Question for the smiths..

S

surfer

Joined
Jan 30, 2003
Messages
491
Hello,
I allways wonder about the tang construction, I personally LOVE hidden tangs or mortised tangs.
Now some people say (especeally the tactical lovers) that only a full tang will hold up hard use, but history shows us, that stick tangs were common in swords, kukhuris, hirschfänger - and hold up well.

But now a question:
Some people will say, that a stick tang can hold up, when there are no sharp corners (stress raisers), but a lot of Mastersmiths I see here, do square cuts on the ricasso to fit and solder tightly the guard - I think, that the mastersmiths will know what works and what will fail and have absolute faith in them, so where is the secret?

Maybe you can tell me?

regards
surfer
 
any sharp corner without a slight radius isnt a good idea on a knife. i cut a slight radius on any corner of a knife i'm making. a needle file can be used in small areas if necessary. if i'm using a surface grinder to cut a shoulder i touch the corner of the wheel with a stone to put an ever so slight radius on it. it doesnt take much of a radius.
 
I think what you are seeing is the parallel and perfect fit between the guard/ricasso but, in actuality, there IS a radius 'in there' where the ricasso flows into the tang area and goes through the guard. ;)
 
As well, what can occur at that sharp corner, is that a stress riser - a location of extreme internal stress due to the martensite formation at a localized area - is created upon hardening/quenching that can create a hidden crack that can precipitate into a larger crack that can fail later down the road.
Two methods to avoid this are to either create a small radius at this juncture, or, don't subject it to hardening/quenching stresses!
I have clayed the tang/guard shoulder area (that was filed to a sharp 90 degree corner) to insulate it from quenching stresses and then did absolutely EVERYTHING!!! possible to make it fail, and could not get it to fracture. I did this to prove the mechanical strength of my take-down assembly and could come up with no "real world" test to make the hidden tang fail. Nothing.
Read the latest article in Blade by Wayne Goddard where he addresses this subject.
 
Thanks a lot,
Dawkind, I really refer to 90º angles, cut into the ricasso, where later the guard will be soldered in place.
I don't ask this because I don't think that a knife built like this will not stand up, just thinking that maybe a lot of knives are actually overbuilt.
Even with a sharp 90º corner, it should be REALLY hard to break a piece of 1cm x 5mm carbon steel :)

p.s.
thanks a lot Mr.Andersen for this explication! I saw swords (european 2-handers and sabres) with a slim sticktang AND sharp 90º corners, that shure stood up harder use
that our knives will ever see :)
 
Hello all, and yes there is a radius where the tang joins the shoulders. I usually leave a large radius before and during heat treat and then refine it after heat treat. It does not have to be much but it is there. No sharp corners at that junction.

Brion
 
+1 on what Karl said. I try to leave a slight radius at the tang/ricasso junstion and even on a blade that is "fully" hardened, I never harden the tang or the bit of the ricasso where it joins the tang. Call me lazy, but hidden tang knives are easier for me because I don't have to worry about the back half of the blade being dead straight and parallel on all four sides and cosmetically perfect....lol;)
 
Most narrow tang blades are fit like this (poor drawing but you get the ideea):
 

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