Why do you go for a full tang / why do you go for a hidden tang ?

[Hengelo_77]

So when you decide to make a knife a hidden tang or a full tang, what makes you decide what tang kind it will be?

Personaly I prefer the looks of a hidden tang, but some materials look better as a full tang, like snake wood. (imho) Or some materials only (or mostly) come as scales.
I might end up making a frame handle in 2014.

So what makes you decide to go with the tang kind you make?

 

[sunshadow]

If I am making a quick and easy stock removal where strength and durability are not necessary I do a full tang, if I am doing a knife where strength is important, I do a pommeled hidden tang. There is a reason swords are not made with a full tang

-Page

 

[Jason Fry]

If I have enough steel, I usually make full tangs. On the other hand, it seems like you always end up with a 5 or 6 inch piece at the end of the bar. I make hidden tangs out of those shorter pieces.

 

[Rick Marchand]

Page,
Obviously, there is a huge difference between swords and knives. Can you expand your reply to illustrate how a pommeled hidden tang knife has more strength and durability than a full tang? Just for the record, I have moved toward the same conclusion(depending on the construction specs, of course) and just want to hear your take on it... coming from a materials science background.

 

[Karl B. Andersen]

I don't know that one is stronger than the other, but when I crank down on my hidden finials and pull everything forward into one integral unit I know that my hidden tang knife will perform every function required of a cutting instrument.
My JS performance knife was a take-down - hidden tang - and required me to use a three foot cheater bar to get to a 90* flex.
(And that knife was basically a spring tempered spine and returned to within 18 degrees of straight. No bending. Which means it has some pretty darned stiff resistance.)
It survived just fine. :thumbup:

 

[james terrio]

For me it depends almost entirely on questions of aesthetics, and moreso, guard design. (for instance, double guards on full-tang blades are problematic and complicated).

 

[AVigil]

There is a reason swords are not made with a full tang

-Page

I was always told it was dampen vibration from impact to the hand.

 

[sunshadow]

A hidden tang handle system with a properly designed slightly tapered tang surrounded by a block of wood or antler, or other solid material firmly sandwiched between a guard and a pommel becomes a rigid system in which the solid material (handle block) is effectively put under compression by bending forces, and as it should not actually yield it transfers any stress to longitudinal tension on the pommel/tang which is what the steel is best suited for. Any shocks from impacts get dissipated into the handle block, the tang flexes as needed.

With a full tang you have a relatively rigid cross section along the blade axis interrupted by the stress risers introduced by pin or rivet holes, often you have heat issues introduced by soldering or brazing a guard or bolster, or worse, a pinned guard or bolster which puts a stress riser/weak spot right at the point of most leverage in use. A pinned guard or bolster adds an additional element of failure when a nonferrous metal is used as it becomes a non sealed bimetallic junction that when exposed to moisture/salts creates electrolytic erosion with the steel becoming the sacrificial element. When a full tang is put under lateral torsion, the steel tang bends, and the handle scales are put under compressive forces on one side, tensile on the other with the pins/adhesive being exposed to huge stresses. The handle pieces do not work together, but against each other. The scales even before seasonal movement are pulling or pushing against the pins or rivets which are applying splitting forces, and as the whole thing flexes through daily use the fatigue builds around the pin or rivet holes and it becomes a race between the tang, the adhesive, and the handle material as to which will fail first.

-Page

 

[AVigil]

Sounds like a full tang cord wrapped would eliminate all those problems

 

[sunshadow]

Sounds like a full tang cord wrapped would eliminate all those problems

as in no handle except cord, no bolsters or guard, and no holes?, yes, but then you have a short term solution that needs a fair amount of maintenance and adds nothing structurally to the package

(my personal opinion obviously)

-Page

 

[Willie71]

Has this been tested, i.e. forces to failure measured? I'm not disputing or questioning anything here, just curios. We saw a similar debate in cycling. People presented a lot of reasons why carbon fibre would be weaker than aluminum or steel, but when tested, CF had double the strength as aluminum or steel.

 

[sunshadow]

I remember seeing a study of this a coupe of years ago, but I do not remember who did it, and one of the presenters at Ashokan a few years ago talked about handle/tang design and failure mechanisms, which is when I went back to hidden tang designs instead of full tang for my higher end knives. Additionally 25 plus years of experience making custom fencing swords for SCA/Historical Rapier Combat fighters, and fixing/troubleshooting broken weapons from other makers has supported the concept of a hidden tang in tension putting a handle block into compression creating a durable unit capable of withstanding constant torsion and shocks for an extended period of time.

-Page

 

[Willie71]

I remember seeing a study of this a coupe of years ago, but I do not remember who did it, and one of the presenters at Ashokan a few years ago talked about handle/tang design and failure mechanisms, which is when I went back to hidden tang designs instead of full tang for my higher end knives. Additionally 25 plus years of experience making custom fencing swords for SCA/Historical Rapier Combat fighters, and fixing/troubleshooting broken weapons from other makers has supported the concept of a hidden tang in tension putting a handle block into compression creating a durable unit capable of withstanding constant torsion and shocks for an extended period of time.

-Page

Thank you. So what I take from this is there needs to be a pommel and a threaded tang under tension to get the full benefit of the hidden tang design.

 

[Burl Source]

One thing that I did not see anyone mention is movement with the handle material.
Most natural handle materials will move some. Usually caused by climate changes.
If the knife is a stick tang and the handle material is a bit proud of the bolster or guard, slight movement is not so noticeable.

 

[Will52100]

Pretty much what sunshadow said. If I were making an indestructable, or as close as I can get, hard use combat type knife I'd use a hidden tang with mycarta and a steel pommel screwed down tight. Most of my hidden tang knives don't have a pommel and are good for any thing except maybe hamming the pommel.

Here's a pic of an earlier knife that I destroyed. Basically I bent it 90 degrees, then straightened, then bent again until it broke. Then I re clamped it and bent and worked it till it broke again. Then one more time till I ran out of blade. The handle joint showed no deformation what so ever. Every time I've tried that with a full tang the handle failed first. Even with mycarta and Loveless bolts the handle showed damage.

Now were talking about differentially heat treated carbon steel, not stainless. Normally on stainless I do a full tang, on carbon steel I do a hidden tang, generally but not always. My thinking is that with stainless the blade is subject to fail before a well constructed handle of either construction.

One other thing is that a hidden tang has less opportunity for moister to enter the joints over time.

Nothing wrong with either construction method, just be aware of the limitations. I recently bent a hidden tang knife and the stabilized wood failed about the time the blade went to 90 degrees, it didn't come off, just cracked good and proper.

Edited to add, Mark's got a good point about movement in the handle material, it'll really show up on a full tang. One other thing too, if I put a pommel on a natural material that likes to move much, I make it a floating pommel. Meaning that it's not screwed to the tang, but has a tang of it's on, that way the handle can shrink and expand without developing cracks from compression. Learned that the hard way with some elk sheds.