the top part flew across the salle. That's the only time I've ever broken one of my foils when it wasn't being bent either against my opponent or to straighten it. FIE blade, used for maybe 3 or 4 months. It's probably because I had to bend the thing sideways 2 or 3 times to straighten it, and that stressed the blade at that point. Hopefully I won't snap my other FIE blades the same way.