DIY Cast AR-15 Receivers Are More Interesting Than Expected

For some reason the US News media decided on the AR-15 as the poster child of guns that should not be allowed to be made for, or sold to, the consumer. The words still out on the regulation, but, in a very American response, a whole market sprang up around people saying, “Well, then we’ll just make our own AR-15.”

Ordinarily, we wouldn’t cover this sort of thing, but the work [AR-15Mold] is doing is just so dang interesting. They sell a product that enables the home user to cast an AR-15 receiver out of high performance resin. In the process they made a really informative three part video on the casting process.

A lot of people are interested in the product, and having fun with it. In this two part video series, [Liberty Marksman] cast their receivers and test them to destruction. In one video they see how many rounds they can fire out of the gun before it breaks. When it breaks, they excitedly tear down the gun to see where it failed.

It’s quite a bit of fun to watch. Videos after the break.

Continue reading “DIY Cast AR-15 Receivers Are More Interesting Than Expected”

“That’s Not a Knife…”

[Robin Baumgarten] likes to play dangerously. His latest creation, Knife To Meet You cuts to the quick of cooperative gaming. 3 humans play together against the machine. The object of the game is to hold your button down as long as possible. The game makes this difficult by sweeping a knife across the play field, right at finger level. (Video below.)

Knife to meet you is controlled by a flesh eating Arduino. In addition to reading the controls and driving a servo to move the knife, the Arduino also displays encouraging messages on a 2×20 character LCD.

The idea is to scare people, not to actually slice them up. To this end, the knife is actually a capacitive sensor. When the game detects the knife has contacted soft human flesh, it stops the knife before blood starts flowing. The game indicates a player has been defeated by making several chopping motions toward the loser. If the losing player still has all their digits, a new round begins.

The project was created as part of a 24 hour game jam. The final product is quite nice, built into a wood case that closes up for travel. It even has a carrying handle, so you can bring it to parties and find fresh victims players.

We’re not sure what it is about knives and Arduinos. It was only a few months ago that we saw an Arduino driving a knife wielding tentacle. Could the world’s friendliest microcontroller board be turning on us?
Continue reading ““That’s Not a Knife…””

Snowball Machine Gun

[Mark Rober] is an uncle to three nieces and nephews, and when there is snow on the ground he faces the relentless onslaught of three elite juvenile snowball aces. Lesser men would face the fact that they are over the hill when it comes to snow-based combat, but not [Mark]. He has brought technology to his aid, and with the help of his brother created a snowball machine gun capable of firing 13 snowballs at the unruly youths in half a second.

Power for his creation comes from a leaf blower, and the gun itself is made from ABS pipe fixed onto the blower outlet. Magazines made from pipe with its top section cut away are loaded via a 45 degree junction fitting, and the rate of fire is set by how fast the operator pushes the line of snowballs with a wooden block. He has made full build instructions available as a PDF, so assuming you are reading this in a part of the world where it snows, what are you waiting for! Those of us who live in paces where it rarely snows and what snow we get is wet and slushy can only look on with envy.

The video below has the full story, complete with gratuitous destruction of fruit, youngsters cowering in their snow forts, and finally [Mark] receiving his snowy comeuppance.

Continue reading “Snowball Machine Gun”

Building a Sheet Metal Pistol

Floating around the Internet are plans for a semi-automatic pistol constructed out of sheet metal. Like so many plans for 3D printed guns, it appears no one has actually built one of these pistols. It exists only as a technological construct, with diagrams you can photocopy, trace onto a few bits of metal, and presumably assemble into a gun. The only proof these parts can be turned into a gun-shaped object are a few random blog posts from two years ago showing a very ugly pistol spray painted matte black.

[Clinton Westwood] decided to take up the challenge of turning these plans into a real, working gun. He’s documented his efforts on YouTube and put a bunch of pictures up of the entire build process. The gun doesn’t work quite yet, but it almost does, and he’s doing this entirely in a garage shop, with tools anyone can pick up from Home Depot.

Most of the construction of this gun is simple enough – it’s just sheet metal, after all. The magazine was constructed by tracing the pattern onto a piece of metal, wrapping it around a mandrel, and welding it together. The side plates of the gun, again, were created with a jigsaw. Rifling the barrel – the thing that makes this gun both accurate and legal – required the construction of a few interesting tools. The rifling tool is just a piece of round bar that fits through the barrel. A small piece of a hacksaw blade was cut to fit inside this round bar, and the barrel was cut very slowly with a shop-built tool.

The finished result is something that looks like it came from the finest post-apocalyptic craftsman. A gun that looks cool is useless if it doesn’t work, and here the DIY pistol falls short. The spent casings don’t eject. It’s still a step up from the first build of this gun that was only rumored to fire blanks.

Recently, the world of gunsmithing has been inundated with 3D printed pistols that don’t work, and 3D printed guns that do work, but are somehow 200 years behind the state of the art. We’re happy to see some people are still building things with their hands, and hope [Clinton] can eventually get this gun to work.

Continue reading “Building a Sheet Metal Pistol”

Gatling Gun Shoots Arrows Out of Coke Bottles

[JoergSprave] has done it again. His latest, most ridiculous weapon? A Gatling gun that fires crossbow bolts, using compressed air inside coke bottles — and an electric screwdriver.

For those of you not aware, [Joerg] is our favorite eccentric German maker, a purveyor of slingshots and all things ridiculous and weaponised. He runs the SlingShot Channel on YouTube, and has graced us with things like a slingshot cannon (firing 220lb balls!), a machete slingshot for the upcoming zombie apocalypse, and more.

Each coke bottle has a quick release pneumatic air valve, with a wooden lever attached to it to make opening the valve easier and quicker. The coke bottles are pressurized separately using an air compressor, but can also be filled using a bicycle pump — he got his hands on a pump capable of putting out 300 PSI! Word of safety though — you really don’t want to use coke bottles as pressure vessels — but [Joerge] is crazy so we’ll let it slide. Continue reading “Gatling Gun Shoots Arrows Out of Coke Bottles”

Misleading Tech: Kickstarter, Bomb Sights, and Medical Rejuvinators

Every generation thinks it has unique problems and, I suppose, sometimes it is true. My great-grandfather didn’t have to pick a cell phone plan. However, a lot of things you think are modern problems go back much further than you might think. Consider Kickstarter. Sure, there have been plenty of successful products on Kickstarter. There have also been some misleading duds. I don’t mean the stupid ones like the guy who wants to make a cake or potato salad. I mean the ones that are almost certainly vaporware like the induced dream headgear or the Bluetooth tag with no batteries.

Overpromising and underdelivering is hardly a new problem. In the 30’s The McGregor Rejuvenator promised to reverse aging with magnetism, radio waves, infrared and ultraviolet light. Presumably, this didn’t work. Sometimes products do work, but they don’t live up to their marketing hype. The Segway comes to mind. Despite the hype that it would revolutionize transportation, the scooter is now a vehicle for tourists and mall cops.

One of my favorite examples of an overhyped product comes from World War II: The Norden Bomb Sight. What makes the Norden especially interesting is that even today it has a reputation for being highly accurate. However, if you look into it, the Norden–although a marvel for its day–didn’t always live up to its press.

Continue reading “Misleading Tech: Kickstarter, Bomb Sights, and Medical Rejuvinators”

Powerful Crossbow is Almost Entirely 3D Printed

As it turns out, it’s not feasible to print an entire crossbow yet. But [Dan]’s crossbow build does a good job of leveraging what a 3D printer is good at. Most of the printed parts reside in the crossbow’s trigger group, and the diagrams in the write-up clearly show how the trigger, sear and safety all interact. Particularly nice is the automatic nature of the safety, which is engaged by drawing back the string. We also like the printed spring that keeps the quarrel in place on the bridle, and the Picatinny rail for mounting a scope. Non-printed parts include the aluminum tubes used in the stocks, and the bow itself, a composite design with fiberglass rods inside PVC pipe. The video below shows the crossbow in action, and it looks pretty powerful.

Actually, we’ll partially retract our earlier dismissal of entirely 3D-printed crossbows, but [Dan]’s version is a lot more practical and useful than this model. And for a more traditional crossbow design, check out this entirely hand-made crossbow.

Continue reading “Powerful Crossbow is Almost Entirely 3D Printed”