PocketKNIFE

UTILI-SONG evolved into...

...ROCKHOPPER! ~(Screeaw!)~

Printables link: here.

"But you already designed a balisong," you say. Yes, I did. And it is further said that the definition of insanity is doing the same thing again and expecting a different result.

So I did the same thing again, and I got a different result.

Iteration after iteration, tune after tune, ultimately literally every single component of the original Harrier Utili-Song wound up being changed or in some cases, just outright thrown away and designed anew. This carried on to the extent that I eventually realized we were deep into in a Ship of Theseus situation, and at that point it ought to get a new name. Thus, the Rockhopper was born. So here's another black and white knife coming at you from the deep blue sea.

It is not an optical illusion, but the handles are subtly tapered which was an important aspect I realized was originally missing. There are also ergonomic finger rest cutouts, which also provide a tactile indication of which side of the handle you're holding.

At is core are the headless "Impossible" screws I used on the Adélie design. I liked these so much that I said at the time I would backport the design to my other knives, and here we are.

The next logical step is, of course, to give the Rockhopper bushing pivots to ensure a guaranteed kick-ass action.

And isn't it just. (Slow mo version here. Warning: That file is 28 megabytes. Sorry, instance admins.)

The Rockhopper also has a deep carry pocket clip. I can't think of any production balisong that does. Maybe there's one out there but I'm drawing a blank. Give me an "acktshully" in the comments if I'm wrong.

Oh, yeah.

I also added a Morpho style spring loaded squeeze-to-release latch. The latch head is a new lower profile design, and positively locks in place in both the open and closed configurations unless the handles are squeezed.

I could sit there and do that all day.

The spring latch was what gave me the most trouble. Getting that tuned to work reliably was a major chore, and ultimately revealed that you can't print that component in ordinary PLA if you expect it to work, at least beyond demonstration purposes. Cold creep will eventually do you in if you try, and by "eventually" I actually mean "within a couple of hours of leaving it latched." Which is a real drag.

But if you print the liners in ABS instead there's enough creep resistance in the material to make it possible. ABS will also take a minor set after a while, but its permanent deflection is more limited and at least so far in my testing a pair of ABS liners has kept the spring latch perfectly functional from the start right up until the time of writing.

The entire knife has been slimmed down, especially the blade holder, because it turned out the added thickness was actually unnecessary for function and durability. The thinner design feels much nicer in the hand.

And when I said I did a lot of tuning, believe me when I say I was not fucking around.

Practically every mechanical aspect is parameterized and configurable, which was necessary to dial in everything to be just so.

That's because, and I knew this already, designing a balisong knife is actually unexpectedly difficult and complicated. It doesn't seem like it should be at first blush. I mean, per-industrial Filipino fishermen carved working examples out of whalebone and bamboo or whatever the fuck, right? How hard can it be?

The answer is, very. Making a bali- that spins and goes "clack" is not actually terribly involved. But doing so in a manner that doesn't suck, works reliably every time, and most importantly can be cranked out on a consumer level 3D printer turned out to be quite involved.

Everything is a factor. Everything. The spacing between the cutouts for the Zen pins, and their diameters. Length of the handles. Angle of taper. Length of the latch, to compensate for angle of taper. Clearances between the bushings, the screws, and the blade. Height of the pivot bosses. Interface between the tang and the pins. Everything works in concert with everything else.

If you've ever wondered why Chinese flea market balisongs are such crap, this is exactly why. All of that stuff has to be right, and it has to be consistent, and that's not easy.

I designed the Rockhopper to be an intermediate sized knife. It's 4-15/16" long closed, not including the protrusion to the rear from the clip. Open and latched it's 7-5/8" long, including the length of a typical Stanley style utility knife blade. It's 11.5mm thick or 0.45" in total, again without the clip. And printed with 100% infill in a combination of PLA and ABS, it weighs 36.1 grams or 1.27 ounces.

In length that puts it in between, for sake of example, a Benchmade Model 32 and 51. It's about the same overall length when open as a 32, actually, owing to the longer handles but shorter blade assembly.

I also did a trainer version of the blade, presented here in eye-searing green for safety. This is for practice, or can be used by any prospective waddlers who happen to live someplace with insufficient Freedom^tm^ where live blade balisongs may be illegal.

And I did a better job of it than that damn carrot. At least I can say that for myself.

The Rockhopper is pretty much exactly as complicated on the inside as a Morpho, as well. A full build requires 27 individual components, all of which you get the fun an excitement of assembling to get to the finished product. Once again, I'm not going to detail the assembly process -- which is rather involved -- for the sake of brevity. That's all detailed on my Printables post.

Want one? Of course you do. Get the files here.

On a post a while back I made a comment about nobody making an Axis or crossbar locking knife with a CQC style pocket hook opener on it.

This is what's known as "making a call-back." It establishes a sense of continuity with the reader, which makes them feel good about remembering something you said earlier and gives them a sense of belonging or membership in the community surrounding the brand you're building. See what I did there?

Yes, okay, I'm beating around the bush. You all read the title and saw the headline picture. You know what time it is.

Noot noot, mothercluckers. This is the Adélie, and it's exactly what I said it was. If you've been wondering why my output has been so slow lately and what the hell I've been working on instead, now you know.

And it's fully 3D printable. Well, except the blade, of course. You can grab the Printable here.

The Adélie employs the same design philosophy as my previous two knives, in that it is a printable design that can be produced as-is, requires no supports, and does not rely on any external hardware. Except, again, the blade.

And if you don't mind my saying so, I think it's also pretty rad.

Our reference example is provided in this boss black-and-white penguin color scheme. Boss, that is, except for the fact that photographing a snow white object on my usual white background void while keeping it acceptably visible actually turned out to be literally impossible. Sometimes I'm just really fuckin' smart, aren't I?

So today you get blue. And you also get to see why I never use any of the various colored background swatches my photography box came with, because they're terrible. I'm not even going to try to edit the backgrounds out of these photos. So much for consistency in building that brand.

At its core, the Adélie has a truly functional Axis lock/crossbar lock mechanism. Of course it requires no external springs; the necessary spring action is provided by a pair of flexible prongs built right into the model.

I also incorporated a lot of tricks and mechanical improvements over my previous models, all of which I learned the hard way, and which I will now be obligated to eventually backport to those designs now that I've finished this one. Eventually. Give me a minute, okay?

Let's start with the screws. The biggest weakness of my last two models was easily the printed screws, which had the unfortunate but unavoidable capability of being able to cleave themselves in two via the sheer mechanical advantage afforded by their threads. It turns out that Archimedes guy was on to something after all. The upshot is, and some of you probably found out, if you put any torque whatsoever on the old screw design after they reached the point of bottoming out, the heads would just ream right off.

The solution to this turned out to be to make screws that just... don't have heads. I don't know why I didn't think of it sooner.

"That clearly would not work," you say. Well, yes, that is unless every single part that the screw goes through is meticulously designed with a single uninterrupted helical thread all the way through the entire assembly.

Let's talk other features.

The Adélie has a fully reversible, deep carry pocket clip.

It also has the aforementioned Emerson/CQC style pocket hook on it for snappy automatic deployment when you draw it, by way of snagging just so on the hem of your pants as it clears the fabric.

You know what? It occurs to me that for all the times I've yammered about the damn Emerson Wave^tm^ CQC pocket hook opening action, I've never displayed how it actually works.

That's how it works. Fast, clean, elegant. But this isn't the Wave^tm^, because even though Emerson's patent on that expired in 2017, its shape and name are still trademarked. So this is the Penguin Opener.

If you feel like it, you can also use the penguin's beak to open the knife manually with your thumb. I was actually going to put a thumb stud through him, but I determined throughout my testing of various designs that it actually wasn't necessary.

And of course Benchmade's Axis lock patent expired in 2016, so along with every other knifemaker in the world I stole that, too. Surely, though, a plastic 3D printed knockoff of the same cannot be opened with the "Axis flick."

Wrong.

The Adélie has a bushing pivot system. That's design improvement #3. The net result of that is that you can cleanly flick it both open and closed, although owing to the blade carrier's very light weight it takes a bit more finesse than with a commercial knife that's made of... you know, metal and stuff.

The CQC-6K comparison is a bit more on the nose today than usual. The Adélie is 6-5/16" long when open, including the protrusion of the clip at the rear. The blade carrier protrudes 2-1/2" from the forward end of the handles, but the exposed portion of the edge is 1-1/8" long. Of course, it takes standard Stanley style utility knife blades which are available in a variety of styles and guises...

...Including these zooty ceramic ones, which with one installed renders the Adélie completely nonmetallic. Make of that what you will.

Fully assembled and with a regular metal blade in it, the reference example weighs just 27.9 grams or 0.98 ounces. Ultralight backpackers, eat your hearts out. Of course, as a non-commercial product you print yourself, the weight will be influenced by what infill percentage you make it and what material or material(s) you print it out of. Maybe some of you have rhodium-infused PLA filament or something to make the blade carrier heavy. I dunno.

It's a bit longer than the Gerber EAB pictured at the bottom, by necessity. The EAB is made of metal, and it does not require any length to be spent on having a tail screw since the body is a unitary machined piece of steel.

I'm including a disassembly pic with the complete bill of materials just because I got it for free, so to speak. Usually I have to disassemble the knife in question to get this photo, but in this case the Adélie comes disassembled to begin with, all in bits already right off of your print bed. Assembly is, of course, required. I'm not going to go into that here -- this screed is going to be quite long enough already -- but it is all detailed on my Printables post.

It's not serious engineering, this, but some design work did go into the Adélie.

On my previous knives, my screw design was deliberately designed to be operable with a penny, rather than real tools, just to be cheeky. That's not really an option here. With the same single narrow diameter down their entire length, the screws I designed don't quite have the surface area on the head to accept the curvature of a penny's edge. So I had to cast around for some other suitably ridiculous yet readily available tool to match up with.

Ultimately I settled on this, which is one of those promotional giveaway screwdrivers. This one is from the Sloan Valve Company in Franklin Park, Illinois and I've had it since at least the 1980's.

I have oodles of these damn things, and so does anyone else who's been around for a couple of decades. They are precisely the sort of goofy thing that's not quite a real enough tool to actually be useful for much of anything else. I suppose you could also use a normal purpose-built quality screwdriver to assemble your Adélie if you felt like it, but... come on.

I will also leave you with some of the prototype builds I produced while messing around with various tweaks to the mechanism and overall profile.

Now all the internet lost media historians can remain forever wistful over what could have been, rather than what we ultimately got. (For instance, I'm particularly partial to the one with the angled tail and offset rear screw, but it didn't play nice with the pocket clip design so that profile wound up in the bin pretty early on.)

Conclusion: If you want to get your hands on your own one of these, you can download the model files from here.