deep hollow grinds

RARanney

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Some of the Japanese style, and martial arts style blades have a very deep hollow grind, as though done with a one inch, or so, contact wheel. Is it that simple or is there a trick I'm missing. Thanks.
 
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I know that for some of the europian blades, you start by forging 3 fullers. the outer ridge is beaten down to form the edge. this gives you an I-beam between 2 narrow blades (very strong stiff and light ) these look very sharply hollow ground, but they are beaten in.

Is this what you are talking about?
 
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I expect Eric is correct although on most good swords from Japan, they have a traditional polish. This is a very flat, very fine, edge. It is also a pain to do but gets so sharp it can split atoms. Sometime I'll have to explain my controled linear fisson technique.
 

RARanney

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Actually I was referring to some of the stock removal tantos (probably not very authentic but cool looking) and balisongs. The edges of some are actually like a fuller, very deeply "grooved", but only a short distance from origin to edge.
 

RHINOKNIVES

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its a cheap way to put a edge on a piece of steel. you are removing as little as possible.
 
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A smaller diameter contact wheel accents the depth of the grind because of the steeper transition. Try grinding with a 6" diameter wheel and you will see a major transition.
 
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The ones with the deepest looking hollow grinds tend to be chisel edged so you get 'twice' the depth with thick stock. Very attractive. Chisel grinds for a right hander should be IMHO be on the right side of the blade so the flat part is facing you when cutting. This pushes the blade into what you are whittling vs being pushed out of the work when ground on the left face of the blade. For a vertical cut, it probably doesn't matter. Mike Snobodny (sp?) does lots of these although from several pictures I've seen he tends to put the chisel side on the left side of the blade. I'm guessing for eye appeal since most blades are pictured with the left face showing.
 
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Snody does the chisels right. When fighting, a most often movement made is a #1 slash: using your right hand, you slash fromright shoulder to left hip (diagonal across your body), or you slash horizontally, again from right to left across your body. This elaves the flat side DOWN, shich is where you want it to be when cutting. On his smaller chisel ground utility pieces, he reverses the grind to make the cutting more efficient. The flat is on the left side for right handers. Snody knows the light... :cool:
 
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OK..I've heard enough. I'm going to have to explain the reason for the deep hollow.
Now this will only work with certain, very sharp knives. When you sharpen you must leave the wire edge. It helps if it is just after a rain so the air is a little heavy}

Stand facing your victim at any distance up to 20 feet. (longer with practice)

Strike as if you were using a fly rod and end the swing aiming directly at the victim.

The thick side of the blade creates a vortex or high pressure area between you and the target, shaped like a tunnel.

The very sharp edge splits several atoms in the process.

The split atoms fly around and hit the pressure walls and bounce back splitting more atoms.

Since the only low pressure area is the hole where the target is, the energy all flows that direction.

I once killed a bear at 200 yards using this technique and several razor blades sandwiched between two tent stakes.:D
 
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