Fullers

R

Raymond1000

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Oct 8, 2006
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This may be covered in Bladesmithing for Dummies. Alas, I’m no smith of any kind.

A machinist friend told me fullers were developed to help making single edged straight swords. He said forging a single edged naturally produced a curve since the edge side of the sword is worked more than the spine side. Hammering a fuller below the spine balanced things.

I have my doubts because I’ve seen straight single edged swords without fullers. Some of those must have been made by stock removal. But older swords would have been forged. I’ve always supposed that fullers help keep a sword to a manageable weight. Not that the ideas are mutually contradictory.

Does his theory make sense to anyone here?
 
The reasons fullers were used is pretty much open to speculation, since medieval smiths weren't into the written word as much as modern ones. Weight reduction is the most obvious and most probable, but when forging them you don't actually make the blade lighter, you make it wider, without increasing the weight or using additional material. It seems like a small difference until you consider the relative scarcity of good quality steel during the period(s) in question.
Single edged swords are generally less common than double edged ones before and during the medieval period, and fullers are common on the two edged variety as well, so your friend's assertion as to their origin sounds dubious at best, although they would indeed have the effect he stated (I have observed it in practice).
 
There are easier ways to forge a single edged sword with little curve than to add a fuller. Either straighten as you go, or pre-bend it a little opposite to the curve you want in your finished blade.

Polishing inside a fuller is enough of an added pain that simply offsetting the curvature induced by forging a single edge wouldn't be worth it.

The "fullers" in some katana were often entirely cut in after forging.
 
I likely don't know what I'm talking about, but is it possible that the fuller can add some lateral strength to a long blade? Like the way a tube is stronger than a solid bar?
 
I believe it is primarily a way to give a blade stiffness and strength by increasing its cross section without adding weight, same concept as an I beam. It would keep the weight down and help balance.

I have a 100 year old bayonet with a deep fuller. It is a strong stout blade designed for rifle mounted bayonet charge. The blade is 1/4" thick at the spine and 17" long, yet it is relatively light and balances just in front of the guard. This is due to the weight reduction of the fuller. You don't want a lot of weight hanging on the end of your rifle.
 
I can't speak from a true swordmaker's perspective but fullering just makes sense when considering structual strength to weight ratios. As far as I know, removing stock will never ADD STRENGTH or RIGIDITY to an object but strategically removing material in order to cut down on weight while preserving as much structual integrity as you can is the logical approach.

There was a recent thread on making fullers.

Rick
 
It doesn't add strength directly, but for a given weight and material it does.

A 1" square solid bar will be somewhat stronger than a 1" heavy wall tube. But it will be 3.4 lbs per foot and a 11 ga tube will only be 1.4 lbs per foot and nearly as stiff and strong (in bending). And a 2" 16 ga will weigh 1.6 pounds per foot and will be stiffer (in bending, until it buckles)

This is sectional modulus or moment of inertia. The gist of it is, the more stuff you have, the greater the distance from the neutral plane, the stiffer the structure. A fuller allows you to move the meat around to achieve a stout blade without the weight.
 
Well, yeah.. But you didn't say anything about a neutral plane. yeh? :p
 
I was always told and I've heard it often repeated that fullers were to relieve the suction when withdrawing a blade from a penetrated body. Is that in fact, just a lot of crap?
 
grumpyphil said:
I was always told and I've heard it often repeated that fullers were to relieve the suction when withdrawing a blade from a penetrated body. Is that in fact, just a lot of crap?
Click to expand...

That's a common error, Grumpy.

To really make swords and bayonets easy to pull from a body, soldiers lubricated their weapon with fullerene. They just rubbed it all over with buckyballs.

Fuller, fullerine, you can see how easy it is to confuse those two. :D
 
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