L'il Jo

Lorien

Lorien

Nose to the Grindstone
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Knifemaker / Craftsman / Service Provider
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Recently I found out that the spouse of a friend of mine wanted to try her hand at competitive cutting. This past world champs saw the sport's first female competitor, and I was stoked on that so I started working on a pattern right away!

There is a good reason why most competition cutting knives look similar to one another. Everything else is based on the curvature at the edge, and with the dimension restrictions in place, there's not a lot to work with... which is what excites me about designing a knife for that use. I like to work within parameters, maybe it's the discipline required to have it conform but still allows a nuanced approach in order for it to look right.

The great thing about custom knives is their customizability. Working with a human who has proportions and preferences- linking them up with an ergonomically correct tool is a fascinating pursuit. That's my day job- setting people up with a bicycle that fits them and meets their needs. It takes a lot of empathy and attention. Humans are pretty fascinating, when it gets down to it.

Anyway, I figured I'd share where I'm at with this so far. I don't know if it will proceed any further than this, but if it does, I'll be sure to report back. In the meantime, I'd love to hear your thoughts regarding the pattern, and/or competitive cutting in general. Or specifically :)


P7054027_zps5lvmwdiq.jpg




 
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Yes, it looks VERY purposeful.

Lorien, as you know, bikes have adjustments with quality hardware. Looking at that handle i conceive of a male/female star pivot to 'tailor' the angle to suit the need or the task. Also An adjustable length handle?

YOU would be savvy enough to get that done. Who knows.

And...sometimes less is more. I'm just thinking out loud.

Good luck. :) I'll stay posted.

Coop
 
SharpByCoop said:
Lorien, as you know, bikes have adjustments with quality hardware. Looking at that handle i conceive of a male/female star pivot to 'tailor' the angle to suit the need or the task. Also An adjustable length handle?
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that's a really interesting suggestion, Coop. In 2011, I had the opportunity to have a conversation with Ron Appleton who creates locking mechanisms for knives which are often based upon bicycle technology. When I read your post, I thought back on that folding machete thing you posting in your Blade show thread.
As for changing handle sizing and whatnot, it's like you're reading my mind! A plan began formulating while I was working on this one which might be a very interesting project down the road ;)

As for the suggestion that this looks like Dan's knife; thank you! That's a huge compliment :)
If you were to put this pattern beside Dan's, you'd see one significant difference and that would be the handle sizing. This one has a pretty tiny handle, while Dan't has to fit into that huge paw of his while still conforming to regs.
 
i love the look of it. i, like coop wondered how wrist angle compared to the edge plane would help or hurt with power/endurance/fatigue. especially since its a female wrist. i wonder if the inventor of the kukri had already studied this.. coop had a great idea !
 
woodster said:
i love the look of it. i, like coop wondered how wrist angle compared to the edge plane would help or hurt with power/endurance/fatigue. especially since its a female wrist. i wonder if the inventor of the kukri had already studied this.. coop had a great idea !
Click to expand...

Nepal's khukuri using folk are/were a fairly egalitarian lot from what I understand. Lots of shared labour. And a small people, besides.

Mechanical advantage is the pursuit every knife maker and designer engages in. An efficient tool for the task is always a foundational goal. That's what makes cutting competition so interesting. There is no one task. There is a pretty full spectrum of tasks which test the skill of the cutter, while demanding a wide range of abilities of the knife. The knife itself is secondary for sure, but it needs to be able to encompass each task while conforming to regulations, so it's a vital role to be sure.
 
Just an idea, on the butt. Not having so much of a pronounced hook. With a fighter I could see more rationale, but this one will have a lanyard. Im wondering if it might pinch the grip?, ..or maybe not.
- Just throwing it out.

Superb job btw, Lorien! Your ability to create and sketch out these designs is amazing.




David
 
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hey David, thanks for the input, and the time, buddy!

the handle is designed for a hand whose fingers take up around 80mm of real estate. In this situation, I have about 5" or 130mm to work with, which is awesome since I can make the handle look less truncated than I would for a big hand. There are actually a couple of positions with this handle for a small hand, and the aggressive hook at the butt is to accommodate the all out, 2x4 chopping requirement. The steep angle present should have the effect of bunching the pinky and ring finger together for a locked 'judo' grip. But we shall see! (hopefully :) )
 
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Dan and I had a chat regarding handle design today, during which he corrected a misconception I had. I hope it will be as instructive to you as it was to me :)
For a competition knife, there is no time to change hand positions. Hmm...I seriously hadn't considered that. I'm never fighting the clock, but for competing, every moment of forward movement is critical- no time for corrections! One sure, confidence inspiring, hand hugging grip is all you need.

Also, perhaps the Osborne Safety Lanyard system places limitations on hand movement as well? Moreso than a rear lanyard, I would think. This is something I've been thinking on all on my own, so I'll call that an hypothesis :)

So, anyway, this thing seems to be taking off. She's registered for her first competition in August, so the pattern will be in the mail tomorrow so the knife can be built in time for some practicing before then. The finished piece might be different than what I drew here, which is cool since I'm working with the honch himself. I hope to learn a lot during this process.
 
Lorien, you're deep man. I feelyuh.
Hey, where are you thinking the sweet spot will be located? Intentional placement of the sweet spot by design could influence blade profile. ____yes ____no ____maybe
I have a Burt Foster chopper/camp blade of similar general design and it did well on everything in my first cutting rodeo/competition except if the cutting challenge called for a pointy tip. I took 2nd place mainly because of the blade (meaning blade and handle) and how naturally and powerfully it could cut yet still be controlable. So I think your design will build in some key advantages. How does location of the sweet spot interact with those other design elements?
 
HTMD said:
Lorien, you're deep man. I feelyuh.
Hey, where are you thinking the sweet spot will be located? Intentional placement of the sweet spot by design could influence blade profile. __X__yes ____no ____maybe
I have a Burt Foster chopper/camp blade of similar general design and it did well on everything in my first cutting rodeo/competition except if the cutting challenge called for a pointy tip. I took 2nd place mainly because of the blade (meaning blade and handle) and how naturally and powerfully it could cut yet still be controlable. So I think your design will build in some key advantages. How does location of the sweet spot interact with those other design elements?
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Astute questions/observations!

I'll be straight up before I go any further; I have not done almost any of the cutting required in competition.

I've done plenty of cutting, but no rawhide, no golf balls, no rope, no straws, no water bottles...none of that stuff. It's all very specialized, and Dan will be the final arbiter of the shape this knife will take, for which I am eternally grateful. I couldn't ask for a better educational experience:)

As for the sweet spot, there are several. Each is designed, (in my mind) to provide a geometry intended to maximize efficiency for particular types of cuts, and particular types of media. Both curvature of the edge profile and tuning of the bevel geometry play the primary rolls in my considerations regarding my approach to design. I'll leave the weighting considerations for another post.

For the wood/rawhide/vertical water bottle, the sweet spot starts about 3" ahead of the grip and ends about 6" from it. This is the area with the most curvature, and is intended to have the most obtuse edge geometry, which in my mind would work best with a smooth shoulder and something approaching a convexed plane, but not quite, since I find good choppers have a little bit of a ridge at the shoulder in order to avoid sticking, while also helping to break chips free. Curvature here gives bite and then shearing in both directions, like an axe. What you lose is speed, considering the knife is moving faster at the tip, you gain in follow-through mass, since the tip end of the blade carries momentum as the chop slows momentum at the point of contact.

This knife has a little more curvature than I think Dan's does, and my thinking here is that this knife is designed for someone who is just over 5' tall and 100#. I want her to have as much mechanical advantage as possible for the component of the contest which eats up the most time and causes the most fatigue. So, not only is the handle designed for her small hand, the geometry of the edge is designed to give her as much advantage as the regs allow, without killing its versatility in approaching the other cuts.

The moving targets, both balls, would be cut anywhere from an inch ahead of the grip to about 4" along, where aim is important. The further out toward the tip, the more difficult it is to take aim and to time the cut for a moving target. The curvature is less dramatic, and the edge more acute as it approaches the handle. As the edge approaches the plunge, it would become the most acute, and the vertical straw cut and vertical paper towel roll cut would be done somewhere in the first inch of edge.

Forward of the chopping sweet spot, the edge profile straightens out, while the bevel geometry becomes more acute. For the hanging rope, you'd use the area just forward of the chopping sweet spot. The curvature of the edge profile, coupled with the slightly fatter bevel will open up the first few strands, and by the time the straighter and keener section of edge moves into the cut, the less curved section will gather and pull the rope into the more acute edge. SNICK!

From the middle to slightly beyond the end of the rope cutting area, you'd slice your paper towel roll into rings, and the fine horizontal cuts, and from the middle of this area all the way to the tip is your water bottle cutting zone. This zone needs to be as long as the bottle is wide, and longer still so that there is room to shear as the blade is pulled through.

Anyway, like I said, this is a new experience for me wrt design, and I'm sure you'll see changes in the finished piece. I'm really looking forward to learning more about it, and to hopefully participate in an event some day.



[video=youtube;qgO5rsI4edQ]https://www.youtube.com/watch?v=qgO5rsI4edQ[/video]
 
For the blade to handle angle: When you place the cutting edge flat on the cutting table the handle should be angled in such a way the wrist in a comfortable position.
That is all the science there is in it.
 
I've seen numerous competitions where 'stabbing' the point of the blade into an object was one of the cutting competition segments. Like holding the knife point down and stabbing ping-pong balls and such.
Was this part of your design plan?
 
Nice job, Dan.
Lorien- This knife would look really good with a Red handle.
 
Karl B. Andersen said:
I've seen numerous competitions where 'stabbing' the point of the blade into an object was one of the cutting competition segments. Like holding the knife point down and stabbing ping-pong balls and such.
Was this part of your design plan?
Click to expand...

Bladesports doesn't have a stabbing component- if so, it'd back to the drawing board!
 
So, Jo has her new competition chopper, courtesy of Dan Keffeler. I put a photo of it in the first post for comparison's sake.

There are numerous differences from the drawing, the most important of which is the kick at the back of the handle, which was a really good idea since that feature adds a lot of safety in that it makes arresting forward momentum much easier and faster.

You'll notice Dan's composite handle approach, which utilizes a combination of terotuf for traction and strength, and neoprene for shock absorbtion.

Sick knife, eh?
 
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