Preventing your blade from breaking early

[o4aversob]

Hello, I had France-Lames practice blade of good quality that lasted for only about 5 months. I was wondering if there is anything i can do to maintain my next blade's strength so it doesn't break so easily. Does anyone know what I could do? Thankyou

[veeco]

Prebend it with the correct curve. Make sure you hit correctly. And pray!

[npkeith]

Make sure you sand down or smooth out the little nicks that invariably show up. They tend to be the starting point for cracks.

[Marcos]

is that correct?

I'd have thought sanding down would have made the weapon brittle and weak...

[neevel]

Those nicks create stress-risers-- smoothing them down will reduce that effect. Be aware, however, that you can't be too aggressive with them, as the rules specifically prohibit any post-manufacture grinding or heating of the blade forward of the tang. Anything you can accomplish with a sanding block or a wire-wheel is fine, but taking a file or grinding wheel to it is a no-no.

Aside from that, pre-training an even, downward curve is the key thing to do. The limit for a foil blade is 2 cm curvature.

There is one more big way to prevent premature breakage: spend the money up front for an FIE blade. The improved durability will more than pay for the cost of the blade.

-Dave

[picojeff]

Originally posted by neevel
Those nicks create stress-risers-- smoothing them down will reduce that effect. Be aware, however, that you can't be too aggressive with them, as the rules specifically prohibit any post-manufacture grinding or heating of the blade forward of the tang. Anything you can accomplish with a sanding block or a wire-wheel is fine, but taking a file or grinding wheel to it is a no-no.

Is that really legal? I have never seen nor heard of anyone doing this. Not that a small file mark would be noticed by any armorer doing weapon check, outside of world championships...

There is one more big way to prevent premature breakage: spend the money up front for an FIE blade. The improved durability will more than pay for the cost of the blade.

I think the variability between manufacturers and each production run is far greater than the difference between FIE and not. I have used only FIE blades for a long time now, and if one lasts 12 months I start thinking of it as old. I know people with non-FIE blades that last them 4+ years. Perhaps the difference is fencing style, and how often each blade gets used, but I have doubts.

[o4aversob]

Thankyou everyone for your comments. I'm thinking of getting a maraging blade, since I do a lot of fencing.

[neevel]

Originally posted by picojeff
Is that really legal? I have never seen nor heard of anyone doing this. Not that a small file mark would be noticed by any armorer doing weapon check, outside of world championships...

I think the variability between manufacturers and each production run is far greater than the difference between FIE and not. I have used only FIE blades for a long time now, and if one lasts 12 months I start thinking of it as old. I know people with non-FIE blades that last them 4+ years. Perhaps the difference is fencing style, and how often each blade gets used, but I have doubts.

I think you misread my post-- grinding or filing beyond the tang is illegal. On the other hand, sanding or abrading as you would do to remove rust is perfectly accepatable.

The difference you notice with people having non-maraigng blades last 4 years is almost certainly due to usage patterns. The cheap non maraging dry blades I use for my club's practice foils typically last 2 years or more, but that's because they're being used almost exclusively in a controlled instruction environment, not in hard bouting. Maraging steel (or non-maraging steels that can pass the FIE's homologation tests) is intrinsically stronger than ordinary carbon steel, and will on average last much longer.

-Dave

[Barry Paul]

If your blade lasted 5 months you were either lucky or not fencing hard enough. When France lame was Hostine 25 years ago.(when their blades were considered better than the subsequent France lame blades) As a world class fencer I broke 30 to 50 blades a year say 1 every week.

Due to the mechanism of failure it is unlikly that smoothing the blade with a polishing block will extend the life of a blade significantly.

The answer is to use a maraging blade, In the Uk the price differential between the electric standard blade and the maraging blade is that once you break a standard blade you would have almost saved money if you had started wiith a maraging blade which last depending on your fencing 5 to 10 times longer.
In the U.S. the case for maraging is not so strong due to the cheap and in general poor quality blades being sold. Of course the fencers don't care because it is his oponent which is injured by a broken blade. I wonder when the first action in the US Law courts will be brought by an injured fencer against a fencer or a vendor for using/selling goods which are known to be of inferior quality, and not fit for purpose.

Blades presently being offer as F.I.E. non maraging I have some doubts regarding their life in actual fencing. The high stress low cycle fatigue which is the mechanism for blade failure is dependendant on the K1C value which is a figure which determines the rate of crack propergation. I would like to know what the K1C values are for these blades. Barry Paul M.D. Leon Paul

[Barry Paul]

I have just re-read the original post to see a practice blade is mentioned, if this is a non-electric blade please consider I was talking about electric blades Barry Paul

[pammie003]

I've been using the same non-FIE blade since before Christmas, fencing 2-3 times a week (6-12 hours) and it's still going strong. It's the Allstar Super. I bought it because I liked both the balance and stiffness, whereas all the FIEs I tried out just felt a little off... I guess I just lucked out. I'm hoping it'll last me until October or so, when I first see an equipment vendor back in Canada. I don't think the same one is available there, so I might go with an FIE.

[JEC]

Originally posted by Barry Paul
The high stress low cycle fatigue which is the mechanism for blade failure is dependendant on the K1C value which is a figure which determines the rate of crack propergation.

Barry,
Thanks again for the whisky. How the K1C value is calculated? It is an empirical value based on testing? Or is it a calculated byproduct of some specifications?
Thanks,
JEC

[Barry Paul]

K1C value is measued by testing. Known materials heat treted to a given hardness will have indicative K1C values typically 120 for maraging steel.

[Wizardly]

K1C is experimentally determined. The higher the number, the more resistant to crack propagation under static loads. I suspect fatigue has a lot to do with blade breakage. One of these days I'm going to get bored enough to do a stress analysis.

I suspect it's a European unit (rather than SI or English): can anyone tell me what Mpay is? I'm hoping it's a funky spelling of MPa.