Recurve bow make from wood and skis

bow-made-from-ski

A little face protection is a great idea when first testing out your homemade bow. [Austin Karls] made this recurve bow during what he calls an engineer’s Spring break.

He settled on the idea after seeing a few other projects like it on Reddit. After first drawing up a plan he headed down to the shop to cut out the wooden riser (the middle part of a bow). Unlike traditional recurve bows this is made up of three parts. Traditionally you would laminate different types of wood to achieve the flexibility and tension levels desired. But [Austin] went with a synthetic material: the tips of two skis. Each were cut to the final length and affixed to the riser with a pair of bolts.

After a few test shots he gained confidence in the design and did away with the face mask. Now if you’re in the market to take your existing bow and add some firepower to it you’ll want to look in on this shotgun enhanced compound bow.

[Thanks Schuyler]

Retrotechtacular: Mechanical targeting computers

retrotechtacular-mechanical-computer

The device that these seamen are standing around is a US Navy targeting computer. It doesn’t use electricity, but relies on mechanical computing to adjust trajectories of the ship’s guns. Setting up to twenty-five different attributes by turning cranks and other input mechanisms lets the computer automatically calculate the gun settings necessary to hit a target. These parameters include speed and heading of both the ship and it’s target, wind speed and bearing, and the location of the target in relation to this ship. It boggles the mind to think of the complexity that went into this computer.

The first of this seven part series can be seen after the break. The collection covers shafts,  gears, cams, and differentials. Sounds like it would be quite boring to sit through, huh? But as we’ve come to expect from this style and vintage of training film it packs a remarkable number of simple demonstrations into the footage.

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Remote control car that packs its own Beretta

remote-control-car-packs-a-beretta

We’ve never really thought to ourselves “This RC car is fun, but it really needs more handguns”. And if we did, it certainly would not be a built to undertake with students. But to each his own. [Jerod Michel] is a mathematician working in China. He recently built the project seen above with a group of students. Look closely and you’ll notice that the remote control car includes a remote control Beretta strapped to the side.

He doesn’t have a blog post about the project, but you can find a couple of images and his build instructions after the break. The firearm has a motor attached to the trigger that allows it to be fired by tapping into one of the extra channels on the RC car’s PCB. But you won’t just be firing blindly. The project also includes a video transmitter which can be viewed from an LCD screen mounted on top of the remote control unit. There’s even a laser sight that will show what you’re aiming at.

We wonder what the recoil of the firearm does to this light-weight vehicle?

Build Instructions (.txt file)

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DEFCAD, the island of misfit objects

AR

Defense Distributed, the guys working on 3D printed guns and lower receivers for an AR-15, have a storied history with makers, corporations, and our elected representatives. When the news broke they were designing a 3D printed weapon, their $25,000 leased 3D printer was taken away from them. When their designs were too controversial for Thingiverse, they were taken down. Defense Distributed keeps on firing back, though, and now they’re hosting their own 3D model repo called DEFCAD.

In another one of Defense Distributed’s well-produced promo videos, they make their case for a repository of 3D models that doesn’t respond to takedown requests. Basically, 3D printing is a disruptive technology and is too important to be beholden to copyright lawyers, talking heads of the media, and, “the collusive members of the maker community”.

DEFCAD isn’t only about guns. They plan on hosting anything those in the upper echelons of power don’t like – or at least those with a copyright, patent, or trademark gripe – and never responding to a takedown request. It’s a great idea, somewhat akin to The Pirate Bay for physical objects, but actually popular.

One piece, 3D printed crossbow

bow

Centuries ago, craftsmen and smiths of all sort spent hundreds of hours crafting a crossbow. From the fine craftsmanship that went into making the bow to the impeccable smithing a windlass requires, a lot of effort went into building a machine of war. Since [Chris] has a 3D printer, he figured he could do just as well as these long-dead craftsmen and fabricate a crossbow in under a day.

What’s really interesting about [Chris]‘ crossbow is that it is only a single piece of plastic. The bow is integrated into the stock, and the trigger works by some creative CAD design that takes advantage of the bendability of plastic. The only thing required to shoot a bolt from this crossbow is a piece of string. That, and a few chopsticks.

He won’t be taking part in any sieges, but [Chris]‘ weapon is more than capable of shooting a bolt across a room or launching a balsa wood airplane. You can see an example of this after the break.

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Shock sword works best on foes who fight with multiple blades

shock-sword

This project most certainly has some of Trailer Park Boys rolled into it. We say that because the living room is the only place this will ever been used and this guy’s reaction to getting shocked is exactly how [Ricky] would respond.

The sword on the left has an electronic stun mechanism built into it. it works by energizing two blades which are separated by nylon bolts and spacers. Look closely at the tip and you’ll see the blue glow which indicates high voltage. To shock your victim you have to touch them with both blades at the same time. This is demonstrated in one of the videos after the break. But the real pain comes when [Jonathan] — the guy who built the stun sword — touches it on either side with this pair of blades. His body completes the connection and his NSFW language tells the tale of how it feels.

This thing seems to pack a bit more of a punch than our own stun-gun enabled quadcopter.

[Read more...]

This Maglite is a BB Gun

Maglite BB Gun

This innocent looking Maglite houses a piston and barrel, making it into a functional pneumatic BB gun. A Maglite was chosen due to its high durability, and easy access to the internals. A schrader valve sticks out of the battery cap, which allows the gun to be charged using a standard fitting. A brass tube is used as the barrel, and a piston controls firing.

Firing the gun is simple. First, the whole thing is charged up to the desired pressure. Then the ammunition is inserted into the barrel. At this point, the rubber piston is held against the end of the barrel by the pressure in the gun. By pushing the pin of the valve in, the piston is able to move back slightly. This acts as the trigger, and causes air to rush into the barrel, firing the BB.

The results are fairly impressive. Using a chronograph, the speed of the BB was measured at 850 feet per second. Using the Gas Gun Design Tool simulator, it was estimated that the gun could fire at over 1000 feet per second, and maybe even break the sound barrier.

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