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Jesse Frank

adjusting harmonics

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Hi all,

I have been working on a early viking sword for a couple months now on and off and started evening everything out with a sanding block a couple weeks ago. Problem is that since I started doing this, it pulled the harmonics all out of whack and now the cop near the handle is about three inches up the blade! Is this something that I have to worry about now? Will the furnature help to even this out? I still have some sanding to do, mostly near the tip of the blade in the fuller, it gets a little thicker there. Does anyone know how I can counteract this? Or should I even worry about it?

 

Thanks,

Jesse Frank

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There is a tiny police officer migrating up your blade? :P

 

I've never heard of the center of percussion being discused as a factor in sword making. But I guess a sword does have a 'sweet spot.' How are you measuring it?

 

Does anybody know where the cop should be on a sword?

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I believe that the ideal cop is about two 3rds blade length from the guard and is thought of as the point on the blade were the most energy is transfered from the cut into the target (minimal loss to vibrations), the centre of balance is located closer to the guard (about 4-6 inches). But I have to say that it's a bit of a waste of time worrying about balance before the sword is mounted with a guard and a pommel, pommels are mostly meant as counterweights and the guard will add a little to the counterweight as well. So in stead worrying now try to keep balance well in mind when you make the furnitures.

 

Good luck!! :)

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I am thinking that the pommel will also alter how the blade vibrates. UP till now, the cop has been right where I want it. So it wouldnt transmit vibration to the hand. I guess I will just have to get the handle and everything made before I worry about it. :)

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Sorry to bring up an older thread, but I've been trying to get my mind around the harmonics thing, how does one mesure it, and as a smith how do you go about changing where it is in the sword (or does the sword get to choose?)

 

thanks

Ben

 

is this why the ancient Celts thought their swords had souls (kidding)

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Jesse, You are right the handle, pommel and guard, will all help to bring the COP further back down the blade again.

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gday fellas

i am having a hard time understanding this harmonics thingy .does it mean that if you balance a length of blade between your finger and thumb and then tap the steel while moving the blade you get to a point were the ring pitch is at its highest is that the harmonic balance point or am i thinking off the planet rubbish .

thanks john

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Hi all,

I have been working on a early viking sword for a couple months now on and off and started evening everything out with a sanding block a couple weeks ago. Problem is that since I started doing this, it pulled the harmonics all out of whack and now the cop near the handle is about three inches up the blade! Is this something that I have to worry about now? Will the furnature help to even this out? I still have some sanding to do, mostly near the tip of the blade in the fuller, it gets a little thicker there. Does anyone know how I can counteract this? Or should I even worry about it?

 

Thanks,

Jesse Frank

 

Hi Jesse. It sounds like you are referring to what Tinker calls the "secondary node" which in a perfect world (or perfect sword), should be within the handle, so that vibrations when hitting a target are minimized at the grip. So we are not talking about the blade's COP, but the secondary node at or near to the handle, am I correct?

 

If so, I think adding the guard, handle and pommel will bring the node closer back to the handle. I would think that the secondary node should be affected similarly to what the effect of the completed hilt has on the POB (point of balance) i.e. if attaching the hilt parts pulls the POB back say 6 inches, then the secondary node should also be pulled back some percentage of this distance, of course it all depends on the blade thickness and degree of profile and distal taper... Long story short, I wouldn't worry about it, just keep on building it and see what happens. Oh, and post pictures!

 

Todd

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