Using a fuller in the tang

S

Sharp Steel

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Aug 10, 2009
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Some knives have a rat tail, or holes cut in them, to reduce the weight. Has anyone tried using a fuller instead? Seems like that would be a stronger option because the metal is continuous. Someone who knows engineering can probably explain why people don't use that. ;)
 
So if you apply a bending force to a piece of metal, the piece of metal directly in the middle contributes very little to the strength of the part. It's the material at the edges that resist tension and compression the most. If you want to make something stronger for the amount of weight, remove the material in the middle that isn't contributing much (this is how an I-beam works). The difference between hollowing out the middle of the tang completely and machining a fuller is basically just a little sliver of metal that isn't adding much to the strength, so you might as well cut it all the way through. You'd put a fuller on the blade so as not to create a cutout that can get material stuck in it or snag, but on the tang this isn't an issue since it's covered by the handles.

Also machining a fuller is kind of a pain because you need to use a bullnose end mill on both sides, and run it slow enough to maintain a decent finish. If you're making a cutout and not chamfering it, you can rough it with a waterjet and maybe clean it up on the mill, or wire EDM it and leave as-is.
 
Paul ( CPE_Knives CPE_Knives ) does fullers in the tangs of his knives. Two of my favorites (his photos):

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ferider said:
Holes and/or fuller - as these knives are not CAD designed but sketched on paper - I feel the real art is to predict the balance point and overall weight correctly, after the scales are glued and shaped.
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It's a great point you make about balance, one that a lot of makers overlook. It's a big reason I love stick tangs as well as natural wood scales.

A well balanced knife can feel 3x lighter in hand than a poorly balanced knife of the same weight.
 
Several of the newer Chris Reeves fixed blades actually skeletonize what would be a full tang. Check out their "Backpacker" model for this.

Then there is the Loveless tapered tang seen on his iconic drop point hunter.. Not an easy thing to do in the home workshop (for me anyway).

The easiest way to lighten a full tang is to just drill holes in it.

I would think that fullers would need some sort of milling operation.
 
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DeadPineKnives said:
Until you realize you have to drill those holes on 10, 20 or sometimes 50 knife blades.... I speak from experience!
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To clarify, I would say that drilling 5-6 holes 5/16" in diameter in a piece of steel .125" thick takes about 10 seconds per hole, not even counting running a countersing, guesstimatiously speaking. Meanwhile, grinding a fuller from the top pin hole to the lanyard hole (or to the end for a tapered tang) takes, say, about a minute with a 60 grit belt. I'm less interested in burning up $7 HSS drill bits than I used to be.

VorpelSword said:
Several of the newer Chris Reeves fixed blades actually skeletonize what would be a full tang. Check out their "Backpacker" model for this.

Then there is the Loveless tapered tang seen on his iconic drop point hunter.. Not an easy thing to do in the home workshop (for me anyway).

The easiest way to lighten a full tang is to just drill holes in it.

I would think that fullers would need some sort of milling operation.
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A tapered tang is actually quite easy and doesn't require any specialized equipment! As long as you have an open idler wheel and a decently flat platen on your grinder, you can grind a tapered tang!!

My trick is to use the bottom idler wheel on my grinder to grind a fuller, grinding all the way past the butt of the knife to the final thickness I desire (about .02-.03"), though Loveless used a 4 or 8 inch contact wheel. Then using a welding magnet I grind the tang down to a taper! Literally you could even use a 4x36" belt sander with a piece of glass glued to it for a perfect platen. Or even a disc grinder!

Never, ever assume that something is harder than you think it is, because then you'll never try it!
 
VorpelSword said:
The easiest way to lighten a full tang is to just drill holes in it.
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No, the easiest and fastest way is to grind a fuller with a small diameter wheel.

VorpelSword said:
I would think that fullers would need some sort of milling operation.
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They absolutely don't. Most handmade makers do it by hand on a belt grinder. I could do it faster by hand than it would take to just set up to do it on a mill.
 
kylemiller said:
Oh man! I've never heard of this fella but I LOVE this! I'm a sucker for novelty fullers. This guy is speaking my language! Now I'm gonna figure out how to get one.
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That style fuller is reminiscent of cut down bayonets. Either to have shorter bayonet or to make a knife out of a bayonet.
 
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