Testing the blade-to-handle joint on a hollow handle survival knife.

Mark Knapp

Mark Knapp

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Dec 20, 2009
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Specifically, I tested the attachment of the blade to the handle on my 1911 Combat Survivor. The 1911 Combat Survivor, for those that have not seen it, is a hollow handle survival knife based on a 1911 Colt Auto grip frame. In it you can carry an extra magazine for your pistol or you can carry a survival clip equipped with a diamond sharpening hone, magnesium ferric fire starter, fish hooks, needles, a Leatherman Micra, synthetic sinew and a flash light.

Here it is.
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I recently upgraded my method of making the attachment. Till now I was pinning and soldering it, the thought was that it would be stronger than welding. I was worried that welding the hardened 154CM blade to the softer 304SS could be weak due to cracking. I decided to TIG weld one up and test it.

The first thing I did after welding it was beat it on the anvil to see if it would crack. I beat on it with a hammer and gave it a good work out. It had no effect.

Next I cut a hole in the blade so I could hook to some heavy stuff.

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First I hooked it to the bucket of my Bobcat and lifted that.

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Here's what the lash-up looked like.

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It lifted it with no problems.

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I changed the lash-up a little bit for the next two tests to get more of a straight pull.

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Next I hooked it to the back of my wife's car and lifted that. You can see her back wheel is off the ground.

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Here's another look at the hook-up.

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Next I hooked to the guard rail on the edge of my lot to see if I could stretch the knife apart.

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I pulled till the back wheels on my Bobcat came off the ground.

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With close inspection there is no separation between the blade and the guard. You can see all my hammer blows but no gaps opened up and it did not break.

I am confident that my new method of joining the blade to the grip frame is as strong as it could be. Only an integral would be stronger.

If you would like to see some field tests I did on the knife, you can check them out here;

http://1911combatsurvivor.blogspot.com/

All questions and comments are welcomed. I would love to see testing done on other hollow handle survival knives if you want to post them here.

Thanks for looking, Mark
 
Nice Mark I like it. The only testing I've done on hollow handle knives is to use them, chop wood, baton a bit of wood and use a saw. No issues at all on the ones I have.
 
It would seem as though the U.S. Army Corps of Engineers could build a bridge with a couple of those fine blades. The hollow handle on that model is a fine idea.
 
I think that after the tests you demonstrated the method of TIG welding holds up well.
 
Mark,

Very convincing tests with great photos! Give it some time and surely someone will come along and say that your tests are not a fair comparison to "real life" use in the field...and they would never trust a hollow handle knife for batoning and making feather sticks. :rolleyes: :D :thumbup:
 
Nice weld job Mark!:thumbup: I'm not really surprised at the results of your test. :D
 
Interesting knife, I just looked through some older threads about it. With no data to support me, I was a little leery of the pin and solder joint that you were using. Welding, if it can be done properly to a similar surface area, has always struck me as a better joining method.

It looks like you ground the bead down after the weld? I am by no measure an authority on welding, but perhaps machining the bead down with a ball end mill, to leave a slight fillet, would be slightly stronger. It would reduce any stress risers.

As impressive as your tensile tests are, I would think that it might be a good idea to perform some bending tests (in all four directions) as well as some shock/impact tests.

Regardless, it's a neat design and a neat idea. Thanks for sharing!
 
cricketdave said:
Nice Mark I like it. The only testing I've done on hollow handle knives is to use them, chop wood, baton a bit of wood and use a saw. No issues at all on the ones I have.
Click to expand...

Thanks Dave, I know you got a lot of nice HH knives, and use them quite a bit.
 
TAH said:
Mark,

Very convincing tests with great photos! Give it some time and surely someone will come along and say that your tests are not a fair comparison to "real life" use in the field...and they would never trust a hollow handle knife for batoning and making feather sticks. :rolleyes: :D :thumbup:
Click to expand...

Thanks Buddy, Hollow Handle Knives are not for everyone but all we can do is do the best job we can.
 
Muaddib1116 said:
Interesting knife, I just looked through some older threads about it. With no data to support me, I was a little leery of the pin and solder joint that you were using. Welding, if it can be done properly to a similar surface area, has always struck me as a better joining method.

It looks like you ground the bead down after the weld? I am by no measure an authority on welding, but perhaps machining the bead down with a ball end mill, to leave a slight fillet, would be slightly stronger. It would reduce any stress risers.

As impressive as your tensile tests are, I would think that it might be a good idea to perform some bending tests (in all four directions) as well as some shock/impact tests.

Regardless, it's a neat design and a neat idea. Thanks for sharing!
Click to expand...

I am not sure if the solder and pinned joint could have withstood a test like this. I did test them thoroughly through real life use like, batonning, chopping lumber and splitting deer. They held up well but I always wondered if it was the best I could do. Since these knives have a lifetime warranty at that joint, I wanted to be extremely confident in it. I now am. At one point I knew that the joint was the weakest part of the knife, now I know it is not.

I welded the tang on the inside of the knife through access windows that I then welded covers over. They have full 3/16 fillet welds. I like the clean look of the joint on the outside and didn't want welds there. I know that welds can cause undercuts and can cause brittleness around the weld so I did not want them on the outside.

I did do the bending tests and shock impact tests with a hammer and anvil prior to the other tests. I did not have a photographer handy while I was beating on it with a hammer but if you look at the close-up you can see my hammer blows. I hit it with a three pound hammer in every possible way. To do any further tests with bending would only serve to snap the blade and it would not teach us anything about the joint. The blade is 3/16 inches thick, it would take a big dude to break it while holding it in his hand. Of course anyone can snap the tip off of a knife.

I am as confident as I can be that the knife and the joint will hold up to any ordinary use and quite a bit of extraordinary use.

I'm going to do more testing today, stay tuned.

Thanks for your comments, Mark
 
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This time, I wanted to know what it would take to break the knife, and where it would break.

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First, I pounded the knife into a birch log. The log is twenty feet long and 12 inches in diameter.

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Almost there.

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I'm not playing around here, it took about twenty really good blows to get it in. You can see the end starting to mushroom.

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After the knife was all the way in I picked up the end of the log with it, and shook it around some. The log weighed about 150 pounds.

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Then I stood on it. I'm not as chunky as I used to be but I still weigh about 240 pounds. I bounced on it a little bit.

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Then I drove the Bobcat onto it, my buddy Mike, the guy shooting the pictures, said it broke on the second bounce.

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It's interesting to note that it didn't break at the weld but where the tang leaves the guard. It broke through the edges of the two holes that I used to use to pin the blade in. This blade was made before I changed to the new method of attaching it. My next batch of blades will be made without the holes so it should be even stronger. The other thing I noted was how small the grain structure is in the blade. That's a result of the cryogenics that the blades go through after heat treating.

I'm pretty happy with the results of the test. It reenforces what I pretty much already new about the joint, it can take some real punishment. You just can't drive your Bobcat on it, so don't do that.

Thanks for checking it out.
 
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That is a really cool concept, and surprisingly durable. One question though . . . is the mag release button reversible for lefties?
 
Mark, I've followed this knife from creation (or at least from when you first started posting about it a while back) and I'm more impressed each time I see it.

Kudos to you for seeing this project through in the way that you have. You may never convince some about the validity of the joint, but you've made an impressive effort and I have no doubt that it's an excellent design. :thumbup:
 
Strigamort said:
Mark, I've followed this knife from creation (or at least from when you first started posting about it a while back) and I'm more impressed each time I see it.

Kudos to you for seeing this project through in the way that you have. You may never convince some about the validity of the joint, but you've made an impressive effort and I have no doubt that it's an excellent design. :thumbup:
Click to expand...

Thanks Strig, I appreciate it.
 
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