Simple Concepts Behind Complex Coilguns

September 13, 2012 by Mike Szczys 8 Comments

Coil guns use electromagnetic coils to propel a metal projectile. On the surface they may look rather complicated. But when you break down the concepts it’s pretty easy to learn. If you’ve ever thought of dabbling in this field this lengthy coilgun primer will be a great help.

The basic concept of a coilgun comes in three parts: the coil, the voltage source, and the switch that combines the two. In the build above you can see two spools of wire on the clear barrel of the gun. These make up a pair of accelerators which connect to those huge black capacitors supplying the voltage. The switch they used can’t really be seen but from the article we know it’s a Thyristor; a Silicon Controlled Rectifier (2N6504).

In the video after the break you can see these three parts coming together for a test firing. This is the first step in a longer journey. To achieve higher projectile velocities you must add coils, as in the image above. But spacing and timing quickly complicate the simple concept. But if you can work out all the kinks you end up with some pretty great hardware.

Continue reading “Simple Concepts Behind Complex Coilguns” →

Carrot Gun Packs A Punch; Improves Eyesight

September 4, 2012 by Mike Szczys 26 Comments

Just in time for your garden’s carrot harvest [Lou] shows us how to make a carrot firing rifle. It’s cheap, easy, and quick. If you’ve got 15 buck and 15 minutes you can have one to call your own.

The loading method is quite easy. Shove a carrot in the muzzle as far as it will go, then cut of the excess. Finish up by using a ramrod to push the carrot stub the rest of the way into the barrel. Once you’ve gnawed down the rest of the carrot nub and connected a compressor hose to the rifle you’re ready to do some damage. The video after the break shows a carrot fired all the way through a cardboard box, and penetrating a gallon jug of water.

[Lou] uses CPVC for the project. It takes just a few lengths of pipe, pipe fittings, a valve, and a threaded metal compressor fitting. After gluing everything together he threads the compressor attachment in place and heads to the firing range.

Continue reading “Carrot Gun Packs A Punch; Improves Eyesight” →

3D Printed Guns, Laws And Regulations, And Philosophical Discussions On The Nature Of Printed Objects

August 26, 2012 by Brian Benchoff 237 Comments

For as long as they’ve been banded about, 3D printers were regarded as the path to a new economy, a method of distributed manufacturing, and a revolution for the current consumer culture. With every revolution, a few people need to get angry and the guys at Defense Distributed are doing their part to make that happen. They’re designing a handgun able to be printed on a hobbyist-level 3D printer

This isn’t the first time we’ve seen a 3D printable weapon; this 3D printed AR-15 lower receiver is the only part of an AR-15 that contains the ID markings and serial number. Legally, the AR lower is the gun, and requires a background check to purchase (with the footnote that this varies from state to state and country to country – long story short, the BATFE probably isn’t happy about a 3D printed AR lower). The one drawback of a 3D printed AR-15 lower is that every other part of the gun must be purchased elsewhere. This is where Defense Distributed comes in: they propose designing a gun that is 100% printable on a hobbist-level 3D printer such as a RepRap or Makerbot.

Right now, Defense Distributed is looking for funding to produce two gun designs. The first design, WikiWep A will serve as a research build, allowing Defense Distributed to answer a few questions on what can be built with a RepRap. WikiWep B will have moving parts for the firing action and very nearly all the parts will be printable on a RepRap or Makerbot.

In the video Defense Distributed put up for their now cancelled IndieGoGo campaign (available after the break), the guys talk about the distribution of a CAD file of completely 3D printable weapon being a threshold of a new economy where laws and regulations cease to apply. We’re not sure we agree with that statement; after all, anyone with some metal forming tools can build an excellent weapon to acquire another weapon, but we’re interested in seeing what governments and regulators will make of Defense Distributed’s project.

Continue reading “3D Printed Guns, Laws And Regulations, And Philosophical Discussions On The Nature Of Printed Objects” →

Controlling A Spud Gun With An Arduino

August 19, 2012 by Brian Benchoff 18 Comments

We’re a long way from the Aquanet-powered plastic pipe spud guns of our youth. [smirpab] over on the SpudFiles forum posted a work in progress of an amazing replica AS50 sniper rifle he’s building. This pneumatic cannon goes above and beyond any air-powered rifle we’ve seen with an Arduino that is able to switch between automatic, semi-automatic, and burst modes with an LCD display and a rate of fire control.

The mechanics of [smirpab]’s build are fairly normal for this level of pneumatic gun; it shoots 6mm plastic pellets from a smooth bore barrel with using air compressed to about 10 bar (145 psi). The electronics is where this project really shines, with an Arduino controlling the mode of fire (auto, semi-auto, and a 3-round burst), and the number of rounds per second adjustable with a pot.

A very cool project, and looking at the CAD renders of what [smirpab] completed project will look like, we can’t wait to see this build finished. As always, this build comes with the standard Hackaday “you’ll put your eye out, kid” warning. You can check out a video of [smirpab]’s piston after the break, along with a demo of the Arduino-powered control circuit going through all three firing modes.

Continue reading “Controlling A Spud Gun With An Arduino” →

Scale Model Of A Civil War Mortar Shoots Steel Golf Balls

July 31, 2012 by Mike Szczys 27 Comments

[Sir Keyboard Commando] just emerged from his machine shop to show off the 1/6th scale model of a Civil War mortar which he recently finished fabricating. It started with some bar stock that measured four inches in diameter and accepts steel balls the size of golf balls as ammunition.

The bore diameter is 1.725″ which gives just a bit of clearance for the 1.685″ golf ball specs. Each of the steel balls weighs in at just over 11 ounces. You get a really good look at the finished mortar in this test-fire video. It’s quite small but [Sir Keyboard Commando] reports that the full assembled unit still weighs in at a whopping forty pounds.

This certainly isn’t an improvised weapon, but we’re quite surprised to see it being test fired. We’d bet it turns some heads that the local firing range.

[via Reddit]

Ping Pong Ball Barrage

July 30, 2012 by Mike Szczys 21 Comments

What should you do with your down time between sophomore and junior year at MIT? You better build something awesome. [Christian Reed] didn’t disappoint with his newest creation. He calls it the Ping Pong Mauler and we think that’s an appropriate name. It doesn’t just lunch a ball, it belches forth a relentless barrage.

He certainly has no shortage of ammo. A few garbage bags full of the white orbs number at least 3000 strong, and the plastic drum he’s using as a hopper has room for them all. Jamming is an issue and in the image above you can see him working the agitator with his right hand to prevent a clog. The system is mobile, but the shop vacuum used to propel the balls needs AC power. This means there is a tether that keeps it from roaming too far from home. [Christian] included an air tank in the design but apparently the pressurized air doesn’t do much to help with launch speed. That’s good because pressurized ball guns can be scary.

Check out the video after the break to see the ping pongs fly. We bet they’ll be mowing over some strays out in the yard for at least the rest of this summer.

Continue reading “Ping Pong Ball Barrage” →

3D Printed AR-15 Lower Works

July 26, 2012 by Jesse Congdon 82 Comments

Ar15.com user [HaveBlue] has been working for some time on a 3D printed lower receiver, and now reports that the parts are fully working. Using a Stratasys 3D printer from the 90’s [HaveBlue] managed to spin out a modified version of an already available model from cncguns.com. He strengthened the holes for the takedown lugs, which hold the upper and lower halves of the rifle together. Strengthened the bolt hold lugs, which when the magazine is empty lifts a lever assembly that catches the bolt as it springs back to push another round into the chamber. and added an integral trigger guard AKA the bar that surrounds the trigger.

Legally this print is a veritable gauntlet of state and federal regulations. At least in the US. The lower receiver is the part of the rifle that holds the spring and pins that operate the rifle’s trigger safety and hammer assembly, hold the magazine in place, and mount the buttstock/return spring tube. The other key point about the lower receiver is that it contains the primary traceable identification markings, the serial number. All of the parts that are contained within the lower receiver can be ordered online (this varies state to state). In fact, every single other part of the rifle can be bought and sold freely. The only component of the rifle that can not be ordered online, and requires a background check at a gun store, is the body of the lower receiver (we have to keep saying that this varies state to state). Typically laws allow though for the manufacture of this part without a serial number so long as it is never sold to another individual (again, state laws vary widely).

There is some more info on the build at [HaveBlue]’s website here and here, but it is currently down. This sort of steps up 3D printing past the nerf gun stage, but we have seen shot gun and pistol hacks.