Carothers/Loriendesign Chopper WiP

Another update from Nate;

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I've had a chance to cut chips on the prototype.

I'm starting with precision ground stock for the prototype so I skipped decking it and started with the holes. The pin holes are spotted, drilled, milled with circular interpolation and finish reamed to size. A little extra work making high precision holes now makes the rest of the process go smoother down the road. There are also holes to allow a cutter to plunge areas being skeletonized. The D shaped lanyard hole is drilled with a special D shaped drill bit ;)


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I cut unnecessary weight out of the tang. I leave it solid near the end. It's a mistake to remove too much weight from the very end.


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I cut the fuller in several steps. This is a pretty big ball cutter to plow with, so even with 9,000 pounds of box way grunt behind the cut I can't just cut it in one pass. So it's roughed with a 3/8" ball in several passes using a surface milling routine, prefinished with a 1/2" ball and finished with a fresh 1/2" ball. I use an endmill with a helical gash through the center to prevent a dead zone flat in the middle of the cut.


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a clean fuller


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Then I go in and chamfer everything and mark it as a prototype with a tiny little ball endmill that I write with.


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There's a knife in there somewhere


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Posting to subscribe. This is totally awesome! I love seeing how you design, for obvious reasons.......

Also, I love seeing how the CAD works out to become a knife. NtM, very cool!
 
I just received another update from the Man with the Plan!

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Side two was cut the same way as side one. While I was doing all this, Jo the Machinist was making fixtures. This one fixtures the blade by the accurate holes (remember those?) to cut the belly.

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Then it goes back in edge-up, held by the spine to mill the bevels. This is just a prototype so I'm simply holding it straight up and will cut it in a series of fine steps. In production I'll make an angled fixture to hold it where the cut can be made directly with the side of an endmill, but I'm not making those fixtures until the optional angle is confirmed through prototyping. Something of note is the problem of chatter when making a cut on a tall thin unsupported workpiece. I addressed this with a special 5 flute cutter with uneven flute spacing that reduces harmonics. It has small radii on the corners to reduce the notching left behind in the work when machining this way.


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This is a slow approach and it leaves a stripe texture that is both weaker and drags more in the cut than a smooth side, so I don't normally cut bevels this way, but for the prototype I'll just grind it smooth later.


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There is definitely a knife in there somewhere now


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Creepy knife-making robots at work, I love it! Revealing the knife within the billet by removing everything that isn't the knife.
 
Choppy choppy!

I have A LOT of work to do this winter. There is a trail assessment coming up that I'll be involved in in some form or another, and a part of that is developing future plans for adding trail corridors. A lot of the flagging is already done, then it's on to getting digital tracks, and then on to the cutting. This knife is the ideal companion for the flagging and GPSing, as it's light in weight, yet has reach and as much mechanical advantage built in as I could devise without it becoming dangerously susceptible to lateral deflection. For out and out trail clearing, The North Sword by Dan Keffeler is tough to beat. A little heavy and conspicuous for some applications, though.


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The last machining op on the prototypes was trimming it out on a fixture Jo made. Those accurate holes paying a dividend here because the finished blade fits the scales perfectly.

The blade is sandwiched between metal in the fixture. You can't see it, but there are a couple pieces of brass shim stock in strategic locations to load specific spots to prevent chatter and give a good finish. I was a happy boy when I figured this out, it works like magic.


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pretty trimmed out blade


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A slightly less pretty blade after rough grinding the tool marks off the bevel and heat treat. I didn't take any pictures of heat treat, there's not much to see. This is too long to fit my oven so I took it over to my buddy Chris who has a longer oven. The prototype is just plain jain Precision Marshall A2 (import) with no fancy HT tweaks so I tempered it back pretty conservatively. These measured at HRC 58-59, I'll run the 3V over 60.


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And the finished prototype


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The goal with this knife was a practical large woods knife and light chopper that hits above its weight. This is me trying it out on a 2X4. I'll send one up to you for some involved testing clearing trails.




[video=youtube;bpZEvM0vq3s]https://www.youtube.com/watch?v=bpZEvM0vq3s[/video]


There are a few of these prototypes made now so they'll be going out into the world for some work. The next step is through testing and evaluation and tweaks before starting 1st production in a few weeks.
 
Hmmm 9.5in blade... with Nathan's fit & finish and kydex... Can't go wrong!

Though I might have missed what steel this will be done with? 3v like most of the other knives?

Thanks for sharing. Later!
 
ok.. reading the post took some time and now there is another posting..

A2 will be the steel! sweet!
 
ok.. reading the post took some time and now there is another posting..

A2 will be the steel! sweet!

As I read the posts, the prototypes are A2. But further examination of the thread seems to indicate the production runs will be 3V. I would imagine we will hear from Nathan with a very complete explanation, as is his practice when they are put for sale.
 
That looked like a hard, dry, seasoned 2 x 4. The knife/blade seemed to handle it very well. Can't wait for more. Mike
 
Jo Carothers, demonstrating the serious cutting ability of this knife. Cutting empty cans is way harder than cutting full ones, and it looks like we have a monster on our hands here.

[video=youtube;xIek71plLys]https://www.youtube.com/watch?v=xIek71plLys[/video]
 
This B.M.F. has arrived.
Stay tuned to this thread if you wanna check out some field testing.







And, I even get to muck around a bit;

 
well, if I do, it'll be in the name of science :)
 
Good thing it's Friday- perfect day for goofin off!

[video=youtube;ILWZMoh43dw]https://www.youtube.com/watch?v=ILWZMoh43dw&feature=youtu.be[/video]


[video=youtube;L1DHr08llT0]https://www.youtube.com/watch?v=L1DHr08llT0&feature=youtu.be[/video]

shaved;

 
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