Full tang or not full tang?

Martyn

Bushcrafter through and through
Aug 7, 2003
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sargey said:
Its common to bend test a blade by placing a scaffold pole or similar over the handle down to the ricasso area

sorry coutel, but common???

i'm all for hard work knife testing, but testing within normal operating parameters. it is a knife after all.

I think Kev means common amongst custom cutlerty makers. While it might not be that common outside of CONUS, it's certainly common amongst ABS members as it's part of the ABS journeyman tests.
 

C_Claycomb

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Oct 6, 2003
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Off the top of my head I can't think of why one would hammer a knife into a tree. However I have heard of two different occassions when people have hammered knives into cliff faces during climbs and used them for hand holds/anchor points.
 

coutel

Member
Sep 25, 2003
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sargey said:
[

sorry coutel, but common???

i'm all for hard work knife testing, but testing within normal operating parameters. it is a knife after all.

.

No need top be sorry!

'Common' refers to knife makers destruct testing their own knives.....to test the integrity of their hardening and tempering...It gives an idea of flexibilty (return to near true) against not flexing and the degree of breaking. Not scientific, but maybe a bit more scientific than hammering a knife into a tree and jumping up and down on it!!!

Its also a 'common' test for American Bladesmith standards.

The plus side is that IF I can make a knife that will pass the integrity tests I ask in my workshop, then it will probably stand up to your abuse of hammering them in trees and using them as steps. :lol:
 
M

Mike Stewart

Guest
Gentlemen,

If I could just make a quick point,

The ABS test on knives is for hand forged blades and is the standard of THEIR organisation. There are other Hand forged Associations that are totally opposed to the views of the ABS. One is the Oshoken Society that maintains that you should not be able to bend the blade no matter what you use to try to bent it with. These are both American associations and are opposed on a lot of things.

I guess my point is that all these tests are highly subjective.

I have noticed that on all forums you have very different folks that also have different critera for testing. Here I see a lot of carving, batoning, making fuzz sticks etc. You will find other places that will be cutting free handing manila rope- cutting half filled beer/soda cans in half with blinding speed,-- hacking manufactured 2x4s in half and shaving of arm-leg-and body hair.

All of these tests are valid for the folks who do them. The mixed results they get just show that certian knives are better for certian tasks than others. If you know what you want your knife to do--you are way ahead of the game.

Just my two cents,

Mike.......
 

coutel

Member
Sep 25, 2003
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Mike Stewart said:
Gentlemen,

If I could just make a quick point,

The ABS test on knives is for hand forged blades and is the standard of THEIR organisation. There are other Hand forged Associations that are totally opposed to the views of the ABS. One is the Oshoken Society that maintains that you should not be able to bend the blade no matter what you use to try to bent it with. These are both American associations and are opposed on a lot of things.

I guess my point is that all these tests are highly subjective.

I agree. In fact, I dont think that the manner that the ABS bend test is conducted is conclusive to proving it is a good blade, and I dont think its meant to be....It is more a test of what the smith can do with a piece of steel after its shown to be able to chop, cut and shave without edge damage.

A blade that can bend and stays bent is IMO too soft, and would be a failure of what I am trying to achieve. I want strength coupled with some flexing/springing before total failure.

Thats why I moved the leverage up the handle, as the handle integrity was not usualy tested (by me anyway!).



I am interested in the Oshoken Society tests/organisation mentioned. I tried an internet search but couldnt find any thing. Do you have any links?

The comment about 'not bending no matter what is used to bend it' is interesting.
Surely if sufficient force is applied, then steel will eventualy either bend, flex of snap (or is there something else?).
If the steel did not show any signs of bending or flexing, then I would expect that eventual failure (snapping?) would be sudden and dramatic.....There has to be a point of failure..unless its kryptonite :)

Anyway...I am digressing.....The comment was originaly about tang designs and strength..and I was only suggesting that the tang (or blade) is only going to be as strong as the weakest link.....and in my 'backroom' testing, I found the weak link was sometimes the ricasso just in front of the handle....so changed my methods to improve this. :eek:\:
 

Martyn

Bushcrafter through and through
Aug 7, 2003
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coutel said:
I found the weak link was often the ricasso just in front of the handle....so changed my methods to improve this. :eek:\:

That's interesting kev, you mentioned this before. I cant remember reading how you resolved it though. What did you change to strengthen the blade at this point. Also, just for clarity, do you mean the point at wghich the tang joins the blade, or where the plunge is? The meat of the (usually thick) ricasso itself surely isn't the weak point?
 
M

Mike Stewart

Guest
I have never seen a well made blade break through the ricasso. I have seen many blades break at the junction of the ricasso and the tang. This would be at the front of the handle of a hidden tang knife. This is usually a design problem. The step down from the full height of the ricasso to the width of the tang that went through the guard and handle was too dramatic or too sharp cornered. Either condition can lead to a broken knife.

On my hidden tang models I usually have a three inch tang in the handle on a sporting knife. Longer and wider on a big blade chopper.

Proper construction and design are the indicators of strength. All knives , if made properly , are plenty strong for any knid of hand held use.

Please remember that a japanese full length Katana only has a four inch tang. I have never heard of one of those breaking.


Mike.........
 

coutel

Member
Sep 25, 2003
18
0
Martyn said:
coutel said:
I found the weak link was often the ricasso just in front of the handle....so changed my methods to improve this. :eek:\:

That's interesting kev, you mentioned this before. I cant remember reading how you resolved it though. What did you change to strengthen the blade at this point. Also, just for clarity, do you mean the point at wghich the tang joins the blade, or where the plunge is? The meat of the (usually thick) ricasso itself surely isn't the weak point?


Ricasso can be a weak point at the handle junction especialy if its a hidden tang where shoulders could be a weakness...either too soft (annealed) or too hard (fracture).

And its only really going to show as a problem under extreme abuse/testing where leverage is applied on the handle....Is it going to be a problem under normal use?.....doubt it.


Simple to correct...awarness, design and heat treatment.

... Placing the leverage point for a bend test at or below the ricasso is cheating :lol:

:eek:T:
 

ESpy

Settler
Aug 28, 2003
925
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Hampshire
www.britishblades.com
Mike Stewart said:
... the Oshoken Society that maintains that you should not be able to bend the blade no matter what you use to try to bent it with.

Give me a lever and a place to stand...
And I'll bend or break any blade with alacrity.
Assuming the vice holds up, that is!
 
M

Mike Stewart

Guest
Peter,

I am wholheartedly against destruction testing ,but I do agree with you that , if you want to break a knife it is more than possible.

I was just relaying the Oshoken Society position. Those guys hand forge their blades. I do not. All of my blades are stock removal.

I think that any normal hand held test of knives is valid. The test should be tailored to the purpose the knife was designed for and you can push that envelope a bit but to hold a knife to a criteria that far exceeds it's design ,is fun to do and can be eye opening for what you actually can accomplish, it can also be misleading. In other words, folks who read a test to destruction might just remember the destruction and not all of the positively accomplished tasks that the knife performed. I have seen this happen a number of times in my 25+ years in this industry.

I'll give you a quick example. If you are testing a folding knife and go through a whole bunch of cutting tests that the knife accomplishes well and then put a breaker bar(pipe) on the handle with the blade in a vise you will break out the pivot pin. If that is photographed and shown, that may imprint the potential customer with only that portion of the test. He or She may think that the knife is inferior in some way and not buy the knife. The validity of the test won't be questioned by a lot of folks because they saw it on a forum or in a book. People have a tendancy of believing what the see and read.

Now, there may be an exception.... If a maker claims that His or Her knife will do something , it is valid to duplicate that test. To be fair, you must duplicate the task exactlly as the maker claims.

At Bark River we like to work with our customers and develop knives that they want and need. We are very open about what we make-why we make it that way- and how they would like to see it improved. We are very comfortable with that position and enjoy the interaction.

All the best,

Mike........
 

coutel

Member
Sep 25, 2003
18
0
Mike Stewart said:
Peter,

I am wholheartedly against destruction testing ,but I do agree with you that , if you want to break a knife it is more than possible.
quote]

As a small time knife maker, who forges my own knives , make my own damascus and does all my own heat treatment...occasional testing to destruction is absolutely necessary....

When the steel snaps it gives the opportunity to look at the grain growth , make assessments and make changes to my thermal cycles and heat treatment if I feel its necessary. ..

It could be argued than an 'owner/non knife maker' is seeing what punishment the knife can take before total failure, but a maker is testing for more 'scientific'? reasons.



Kevin.
 
M

Mike Stewart

Guest
Kevin,

We do test our own blades and I assume other makers do also. It is good to hear that you do too. This is more than normal for a maker.

When reviewers do this without saying -up front- that their intent is to destruct test the knife it is a bit out of line ,in my opinion.

If a knife fails in hand held -common tasks then the reviewer is on his own to say or not say what happened. This is not the same case as purposely breaking something and acting like the item failed to do the task for which it was designed.

In the past I have actually asked reviewers (two) to purposely break one of my knives. Since I told them to do it ,I was more than willing to have them publish the results. They , in fact , did so. Both Gentlemen showed how much abuse it took to break the knife. It was a very positive review. It was also done at my request. Both men were creative in how they did it and the public reaction to the tests were great.

All the best,

Mike.......
 

ESpy

Settler
Aug 28, 2003
925
57
54
Hampshire
www.britishblades.com
Mike Stewart said:
When reviewers do this without saying -up front- that their intent is to destruct test the knife it is a bit out of line ,in my opinion.

If a knife fails in hand held -common tasks then the reviewer is on his own to say or not say what happened. This is not the same case as purposely breaking something and acting like the item failed to do the task for which it was designed.

Point taken.

As a maker - albeit even smaller-time than Kevin :) - I do want to know just how much it takes to utterly destroy a blade. I *like* NDT techniques, but I can't really afford the equipment needed to perform them! I think Kevin has probably destroyed more blades than I've made.

I think I know that sort of tests you are getting at - and I wouldn't, for example, expect a Woodlore knife to cut through breezeblocks or metal firedoors; I would expect it to cut, split and carve wood until the cows come home without suffering. Horses for courses, as ever.
 
N

narsil

Guest
I think that destruction testing is as much about improving ones skills as a knife maker as being a realistic test for suitability for use. It is very easy indeed to make a knife that will never ever bend. Just don't bother to temper it.
It is also important to remember that the ABS test includes a cutting test as well as a bend test. Toughness and hardness are two desirable but mutually contradictory properties in a steel blade. The skill is to find the best compromise for the intended use and extract the maximum possible performance from the material. There are a whole range of techniques which can be used to achieve this aim, many of them requiring conciderable skill on the part of the maker. Bend testing is just one way to evaluate how well you've done.

IMO destruction testing is an essential part of developing the skills of a kife maker, without it you just don't know where the limits are so you cant push them back.

I do agree though that it is not nessicarily a particularly useful indicator of how well a kife will perform in the field.
 

sargey

Mod
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Member of Bushcraft UK Academy
Sep 11, 2003
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been away for a couple of days and i'm still catching up.

coutel, the bar, yes in that context i see what you mean. like many guys, i'm a bit wary of the fashion towards sacrificing performance in favour of robustness, and mis-marketing robustness as performance.

the hammering a knife into a tree thing is an ongoing investigation into a couple of questions.

A: the fact that every survival book has a grain of something stupid. it's a test specified in mors kochanski's bushcraft. i still don't really know if it's stupid or not.

B: if you try it the handle will break before the blade does, can it be done with a stick tang?

if you try it with a thick tactical knife, it's all but impossible to hammer the knife that far into a tree. if you use a really thin slicer, it won't support the weight. so it's really quite a subtley complex test.

the real world application of hammering on the pommel comes from a couple of jobs, a few simple bits of wood work, cutting holes in snare pegs and so on. and a quick and dirty way of splitting wood for firewood.

what i think i can say with a reasonable level of confidence, if it's good, it's good, if it's pants, it's pants. :roll: :-D there are no absolutes. you could say stick tangs are too weak, i can show you Jean-Marc's oak and copper handled puukko. you could say semi tangs are too weak, i could show you some semi tang katanas as mike mentioned. you could say hollow handled survival knives are too weak, i can show you my modified chris reeves sable, and that knife has had more than it's fair share of battering :oops:

cheers, and.
 

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