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I Forge Iron

A Destruction Test Knife WIP


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Ok, without further a due, I offer up for your scrutiny......

.... a knife I have named:

INTRINSIC MOTIVATION w/ custom MMS

Blade: Aldo's 1084FG, 8 1/2" of sharp edge, 1 7/8" at its widest, 3/16" at the ricasso with forged distal taper and bevels and semi-brute de forge finish. Hand rubbed to 1000 grit finish with a peened copper maker's mark tag. Sharp as hell!

Handle: 5 1/4" American Wild Black Cherry, stainless steel pins and buffed Watco Danish Oil finish. Forged and etched 1/4" mild steel S-guard w/ gun blued faces and high-polished edges

MMS: (Motivational Management System)
This is made using Wickett & Craig veg tanned leather with hand-cut lacing and hand-made copper beads(turned on my drill press). The handle "cuff" is heavily contoured on the inner face then wet-formed to create a true custom fit with taught, smooth edges. All leather parts have a lightly buffed Bear Grease finish.
NOTE:
This, one of a kind and yet to be tested, knife retention device is something I was drawing up in my brain from day-one of the build. Lately I've watched countless videos of chopping contests and I've seen several versions of both fore and aft mounted lanyards. This is my version.... to me it makes sense. I wanted something that was functional, adjustable, removable, and not cumbersome, but I also wanted something that looked purposeful and as if it belonged. I went through three versions of the handle piece and settled on this one, but I also made a more versatile version that could fitted to other knife designs.

The photos:
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Some of you may have detected why I'm using THIS blade and THIS knife for a destruction test.......

I forged and shaped this blade as an intended gift for my neighbor who has become a great friend. He's a hunting guide. It was to be a start-of-hunting-season present. I drew up a design I thought he'd be happy with and actually use. The blade forged out just fine and the shaping and grinding went well. I was starting to like the blade. I began to clean it up a bit an play with the layout. That's when I drilled the holes for the peened copper plate. One hole was off.... wayyyy off, making the copper tag all askew and odd looking, and I couldn't figure out how to fix it.

That's when this became a destructive test knife.

It was to have a much thicker wrought iron guard, much like I made for "Thorn"(posted here several weeks ago), and a Figured Oak handle with copper accents.

If I had to pick one defining feature/sequence of this build, it would be the S-guard. By choosing to use it, I limited the dimensions I could make the handle. As it is, the bottom edge of the handle does not line up with the bottom of the ricasso. Its a fraction to short because that's all the flat space I had to work with on the guard. I probably could have spent more time modifying the guard to that end, but its a somewhat fruitless process. The guard was made several weeks ago as a practice piece for the one on "Thorn". The shape of this guard fit the original design I drew for this knife. So, its not meant for this knife, but I went with it. That decision dictated everything that followed... to a degree.

The blade is hard, straight and sharp. The knife is well balanced, solid in the hand and lighter than I thought it would be. I think its fairly well built. We'll see.

Now I'm off to make another one of these knives and hopefully my neighbor will have it in time. But first, I'm off to find some rope and 2x4's. I'll revisit this thread when I'm ready for the testing.

Thank you all for following along with this thread. I've enjoyed the conversation and I will benefit from the tips and constructive criticism. Please continue to offer up any advice that I can use to make my knives better.

Thank You,

Peter

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  • 2 weeks later...

Well, last night I did the dirty deed.

My friend's woodworking shop provided the venue for the destruction test. Along for the entertainment was Glen(a retired IBM exec), Blain(a guitar and violin maker) and Blain's son( just a neat kid). Glen shot the video while Blain-and-son cowered in the corner ducking the occasional wood chip.

The rope is brand new 1 1/4" manilla.
The 2x4 is, well.... a 2x4, that has been stored under cover outdoors for many moons.
Here is the uncut video. No, my voice does NOT sound like that, but that shouldn't detract from my Emmy-worthy performance. Shades of De Niro I dare say.......



**If one of you tech wizards can do the embedding thing, that'd be wonderful.**

I probably should have shown the blade/knife pre-test in the video. Suffice to say, however, that it was in the same condition as when last posted here.

On the first swipe at the rope, I hit the rope on the ricasso. My wife, of course, pointed out the obvious... that my aim was off.... Thanks sweety! The second, successful, swipe was about an inch below the first attempt. Prior to the filmed attempt, I did a practice cut which easily went clean through. The successful filmed cut actually wasn't as smooth as that first one. I think I just had a bad angle.
In the video, I mention that the blade failed at about 45 degrees. After looking at the video, it looks like the blade failed closer to 35 degrees or so.

The 2x4 chop went fine, although I started to tire towards the end of the second cut and my accuracy went down the toilet.

The hair shave also went fine. Glen didn't get the best shot of this, but it did shave smooth and clean with the portion of the blade used for the chopping.

Overall, I am happy with the performance of the knife. It performed the tasks a knife should be able to perform. The big question I am left with is: Why did it crack on the spine and not on the edge... isn't that the reverse from what is expected?

Here's a few still photos:
This is Glen helping set up the rope in his shop:
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This is Blain's vice that will be used for the bend test:
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The 2x4 set-up:
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First chop:
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Second chop:
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The successful rope cut:
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The post-test edge:
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What does this photo tell you?
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And finally... Intrinsic Motivation.... Destroyed!!
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It looks like it failed in a series of dimples that were left after grinding. This may have caused some stress concentrations on the tensioned surface, which being in the thickest part of the blade ended up under the highest tension so failed first.

Phil

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How did you harden and temper the blade? Im guessing that the whole blade was hardened and then tempered the same across the blade. If this is the case then the spine being thicker than with the edge and both being the same hardness the spine had way less flex that the edge and causing the spine to start cracking first. Have you tried a differentially tempering one of you blades or doing a soft back draw? Of course this is just a guess but its the only one that makes sense to me.

James

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I've greatly enjoyed this thread; thanks for your hard work, both on knife and documentation.

Re the failure: I tend to agree with the stress riser comments but the fractured surface also looks coarse grained to my eye. Perhaps a couple full anneals and lower final drawing temp?

I have hunted a lot of game in my life and this pattern looks very interesting for a hog killing knife. Catch 'em with the cur dogs and go to sticking...it has all the features of being useful in close engagement, especially the handle shape and leather drop strap.

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