Sword Construction - iron tangs.

CutlassCollector · 11th April 2013, 02:09 PM

Apologies if this subject has been covered in previous threads but as a relative newcomer I find some aspects of sword construction confusing and not well covered in the books.
For example why are iron tangs hammer welded to steel blades - does this not create a weak point?

Sometimes a faint line offset on each side or a difference in corrosion or even on shiny blades occasionally a difference in shine can be noted which indicates a scarf/lap joint on the blade a few inches from the hilt. At first I wondered why the original bar was just not made a little longer to avoid a join.

Am I correct in assuming that this is often where the iron starts? Is this primarily a European method?
Any information appreciated. CC.

A Senefelder · 11th April 2013, 02:39 PM

While I am an armourer by trade I have monkeyed with blade making a bit with some friends and spent a fair amount of time around some reputible blade smiths. This is actually technically a pretty complicated subject but i'll try to keep it simple. When a sword is swung and contacts a target stress is placed on the sword via kintetic energy. Much of the energy is transmitted to the target as , of course, was the intention but some of it travels both up and down the length of the blade. The energy/stress that travels up the blade to the tip is fairly easilly disperssed ( as long as the temper of the blade is good ) via the blade being able to flex back and forth until dispelled ( this can be seen quite graphically in slow motion ). The portion of the blade from the point of impact back to the tang is a different story. The hilt, especailly at the quillions is a shock trap, it stops the dissipation of that converted transmitted kinetic energy at that point rather sharply and can cause the tang to snap without special provisions. This can be achieved in one of two ways. 1) the blade is tempered, tempering is controlling heat in a set enviornment to molecularlly combine hardness and toughness in the desired ratios for the purpose of the object created ( a sword and a drill bit are not for the same purposes and require different ratios of hardness and toughness for thier purposes ). The tang can be tempered to a different level to be more tough than hard to sustain the shock of the force being trapped by the hilt. This can be very tricky to do. 2) An iron tang can be forge welded to a steel blade. Iron is very tough and cannot be tempered ( tempering is a function of having the right minimum amount of carbon content which iron does not ) thus the blade can be fully tempered without worrying about the tang being tempered wrong and risking breaking under sever impact. Forge welding can also be very tricky to do. A good forge weld is well neigh indestructible ( it is afterall pattern welded blades were made ).

I hope this makes sense.

Richard Furrer · 11th April 2013, 02:59 PM

I have seen scarf welded tangs on many blades from many cultures...Indian,Persian,Chinese,some Japanese knives and tools,and various european blades.
One can argue it is conservation of some materials or some requirement of function.
To determine if it is a functional mechanical requirement we would have to sample the two bits and see if there is indeed a difference...chemically as well as metallurgically.

To my knowledge none have done this type of study.

As far as needing iron in the tang vs steel...one could always just not harden the steel tang and thus have very similar pearlitic properties in the steel as one would find in ferritic iron.
I think a point could be made that the steel in the tang could make another small knife..so why not make another small knife? A forge weld is not a difficult thing to do...takes only minutes once you have the tools and skills.

Ric

CutlassCollector · 11th April 2013, 08:40 PM

Thanks Alan for taking the time for such a comprehensive answer.
I understand better now. So there are a lot more welded joins but most are invisible and the lower part of the blade and the tang are often iron. I guess that makes it easier to stamp makers and inspection marks on the ricasso as well.
Is there any way to tell iron from steel without a lab?

And thanks Ric for widening it out beyond europe.

It would follow that Japanese swordsmiths are an example of following the other route by mastering more complex tempering of the steel.
Many thanks. CC

11th April 2013, 02:09 PM	#1
CutlassCollector Member Join Date: Jan 2013 Location: Scotland Posts: 330	Sword Construction - iron tangs. Apologies if this subject has been covered in previous threads but as a relative newcomer I find some aspects of sword construction confusing and not well covered in the books. For example why are iron tangs hammer welded to steel blades - does this not create a weak point? Sometimes a faint line offset on each side or a difference in corrosion or even on shiny blades occasionally a difference in shine can be noted which indicates a scarf/lap joint on the blade a few inches from the hilt. At first I wondered why the original bar was just not made a little longer to avoid a join. Am I correct in assuming that this is often where the iron starts? Is this primarily a European method? Any information appreciated. CC.

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11th April 2013, 02:39 PM	#2
A Senefelder Member Join Date: Jul 2009 Posts: 214	While I am an armourer by trade I have monkeyed with blade making a bit with some friends and spent a fair amount of time around some reputible blade smiths. This is actually technically a pretty complicated subject but i'll try to keep it simple. When a sword is swung and contacts a target stress is placed on the sword via kintetic energy. Much of the energy is transmitted to the target as , of course, was the intention but some of it travels both up and down the length of the blade. The energy/stress that travels up the blade to the tip is fairly easilly disperssed ( as long as the temper of the blade is good ) via the blade being able to flex back and forth until dispelled ( this can be seen quite graphically in slow motion ). The portion of the blade from the point of impact back to the tang is a different story. The hilt, especailly at the quillions is a shock trap, it stops the dissipation of that converted transmitted kinetic energy at that point rather sharply and can cause the tang to snap without special provisions. This can be achieved in one of two ways. 1) the blade is tempered, tempering is controlling heat in a set enviornment to molecularlly combine hardness and toughness in the desired ratios for the purpose of the object created ( a sword and a drill bit are not for the same purposes and require different ratios of hardness and toughness for thier purposes ). The tang can be tempered to a different level to be more tough than hard to sustain the shock of the force being trapped by the hilt. This can be very tricky to do. 2) An iron tang can be forge welded to a steel blade. Iron is very tough and cannot be tempered ( tempering is a function of having the right minimum amount of carbon content which iron does not ) thus the blade can be fully tempered without worrying about the tang being tempered wrong and risking breaking under sever impact. Forge welding can also be very tricky to do. A good forge weld is well neigh indestructible ( it is afterall pattern welded blades were made ). I hope this makes sense.

11th April 2013, 02:59 PM	#3
Richard Furrer Member Join Date: Mar 2006 Location: Sturgeon Bay, Wisconsin Posts: 163	I have seen scarf welded tangs on many blades from many cultures...Indian,Persian,Chinese,some Japanese knives and tools,and various european blades. One can argue it is conservation of some materials or some requirement of function. To determine if it is a functional mechanical requirement we would have to sample the two bits and see if there is indeed a difference...chemically as well as metallurgically. To my knowledge none have done this type of study. As far as needing iron in the tang vs steel...one could always just not harden the steel tang and thus have very similar pearlitic properties in the steel as one would find in ferritic iron. I think a point could be made that the steel in the tang could make another small knife..so why not make another small knife? A forge weld is not a difficult thing to do...takes only minutes once you have the tools and skills. Ric

11th April 2013, 08:40 PM	#4
CutlassCollector Member Join Date: Jan 2013 Location: Scotland Posts: 330	Thanks Alan for taking the time for such a comprehensive answer. I understand better now. So there are a lot more welded joins but most are invisible and the lower part of the blade and the tang are often iron. I guess that makes it easier to stamp makers and inspection marks on the ricasso as well. Is there any way to tell iron from steel without a lab? And thanks Ric for widening it out beyond europe. It would follow that Japanese swordsmiths are an example of following the other route by mastering more complex tempering of the steel. Many thanks. CC