Making a Gun Without a 3D Printer

Around four years ago the world was up in arms over the first gun to be 3D printed. The hype was largely due to the fact that most people don’t understand how easy it is to build a gun without a 3D printer. To that end, you don’t even need access to metal stock, as [FarmCraft101] shows us with this gun made out of melted aluminum cans.

The build starts off by melting over 200 cans down into metal ingots, and then constructing a mold for the gun’s lower. This is the part that is legally regulated (at least in the US), and all other parts of a gun can be purchased without any special considerations. Once the aluminum is poured into the mold, the rough receiver heads over to the machine shop for finishing.

This build is fascinating, both from a machinist’s and blacksmith’s point-of-view and also as a reality check for how easy it is to build a firearm from scratch provided the correct tools are available. Of course, we don’t need to worry about the world being taken over by hoards of angry machinists wielding unlicensed firearms. There’s a lot of time and effort that goes into these builds and even then they won’t all be of the highest quality. Even the first 3D printed guns only fired a handful of times before becoming unusable, so it seems like any homemade firearm, regardless of manufacturing method, has substantial drawbacks.

Thanks to [Rey] for the tip!

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Sparky, the Electric Boat

They say the two best days of a boat owner’s life are the day that they buy the boat and the day they sell it. If you built your boat from scratch though, you might have a few more good days than that. [Paul] at [ElkinsDIY] is no stranger to building boats, but his other creations are a little too heavy for him to easily lift, so his latest is a fully electric, handmade boat that comes in at under 30 pounds and is sure to provide him with many more great days.

While the weight of the boat itself is an improvement over his older designs, this doesn’t include the weight of the batteries and the motor. To increase buoyancy to float this extra weight he made the boat slightly longer. A tiller provides steering and a trolling motor is used for propulsion. As of this video, the boat has a slight leak, but [Paul] plans to shore this up as he hammers out the kinks.

The boat is very manageable for one person and looks like a blast for cruising around the local lakes. Since it’s built with common tools and materials virtually anyone should be able to build something similar, even if you don’t have this specific type of plastic on hand.  And, while this one might not do well in heavy wind or seas, it’s possible to build a small one-person boat that can cross entire oceans.

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Educational Robot for Under $100

While schools have been using robots to educate students in the art of science and engineering for decades now, not every school or teacher can afford to put one of these robots in the hands of their students. For that reason, it’s important to not only improve the robots themselves, but to help drive the costs down to make them more accessible. The CodiBot does this well, and comes in with a price tag well under $100.

The robot itself comes pre-assembled, and while it might seem like students would miss out on actually building the robot, the goal of the robot is to teach coding skills primarily. Some things do need to be connected though, such as the Arduino and other wires, but from there its easy to program the robot to do any number of tasks such as obstacle avoidance and maze navigation. The robot can be programmed using drag-and-drop block programming (similar to Scratch) but can also be programmed the same way any other Arduino can be.

With such a high feature count and low price tag, this might be the key to getting more students exposed to programming in a more exciting and accessible way than is currently available. Of course, if you have a little bit more cash lying around your school, there are some other options available to you as well.

Cryptocurrency Mining Post-Bitcoin

While the age of using your own computer to mine Bitcoin during spare CPU cycles has long passed, average folks aren’t entirely shut out of the cryptocurrency game yet. Luckily, Bitcoin isn’t the only game in town anymore, and with GPUs coming down in price it’s possible to build a mining rig for other currencies like Etherium.

[Chris]’s build starts with some extruded aluminum and a handful of GPUs. He wanted to build something that didn’t take up too much space in the small apartment. Once the main computer was installed, each GPU was installed upwards in the rack, with each set having its own dedicated fan. After installing a fan controller and some plexiglass the rig was up and running, although [Chris] did have to finagle the software a little bit to get all of the GPUs to work properly.

While this build did use some tools that might only be available at a makerspace, like a mill and a 3D printer, the hardware is still within reason with someone with a little cash burning a hole in their pockets. And, if Etherium keeps going up in value like it has been since the summer, it might pay for itself eventually, providing that your electric utility doesn’t charge too much for power.

And if you missed it, we just ran a feature on Etherium.  Check it out.

The Last Interesting Chrysler Had a Gas Turbine Engine

The piston engine has been the king of the transportation industry for well over a century now. It has been manufactured so much that it has become a sort of general-purpose machine that can be used to do quite a bit more than merely move people and cargo from one point to another. Running generators, hydraulic systems, pumps, and heavy machinery are but a few examples of that.

Scale production of this technology also had the effect of driving prices for these engines down, and now virtually everyone in the developed world has cheap and easy access to them. In the transportation world, at least, it looks like its reign might finally be coming to a slow, drawn-out conclusion as electric cars capture more and more market share.

Electric motors aren’t the first technology to try to topple the piston engine from its apex position on top of our modern transportation industry, though. In the 1960s another technology, the gas turbine engine, tried to replace it — and failed.

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Power Planer Brought Back To Life

Having the right tool for the right job is not always possible, but it’s an ideal that’s nice to try to live up to. The problem is that a lot of the time, the right tool is often very expensive. We have found lots of ways around this, though, from building our own CNC machines to finding new ways to electroplate metal. Sometimes, though, the right tool for the job doesn’t have to be improvised or built from scratch, it just falls in your lap.

Admittedly, [Sam]’s power planer didn’t literally fall into her lap, but she did pull this neglected tool from the garbage. With no idea what was wrong with it, [Sam] let it sit on the shelf for years until she finally needed it. Assuming there was a major problem with the tool, she set about replacing the blades and bearings only to find that the likely culprit behind why the planer was thrown away in the first place was a faulty switch. This was likely a deal and circuit-breaker for someone who would use it all day, but not so for someone who only needs it for occasional use.

While some might not consider this a “hack”, it is at least a reminder that one man’s trash is another man’s treasure, especially if that trash only needs new bearings and a switch. There are two lessons here: first, that tools aren’t usually beyond repair, and that it’s possible to find all kinds of tools in the dumpster from people who don’t heed this advice.

Handheld Gimbal with Off-The-Shelf Parts

For anything involving video capture while moving, most videographers, cinematographers, and camera operators turn to a gimbal. In theory it is a simple machine, needing only three sets of bearings to allow the camera to maintain a constant position despite a shifting, moving platform. In practice it’s much more complicated, and gimbals can easily run into the thousands of dollars. While it’s possible to build one to reduce the extravagant cost, few use 100% off-the-shelf parts like [Matt]’s handheld gimbal.

[Matt]’s build was far more involved than bolting some brackets and bearings together, though. Most gimbals for filming are powered, so motors and electronics are required. Not only that, but the entire rig needs to be as balanced as possible to reduce stress on those motors. [Matt] used fishing weights to get everything calibrated, as well as an interesting PID setup.

Be sure to check out the video below to see the gimbal in action. After a lot of trial-and-error, it’s hard to tell the difference between this and a consumer-grade gimbal, and all without the use of a CNC machine or a 3D printer. Of course, if you have access to those kinds of tools, there’s no limit to the types of gimbals you can build.

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