Product Introduction - Slingshots

VHammer TTF in walnut and black paper micarta

Funny enough, through a confluence of circumstances, we ended up making slingshots without ever properly introducing them. Things all got started when one of our members, a long time entheusiast, decided he wanted to design and 3D print himself a Bill Hays Harpy. A little strength and safety testing later (the slingshot failed at 344 pounds force) and other people started wanting them. This turned into a secret menu on our website devoted just to slingshots. Eventually, when we were ready, we made this public; a whole new category of product. 

Our Nit slingshot in lightning strike walnut. 

What started with a single design quickly blossomed into our biggest product range. Slingshots allow for an incredible diversity of materials and shapes, so this really is a playground for us to play with design. 

Our Weaver slingshot shown here in translucent blue (near) and graphite over copper (far) 

Project - Custom Santoku

Completed santoku with lightning strike walnut handle and copper ferrule. 

Funny enough, if the snowy pictures don't make it obvious, this project was completed in December of 2018. Now summer, sweltering in heat and high humidity, it is refreshing to look at these pictures and write up the project. The purpose of this project was simple: provide a functional, elegant, and unique pair of gifts to two dear friends of the company for Christmas. To this end, a wickedly thin ground Japanese style kitchen knife with a little STO flair seemed like just the ticket. 

The first step was acquiring the stock blade. We went with a traditional japanese forged white steel blade done in the western inspired santoku style. These blades are ground for the hand, we went for right-handed, and are wickedly thin and sharp. How thin exactly? Almost zero ground, this example measuring approximately .08mm thick above the microbevel that forms the apex. The Japanese white steel, so named because of the color paper in which it is wrapped, is a low-alloy carbon steel fantastic for easily forming and holding incredibly sharp edges. 

The base blades, here with one handle removed. As you can see the original poplar handle and plastic ferrule are functional but leave much to be desired when it comes to beauty.

These blades aren't sold naked though, in this form they come with plain poplar handles and plastic ferrules. Perfectly functional, but not very pretty. This is what we're here to change. Step one is getting the existing handle off. This proved harder than you might expect. Ultimately the easiest and safest method proved to be cutting the ferrule, cutting a groove in the back of the handle, and driving a cold steel chisel into said groove from the back. This way the wood is split from the blade without damaging it. Note, the blade was installed via a hot tang sunk into a hole drilled into the handle. This is a very firm method of installation, difficult to reverse by simply pulling the blade out. I should note that, at some point, one of us came to our senses and masked the blade so it wasn't quite so dangerous to handle. 

Drilling the walnut blank

We cut blanks from some scrap walnut laying around, using the existing handles as a rough length guide. From there we had to drill out the tang part of the handle. This was something of a guess because we're going to burn in the tang later, so how large a hole you need to start with will depend on your specific wood's burn-out rate as well as tang width. You see half inch here, and next time around I'd go with considerably smaller as the tang sank in effortlessly. 

Lathe turning the walnut blank to maximum external dimensions. This is for bulk material removal only, as nothing on the handle is actually perfectly round. 

Once drilled, the lathe comes in handy to remove the bulk of material from the handle and ferrule area. It is worth noting that these handles aren't round when they're done, they have something of a D shape, and the ferrules are oval, but a lathe is a quick and efficient power tool to rough the oversize square blank down to the maximum dimensions of the oval and D respectively. 

Forming the ferrule area. 

A nice sharp chisel is the tool of choice to finish bringing the front of the handle to the oval cross section for the copper ferrule. Not pictured, a section of copper pipe was cut off using a pipe cutter, deburred, and crushed in the vice to form the correct oval shape. It was then traced onto the front of the handle. 

Pressing the copper ferrule onto the walnut handle for the santoku blade. 

The ferrule was then pressed on. Remember snug is good. From there the handle was masked and the ferrule ground flush with the front of the handle and buffed. The ferrule was then masked and the handle taken over to the belt sander to sand down to finished D profile and brought up to 1000 grit. 

Heat burning the santoku blade into the handle. 

It is rather difficult to operate a hot knife, blowtorch, and camera at the same time, so you'll have to settle for a picture of the aftermath. Tangs on these knives aren't hardened. The blade was masked with a wet rag and the tang heated with a torch. We had expected with the density of walnut much pressing and maybe multiple attempts would be necessary. Surprisingly, it literally fell and sank in like this, no force necessary. Next time we'll start with a smaller hole. 

Angry angry pixies were applied to the handle, lightning striking it, and leaving the scarring you see here. Not pictured was the time spent giving it one final go-over with sandpaper prior to finishing. For a finish we went with flax seed oil. This is food safe and polymerizes nicely, albeit slowly over the course of a week or two. The blade itself was coated, and it was poured and sloshed around inside the tang area as well assuring it'd be protected from corrosion. The one "down side" if you will is that flax seed oil isn't a neutral finish, it is quite yellow, and this can be seen on the blade (which was also coated) in the completion photoshoots. Now the knife is finished and ready for wrapping and gifting. 

Reflections on completion

Completed santoku with lightning strike walnut handle and copper ferrule. 

Night Vision Spotting - IR Illuminators

The compost pile, a favorite hangout for local rodents. Custom aspheric IR illuminator at only ~60 meters as seen through our digital night vision setup. 

A local predator shows up to hunt one of our spots. We left him to it. 

Rodents..... they're a problem. Poison creates ecological issues, trapping is indiscriminate, however night vision combined with an airgun can take a good bite out of the local population if you're so inclined. 

In this particular case we're using a digital night vision rig that sees into the infrared spectrum (hence the odd colors, leaves reflect IR light so appear white), which blissfully uses the existing scope via an adapter. And, of course, we're using an STO Custom IR illuminator. We'll need to test further, but with just a crescent moon out we could easily spot beyond 500 yards with it. This system on a more powerful rifle would be ideal for larger game at longer range, such as coyotes. 

Excellent brightness is the key to sharp high resolution images, in this case at about 60 meters to the target area, I had enough light and resolution to watch individual insects fly, and see the spider's eyes in the grass. Of course, using a lamp has an added benefit of lighting up the eyes of anything with tapetum lucidum. This includes our rodent prey. 

Turns out we weren't the only ones hunting rodents that night. This local cat showed up to hunt our spot, or perhaps we were hunting his. Not to fear though, we hit up a couple other spots and had a successful night. 

We're now on Instagram

Eye of Sekhmet figured bubinga over copper, Benchmade 42

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PUT A TRIT ON IT!

Convoy S2+, Nichia 319a 4000K guppydrv, orange tritium vial

As part of our ongoing efforts to put tritium vials on literally everything, may we present to you our mod for the metal switch Convoy S2+. 

Why this light? Well it is sort of odd coincidence, but one day we noticed everyone here at STO was carrying a modded S2+ with a metal tail switch. The mods are all different, and vary greatly in terms of their relative sanity, but they all have the common thread of a metal tail switch because we all love how crisp and clean of an interface it allows. This particular S2+ is one of my personal EDCs, hence the weathered look which is hard earned, and is a pretty mild combination of new driver, upgraded thermal management, optical tuning, and a Nicha 319A in 4000K. It combines good visual acuity for tools and small parts up close, but still has enough go-juice to illuminate targets out to about 150 yards. (subjective real-world distance observations, not ANSI based) 

Convoy S2+, Nichia 319a 4000K guppydrv, orange tritium vial

So how to mod these lights for a nice big trit? There were several goals we wanted to achieve regarding placement. First and foremost we wanted the illumination to be visible from both the rear of the light, and from the side with as wide a viewing angle as possible. This makes the light very convenient to spot under the maximum number of circumstances. Most pointedly, when it is sitting lens-down on your nightstand, it shouldn't need a specific orientation to be very visible so it is quick and easy to grab in the dark. (presumably next to the trits in your pistol sights) Second, we wanted the trit to be held as securely, well supported, and as protected as was reasonable. The reasons behind this are obvious, but they run somewhat counter to the first requirement; the more protected the trit is, such as machined into a solid deep slot, the less visible it would be. Third and finally we wanted as much of the trit's light to be used as possible. End-on installation for example is very easy to do, but only a tiny fraction of the trit's total light exits the end. 

Convoy S2+, Nichia 319a 4000K guppydrv, orange tritium vial

What we settled on is a machined side-slot and a saddle cut into the side of the tail switch housing. It seems simple and obvious once you see it, and we feel it accomplishes our goals very well. When the light is head-standing, and your eye is parallel to the top of it, the trit is directly visible from almost 360 degrees rotation, and where it isn't directly visible there tends to be enough spill that the light's location is obvious anyway. The trit is also, of course, very visible when viewed from the rear. It is well protected, being several milimeters below the top of the light, below the metal switch housing too. And, finally, it is securely held at both its ends and center, as it sits in a saddle cut into the switch housing. Retention could be further increased by adding adhesive underneath the full length of the trit where it rests against the inside rear face of the light, however so far this hasn't proven necessary. 

Spyderco Military titanium-g10 black S30v blade, deep blue tritium vial

And that is how we did it. Now we just need to get trits onto every single other piece of EDC equipment. 

Project - Print Durability Demonstration

Our Storm of Ra, a light with an impressive lumen/throw ratio and an entirely 3D printed chassis. 

With the advent of new technologies come obvious questions: how good is something? Will it last? How is this different from a consumer grade item? In the case of our lights with major 3D printed components, we've repeatedly gotten these sorts of questions, no doubt spurred with less-than-positive experiences with prints off of earlier more fragile 3D printed technologies (such as early SLA) or brittle PLA printed parts off consumer grade 3D printers. We can say that these prints are different, they're done on custom built professional grade 3D printers, strong and impact resistant polymers are used, structures are designed for durability, etc, but what about a more tangible demonstration? 

A thin, light weight, and elegant slingshot design called the Harpy from Bill Hays. This interpertation clocks in at just 41 grams. 

A recent personal project from a member of STO was an excellent demonstration of this performance. This individual wanted to make a slingshot, print it out, but before use wanted to test strength. After all, if the fork on a slingshot were to break off the results would be unpleasant at best, dangerous at worse. The design is based off the Bill Hays Harpy, which has very slender and comparatively weak forks. So we clamped it up in a vice, attached some paracord to the forks, put a load cell in the middle, attached the other end to a winch, and pulled until it broke. 

Remember this is the same material we make most of our flashlights out of run on the same machines. The result? Well for starters we had to get a larger load cell, as our standard 50 kilogram one wasn't enough. Failure occurred at 156 kilograms (344 pounds), and amazingly our camera captured the PRECISE moment of failure. Keep in mind this wasn't a solid print, an exercise in maximizing strength, or anything else like that. Just an experiment to see what a fairly normal print profile would endure. Remember this slingshot only weighed 41 grams, meaning it held 3.6 thousand times its own weight. 

Funny enough, we had the opportunity to repeat the experiment on a slightly more robust slingshot fork design. Our load cell is only rated to 300 kilograms. We chickened out at 260 kilograms (570 pounds force), with NO FAILURE TO THE FORK WHATSOEVER. Below is a gallery of the before, after, and a lousy peak force image taken from far far away behind a tool cabinet. 

The pairing of a 3D printed fork/grip/rest assembly with carbon fiber tubes to form an extremely strong but lightweight slingshot. 

So we hope this goes a little distance toward answering the question of how strong our printed parts are. They're certainly not indestructable, nothing is, however they are remarkably robust. 

Our Lance of Ra showing here a semi-translucent 3D printed head. 

Ferro Rods - Product Introduction

Our ferrocerium rods next to one of our scalpeldashi and sheath. 

Every EDC needs a good fire source. Ferrocerium rods are BY FAR the most reliable and longest lasting option. Each rod can be scraped by anything from the back of a knife to the edge of a rock or broken piece of glass to produce sparks in excess of 5000 degrees Fahrenheit, and this can be done thousands of times on each rod. No batteries to go dead, fuel to leak out, flint to get wet, just reliable hot ignition strike after strike. We offer ours with a variety of cool and exotic handle options, perfect to toss in your pocket or loop on your keychain. 

A night exposure showing the shower of sparks off one of our ferrocerium rods. With a little practice, you don't need a proper tinder ball, this can light more substantial materials. No delicate ember-transfer game here. 

Project - Hasselblad XPan Lens Shade

Hasselblad XPan with our reproduction lens shade. Note the original lens cap function remains unaffected. 

For those not already aware, Hasselblad are the makers of some of the finest film cameras ever made. The XPan is a discontinued panoramic 35mm film camera, which is to say it uses the standard, or at least what used to be the standard, 35mm film however takes non-standard exceptionally wide (panoramic) exposures on it. In an era when 35mm film cameras are falling in value like rocks (take the Nikon F5 for example, arguably the finest pro 35mm film camera body ever made, they were over 3000$ in the 1990s and now can be had for an order of magnitude less), unusual gems such as the Hasselblad XPan are skyrocketing in price. 

Hasselblad XPan with our reproduction lens shade.

A friend of the company, and lucky owner of a few Hasselblads, came to us with an issue. The 45 and 90 mm lenses for the XPan each came with an usual lens shade. To my knowledge, the number of lens shades produced matched the number of lenses, they were never sold as after-market. Unfortunately the design was rather delicate and prone to cracking over time. Broken ones now are expensive, pristine ones even more so, and that is if you're lucky enough to even be able to find one. Could we precisely replicate the design? 

The lens shade alone. Here you can see on the bottom left an embossed indexing mark for installation alignment. (same positioning as the original) 

It took a few tries, but as you may have guessed from the images the answer is obviously yes. We did up a couple, both in full opacity black polymer, using ABS for some and Polycarbonate Alloy for others. The shade matches the original design profile and style, and attaches via the original bayonet mount indexing off a small mark. Use of the original cap is even preserved. Why the two materials though? A function of lens shades isn't just to protect the lens from flare, but to protect the objective and the entire camera from bumps, scratches, and god forbid a drop. ABS offers a great finish, good impact resistance, and good durability. Polycarbonate Alloy however has EXCEPTIONAL impact properties and elongation at break. This makes for a lens shade even better able to mop up the odd bump and keep running. In both cases the bayonet mount on the shade is intended to, in the event of a catastrophic drop, act as a mechanical fuse, sacrificing the shade to absorb energy rather than transmit it to the camera mounts potentially breaking them. 

Bayonet mount at the base of the lens shade. 

And there you have it. Lens shade for an exotic antique irreplaceable film camera? DONE!

Scalpeldashi - Product Introduction

Our Scalpeldashi, seen here with copper or bronze composite handles. 

The unholy union between a scalpel and a kiridashi, the Scalpeldashi is a long running concept we've been slowly simmering. All sorts of different production technologies have been experimented with, the end goal being to keep the design beautiful and exotic but the price reasonable. This production run is available in an exotic copper and bronze composite.