vibration in straight swords

[Steven Ott]

While doing various cutting with my longswords and katana, I decided to attempt some phonebooks which where laid out on a table. I have a darksword armory german longsword (not top of the line I know) which is quite a big sword and I had it recently sharpened. When I hit the phonebook, it richocheted straight back up in the air producing almost no cut. My Katana while not cutting clean through stopped dead in the phonebook. In my opinion, I think it has to do with vibration. I can slap my longsword and it wobbles. Slapping my katana does not produce a wobble. I don't know if the curve of the blade negates the vibration.
So my question is: Are straight swords more prone to vibration than curved ones and do the higher end swords vibrate less

[Rob Burroughs]

Perhaps its due to edge geometry. Katanas are exceptionally wide blades with a convex bevel that forces cut material away. If your londsword has a concave edge bevel then some thing as compressable as stacked paper will likely bind up in the bevel.

[Sal Bertucci]

I've cut through several target types with several types of straight edge swords, and have never seen that happen. So I'm at a loss.

[Sripol Asanasavest]

Well, it depends on how well the person uses it, too.... For example, I can cut up a whole chicken better than all the people I know with a dull chef's knife, or French knife. I cut open thick plastic bags with a dull serrated knife. I've seen some lady cooking in the kitchen (I don't remember where...it was a long time ago), and she was cutting the onion, using a knife that was more like a butter knife, going at the speed of light! [chuckle] Not only that, she was using it to butcher the goat carcasses in no time.

[Vincent Le Chevalier]

Hi Steven,

As far as I know (no personal experience here) katana blades are stiffer than European blades, being relatively thick at the spine. Also, the way they are mounted tends to dampen vibrations quite quickly. So It's normal that you can't see a wobble in your katana, while you can see one in the longsword.

What part of your blade were you using?

I have seen one of my own swords bounce (even did it on purpose to test ideas ) when striking a hard target such as a plywood plank resting vertical on the ground. On this kind of hard, unyielding target, striking too far from the node of vibration on the blade (the place where it does not wobble) can produce this result. Basically the blade buckles under the hard impact and starts vibrating, if the part that bit into the target moves too much it jumps out and foils the cut.

Often it is composed with another effect: when you strike too far from the center of percussion associated to your hand, the impact produces hand shock, and then the sword bounces back against your hand which ejects it from the target. Did you feel a kick in your fingers at the moment of the impact?

If you strike near the tip with a longsword, you'll probably see both of these effects. These strikes will work very well on softer targets though... A katana has the center of percussion further towards the tip (well, I think it should At least training sabers have it), so perhaps you struck at that spot, and since it is more rigid too it doesn't give the same vibration problems...

Well that's my experience but it's hard to say for sure without comparing the swords...

Regards,

[RayMcCullough]

If you slap the flat and it wobbles alot, The sword is not stiff enough to begin with. It could be just a poorly made sword.

I wouldn't worry about "center of percussion". That is just a cool sounding sales pitch. Most of the cutting(hewing strikes) is done with the tip(last 5 inches).

[Vincent Le Chevalier]

If you slap the flat and it wobbles alot, The sword is not stiff enough to begin with. It could be just a poorly made sword.

I wouldn't worry about "center of percussion". That is just a cool sounding sales pitch. Most of the cutting(hewing strikes) is done with the tip(last 5 inches).

Tactically speaking yes, but in this situation, cutting at a very dense target that will not give way, I'd say striking further down the blade can give better results depending on the sword.

I know that "center of percussion" has been so wrongly used that it became tainted in the eyes of a lot of people, but that does not mean that the physical phenomenon does not exist (note that I distinguish center of percussion from node of vibration; these can be at the same place or not depending on the design).

Regards,

[Randall Pleasant]

Well, it depends on how well the person uses it, too.... For example, I can cut up a whole chicken better than all the people I know with a dull chef's knife, or French knife. I cut open thick plastic bags with a dull serrated knife. I've seen some lady cooking in the kitchen (I don't remember where...it was a long time ago), and she was cutting the onion, using a knife that was more like a butter knife, going at the speed of light! [chuckle] Not only that, she was using it to butcher the goat carcasses in no time.

Sripol

Your post has absolutely nothing to do with the given topic. This has become a pattern. You have already been warned by another moderater for attempting to turn topics to the eastern arts. This is a second warning. Any other behavior like this may result in the lost of the privilege to be on this forum.

You are welcome to comment if you have something to actually add to a topic or if you disagree with something that was said, or if you have a question. Otherwise, just read.